Perovskite solar cells that were designed by researchers from the National University of Singapore (NUS) have achieved a groundbreaking world record.
The perovskite solar cells attained a power conversion efficiency of 24.35%, with an active area of 1cm 2. This achievement paves the way for cheaper, more efficient, and more durable solar cells.
Before the NUS team’s record-breaking feat, the best-performing 1cm 2 cell recorded a power conversion efficiency of 23.7%. This groundbreaking achievement in maximising power generation from next-generation renewable energy sources will be crucial to securing the world’s energy future.
A paper detailing the study, ‘Solar Cell Efficiency Tables,’ was published in Progress in Photovoltaics.
Making breakthrough discoveries in the development of perovskites
Perovskites are a class of materials that exhibit high light absorption efficiency and ease of fabrication, making them promising for solar cell applications.
Perovskite solar cells have achieved several breakthroughs in the past decade, and the technology continues to evolve.
“To address this challenge, we undertook a dedicated effort to develop innovative and scalable technologies to improve our solar cells’ efficiency. Our objective was to bridge the power conversion efficiency gap and unlock the full potential of larger devices,” explained Assistant Professor Hou Yi, the NUS research team leader.
He added: “Building on more than 14 years of perovskite solar cell development, this work represents the first instance of an inverted-structure perovskite solar cell exceeding the normal structured perovskite solar cells with an active area of 1cm 2.
“This is mainly attributed to the innovative transporting material incorporated in our perovskite solar cells. Since these cells offer excellent stability and scalability, achieving a higher efficiency than for normal-structured perovskite cells represents a significant milestone in commercialising this cutting-edge technology.”
What makes these perovskite solar cells different to others?
The record-breaking power conversion efficiency was made by successfully incorporating a novel interface material into the cells.
Dr Li Jia, a postdoctoral researcher at the Solar Energy Research Institute of Singapore, commented: “Our findings set the stage for the accelerated commercialisation and integration of solar cells into various energy systems.
“We are excited by the prospects of our invention, which represents a major contribution to a sustainable and renewable energy future.”
Moving towards a greener future
The research team wants to build on this exciting development and push the potential of solar cell technology even further.
Their future FOCUS is to improve the stability of perovskite solar cells, as these materials are susceptible to moisture and can degrade over time.
“We are developing a customised accelerating ageing methodology to bring this technology from the lab to the fab. One of our next goals is to deliver perovskite solar cells with 25 years of operational stability,” Professor Hou said.
Additionally, the team is working on scaling up the cells to modules by expanding their dimensions. This will demonstrate their viability and effectiveness on a larger scale.
Professor Hou concluded: “The insights gained from our current study will serve as a roadmap for developing stable, and eventually, commercially-viable perovskite solar cell products that demonstrate a great power conversion efficiency.
“They will serve as a sustainable energy solution that can help reduce our reliance on fossil fuels.”
Titanium Dioxide Nanoparticles Biosynthesis for Dye Sensitized Solar Cells application: Review
Agnes Mbonyiryivuze 1. 2 Sidiki Zongo 1. 2. Abdoulaye Diallo 1. 2. Sone Bertrand 1. 2. Evariste Minani 1. 3. Lakhan Lal Yadav 1. 3. Bonex Mwakikunga 1. 4. Simon Mokhotjwa Dhlamini 1. 5. Malik Maaza 1. 2
1 UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, Pretoria-South Africa
2 Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure road, Somerset West, Western Cape Province, South Africa
3 Mathematics and Physics Department, College of Education, University of Rwanda, KG 11 Ave, Kigali, Rwanda
4 CSIR- National Centre for Nano-Structured Materials, Pretoria, South Africa
5 Deptartment of Physics, Florida Research Centre, University of South Africa, Florida-South Africa
The synthesis of metallic nanoparticles is an active area of academic, application research as well and nanotechnology. Different chemical and physical procedures that are currently used for synthesis of metallic nanoparticles present many problems. These problems include generation of hazardous by-products, use of toxic solvents, and high energy consumption. Biological synthesis of nanoparticles by bacterial, fungi, yeast, and plant extract is the best alternative to develop cost effective, less labor, non-toxic using more green approach, environmentally benign nanoparticles synthesis to avoid adverse effects in many nanomaterials applications. Among the various metal oxide nanoparticles, titanium dioxide nanoparticles have wide applications for dye-sensitized solar cells, in air and water purification, due to their potential oxidation strength, high photo stability and non-toxicity. Till now, titanium dioxide (TiO 2 ) is the cornerstone semiconductors for dye-sensitized (DSSC) nanostructured electrodes for dye-sensitized solar cells. This paper reports an overview of synthesis of TiO 2 nanoparticles by biological means for dye-sensitised solar cell application.
Keywords: titanium dioxide, dye-sensitized solar cells, green chemistry, biosynthesis, nanoparticles
Received June 05. 2015; Revised July 18, 2015; Accepted August 24, 2015
Copyright © 2015 Science and Education Publishing. All Rights Reserved.
Cite this article:
- Agnes Mbonyiryivuze, Sidiki Zongo, Abdoulaye Diallo, Sone Bertrand, Evariste Minani, Lakhan Lal Yadav, Bonex Mwakikunga, Simon Mokhotjwa Dhlamini, Malik Maaza. Titanium Dioxide Nanoparticles Biosynthesis for Dye Sensitized Solar Cells application: Review. Physics and Materials Chemistry. Vol. 3, No. 1, 2015, pp 12-17. http://pubs.sciepub.com/pmc/3/1/3
- Mbonyiryivuze, Agnes, et al. Titanium Dioxide Nanoparticles Biosynthesis for Dye Sensitized Solar Cells application: Review. Physics and Materials Chemistry 3.1 (2015): 12-17.
- Mbonyiryivuze, A Zongo, S Diallo, A Bertrand, S Minani, E Yadav, L. L Mwakikunga, B Dhlamini, S. M Maaza, M. (2015). Titanium Dioxide Nanoparticles Biosynthesis for Dye Sensitized Solar Cells application: Review. Physics and Materials Chemistry, 3(1), 12-17.
- Mbonyiryivuze, Agnes, Sidiki Zongo, Abdoulaye Diallo, Sone Bertrand, Evariste Minani, Lakhan Lal Yadav, Bonex Mwakikunga, Simon Mokhotjwa Dhlamini, and Malik Maaza. Titanium Dioxide Nanoparticles Biosynthesis for Dye Sensitized Solar Cells application: Review. Physics and Materials Chemistry 3, no. 1 (2015): 12-17.
Nanoparticles have unique catalytic, optical, magnetic and electrical properties due to their nano-scale dimensions . Metal oxide nanoparticles such as tin oxide, iron oxide, zinc oxide and titanium are very attractive and play a significant role in various device applications [2, 3].
They are also widely used in medicinal fields, electronics, sensors, optics, catalysis, photoelectrochemical devices, drug delivery, biosensors, bio-imaging, antimicrobial activities, food preservation and photonics.
TiO 2 is one of the semiconductors that are mostly used in DSSC.A DSSC is a device for the conversion of visible light power into electricity based on the sensitization of wide Band gap semiconductors such as TiO 2 [2, 4]. Till now, TiO 2 is the cornerstone semiconductor for dye-sensitized nanostructured electrodes for DSSC. Due to the non-toxic, easily available and low cost characteristics, TiO 2 has been the mostly preferred semiconductor for the photoelectrode .
Veiw figure Figures index
DSSC are relatively new class of low-cost solar cells that belong to the group of thin film solar cells. They are very promising compared to silicon based solar cells as they are made from low-cost materials, and do not need sophisticated methods and apparatus to be manufactured [2, 5]. DSSC contains several components: a conducting glass substrate, a mesoporous semiconductor film, a dye sensitizer, an electrolyte or mediator solution with a redox couple as well as counter electrode [2, 5, 6].
Veiw figure Figures index
There are so many different materials used in the literature review for DSSC components. But, since its invention in 1991 over many years ago, the components of the state-of-the art dye-sensitized solar cell did not change a lot relatively . The development has concentrated on the one hand to the change of the properties of the original components, such as the morphology and the surface properties of the TiO 2 electrode [7, 8]. This paper reviewed on the application of TiO 2 for DSSC as well as the biosynthesis of TiO 2 nanoparticles by biological means.
DSSC and TiO 2 Nanoparticles
The historical background of DSSC began in 1839 when the French Physicist Edmond Becquel discovered the photovoltaic effect on which the DSSC operating principle is based [9, 10]. He was doing experiment on illuminated electrode metal in an electrolyte. While he was immersing the two platinum electrodes in an illuminated solution containing a metal halide salt, he realized that there was an electric current between these two electrodes [11, 12, 13]. In 1873, the photovoltaic effect in selenium was observed by Willoughby Smith .
In 1883, the first solar cell made of a selenium/gold junction with an efficiency of about 1 % was reported by Charles Fritts . This American inventor, Charles Fritts described this cell in detail for the first time six years later . The theory behind the photovoltaic phenomenon was first described by Albert Einstein in 1904, who won the Nobel Prize in 1921 [12, 15]. The first “Silicon” solar cell was invented by Russell Ohl in 1940 and reported in 1941 . Fourteen years later, it was discovered that the improvement of the efficiency of solar cells can be achieved by doping silicon with certain impurities up to 6% by Gerald Pearson, Calvin Fuller, and Daryl Chapin of Bell Laboratory. This discovery led to a practical application in space craft as early as in 1958 [14, 11].
Actually, there is an interesting convergence of photography and photoelectrochemistry because both phenomena are based on a photoinduced charge separation in a liquid‐solid interface. Before being aware of such similarities and following the experiment developed by Becquerel, Vogel discovered that silver halide emulsions sensitized by a dye resulted in an extended photosensitivity to longer wavelengths in 1873 . Four years later, J. Moser was the first to report the dye‐sensitized photovoltaic effect [12, 16]. Gerischer and Tsubomura together with their co-workers in 1960, discovered dye sensitization of wide Band gap semiconductors where they used ZnO as the semiconductor and different dyes such as rose bengal as photosensitizer .
From that time, several attempts were made to use dye‐sensitized photoelectrochemical cells to convert sunlight into electricity. However, the efficiency of those devices was very low, well below 1 %, mainly due to the poor light harvesting and instability of the dyes employed. O’Regan and Grätzel described for the first time a three dimensional (bulk) heterojunction applied to the fabrication of DSSC. This new device was based on the use of semiconductor films consisting of nanometer‐sized TiO 2 particles, together with newly developed charge‐transfer dyes. These authors report an astonishing efficiency of more than 7 % . The DSSC and its inventor, Prof. Michael Grätzel, have received prestigious awards, including the Balzan Prize in 2009 and the 2010 Millennium Technology Prize, the largest technology prize in the world .
Several companies have accepted the challenge to bring DSSC technology “from the lab to the fab (Dyesol, G24i, Sony, Sharp, and Toyota, among others) .The facile assembly functional cells sensitized with berry juice can be assembled by children within fifteen minutes, the large choice of colors, the option of transparency and mechanical flexibility, and the parallels to natural photosynthesis all contribute to the widespread fascination for DSSC [5, 13, 19].
In 2013, the drastic improvement in the performance of DSSC has been made by Professor Michael Grätzel and co-workers at the Swiss Federal Institute of Technology (EPFL). They have developed a state solid version of DSSC called perovskite-sensitized solar cells that is fabricated by a sequential deposition leading to the high performance of the DSSC. This deposition raised their efficiency up to a record 15% without sacrificing stability . The authors believe that this will open a new era of DSSC development, featuring stability and efficiencies that equal or even surpass today’s best thin-film photovoltaic devices.
2.2. TiO 2 Nanoparticles for DSSC Application
The standard DSSC technology based on a liquid electrolyte and glass substrate are made of a transparent conducting glass electrode coated with porous nanocrystalline titanium dioxide (nc-TiO 2 ); dye molecules attached to the surface of the nc-TiO 2 ; an electrolyte containing a reduction-oxidation couple such as iodide and triiodide ions (I – /I 3 – )and a counter electrode coated by a catalyst [2, 5, 17].
The semiconductor, typically a metal oxide, is responsible for providing the surface for dye adsorption, for collecting electrons from the excited dye and for conducting them towards the external circuit . The Band gap of the semiconductor should be greater than 3 eV in order to let the light pass through the semiconductor easily . In solution under irradiation, oxide semiconductor materials have good stability. Stable oxide cannot absorb visible light because they have relatively wide Band gaps. To be able to absorb light, wide Band gap oxide semiconductor materials (e.g. TiO 2. ZnO and SnO 2 ) are sensitized with photosensitizers that are able to absorb visible light [2, 5, 21].
A great number of common wide energy Band gap semiconductors have been reviewed but anatase TiO 2 is the most used [5, 22]. In addition to TiO 2. other semiconductors used in porous nanocrystalline electrodes include for example: ZnO, CdSe, CdS, WO 3. Fe 2 O 3. SnO 2. Nb 2 O 5. and Ta 2 O 5 [11, 23, 24, 25, 26].
Till now, TiO 2 is the cornerstone semiconductor for dye-sensitized nanostructured electrodes for DSSC. Due to the non-toxic, easily available and low cost characteristics, TiO 2 has been the mostly preferred semiconductor for the photoelectrode [25, 26].
Green Chemistry Approach
The synthesis of metal and metal oxide nanoparticles using green biological methods are favor for the synthesis comparing to physical and chemical methods that are very expensive, environment polluting, consuming more energy, sophisticated process, and time consuming process. Green methods are cost-effective, environmental friendly and easy process .
College essay examples from students accepted to Harvard, Stanford, and other elite schools
Responding effectively to college essay prompts is quite different from other essay writing. The combined challenge of addressing a question in an interesting way while staying focused and making yourself stand out, all within a limited number of words, is something that students struggle with every year. With a wide variety of prompts used by each school, alongside the Common App essays, it can be overwhelming to write strong, memorable essays.
However, there are some standard practices that will help elevate your essay:
- Directly address any questions the prompt asks. Many essay prompts will ask you to write about extracurricular experiences in your life or to list interests such as your favorite movies or music. Be sure to include the answer to any questions and don’t get distracted while providing context or other extra information.
- Use specific information. Make sure to mention the specific volunteer program you worked at or the name of your favorite instructor from your summer STEM camp. While it’s important not to overburden your essay with small details, peppering in a few specifics will highlight what’s important to you both academically and personally.
- Create a narrative. Just like with any story or news article, you want to start your essays with a good hook. Setting the stage for your experiences, including anecdotes to drive home a point, or carrying a thematic element throughout your essay will help keep the reader interested and will show off your creativity.
- Reuse material. There’s no reason to write completely new essays for every school you’re applying to. Many schools ask the same questions with slightly different wording, like the commonly used “diversity essay” which essentially asks how you contribute and benefit from diversity. With some editing, a single essay could answer multiple prompts — and cut down on your stress!
- Put yourself in your reader’s shoes. College admissions officers read hundreds of essays from hopeful applicants with each one thinking their personal experiences and reasons for applying to a particular school are unique. This contributes to the difficulty in standing out in your essays since almost anything you write about will likely have been encountered by your reader before. Putting yourself in your reader’s shoes can help strengthen your writing. Remember, it’s not necessarily about what you say, but how you say it. If you read your essay back to yourself and some of the descriptions sound trite or typical, these are spots that are ripe for improvement. For example, if you describe a trip abroad to help build homes in a developing country with words like “life-changing” and “eye-opening,” you may run the risk of boring your reader. That experience could have been truly life-changing for you, but the simple act of thinking of more creative ways to express an idea not only makes your writing more interesting to read, it signals to your reader the amount of effort you’ve put into your essay. Describing an experience as transformative can sound less cliché and exaggerated. over, allowing your experiences to speak for themselves (showing instead of telling) will display your imagination and grant you space to emphasize what you learned–something always popular with adcoms.
- Go through multiple drafts–and do so early. We can’t stress enough the importance of revision. While your initial ideas may be good, the first couple of drafts will never express them as well as they would after a few edits. Writing takes place in the mind. It’s a thought process that involves reflecting on your experiences and then translating that reflection into words and—most importantly—time. Make sure you start writing your essays as early as possible to grant yourself as much space as possible to revise.
- Be vulnerable / show emotion. Remember that college adcoms are people, not robots reading an essay to make sure you’ve ticked all the boxes for a particular university. Showing some vulnerability or emotion in your writing can make your story come alive for the reader. Keep in mind there is a fine line between “showing emotion” and a sob story. It’s okay to display your vulnerability in an essay, but making the reader feel sorry for you won’t win you any points. Furthermore, showing emotion encompasses feelings of triumph to feelings of struggle. Letting these shine through in your essay demonstrates your passion, which engages your reader.
Here are some example essays from some of the thousands of students we’ve helped get accepted to their dream school.
Note: Some personally identifying details have been changed.
College essay example #1
This is a college essay that worked for Harvard University.
This past summer, I had the privilege of participating in the University of Notre Dame’s Research Experience for Undergraduates (REU) program. Under the mentorship of Professor Wendy Bozeman and Professor Georgia Lebedev from the department of Biological Sciences, my goal this summer was to research the effects of cobalt iron oxide cored (CoFe2O3) titanium dioxide (TiO2) nanoparticles as a scaffold for drug delivery, specifically in the delivery of a compound known as curcumin, a flavonoid known for its anti-inflammatory effects. As a high school student trying to find a research opportunity, it was very difficult to find a place that was willing to take me in, but after many months of trying, I sought the help of my high school biology teacher, who used his resources to help me obtain a position in the program.
Using equipment that a high school student could only dream of using, I was able to map apoptosis (programmed cell death) versus necrosis (cell death due to damage) in HeLa cells, a cervical cancer line, after treating them with curcumin-bound nanoparticles. Using flow cytometry to excite each individually suspended cell with a laser, the scattered light from the cells helped to determine which cells were living, had died from apoptosis or had died from necrosis. Using this collected data, it was possible to determine if the curcumin and/or the nanoparticles had played any significant role on the cervical cancer cells. Later, I was able to image cells in 4D through con-focal microscopy. From growing HeLa cells to trying to kill them with different compounds, I was able to gain the hands-on experience necessary for me to realize once again why I love science.
Living on the Notre Dame campus with other REU students, UND athletes, and other summer school students was a whole other experience that prepared me for the world beyond high school. For 9 weeks, I worked, played and bonded with the other students, and had the opportunity to live the life of an independent college student.
Along with the individually tailored research projects and the housing opportunity, there were seminars on public speaking, trips to the Fermi National Accelerator Laboratory, and one-on-one writing seminars for the end of the summer research papers we were each required to write. By the end of the summer, I wasn’t ready to leave the research that I was doing. While my research didn’t yield definitive results for the effects of curcumin on cervical cancer cells, my research on curcumin-functionalized CoFe2O4/TiO2 core-shell nanoconjugates indicated that there were many unknown factors affecting the HeLa cells, and spurred the lab to expand their research into determining whether or not the timing of the drug delivery mattered and whether or not the position of the binding site of the drugs would alter the results. Through this summer experience, I realized my ambition to pursue a career in research. I always knew that I would want to pursue a future in science, but the exciting world of research where the discoveries are limitless has captured my heart. This school year, the REU program has offered me a year-long job, and despite my obligations as a high school senior preparing for college, I couldn’t give up this offer, and so during this school year, I will be able to further both my research and interest in nanotechnology.
College essay example #2
This student was admitted to Harvard University.
I believe that humans will always have the ability to rise above any situation, because life is what you make of it. We don’t know what life is or why we are in this world; all we know, all we feel, is that we must protect it anyway we can. Buddha said it clearly: “Life is suffering.” Life is meant to be challenging, and really living requires consistent work and review. By default, life is difficult because we must strive to earn happiness and success.
Yet I’ve realized that life is fickler than I had imagined; it can disappear or change at any time. Several of my family members left this world in one last beating symphony; heart attacks seem to be a trend in my family. They left like birds; laughing one minute and in a better place the next.
Steve Jobs inspired me, when in his commencement address to Stanford University in 2005, he said Your time is limited, so don’t waste it living someone else’s life. Don’t be trapped by dogmawhich is living with the results of other people’s thinking. I want to make mistakes, because that is how I learn; I want to follow the beat of my own drum even if it is out of tune. The important thing is to live without regrets, so when my heart ceases to beat, it will make one last happy note and move on.
I want to live my life daily. Every day I want to live. Every morning when I wake up, I want to be excited by the gift of a new day. I know I am being idealistic and young, and that my philosophy on life is comparable to a calculus limit; I will never reach it. But I won’t give up on it because, I can still get infinitely close and that is amazing.
Every day is an apology to my humanity; because I am not perfect, I get to try again and again to get it right. I breathe the peace of eternity, knowing that this stage is temporary; real existence is continuous. The hourglass of life incessantly trickles on and we are powerless to stop it.
So, I will forgive and forget, love and inspire, experience and satire, laugh and cry, accomplish and fail, live and die. This is how I want to live my life, with this optimistic attitude that every day is a second chance. All the time, we have the opportunity to renew our perspective on life, to correct our mistakes, and to simply move on. Like the phoenix I will continue to rise from the ashes, experienced and renewed. I will not waste time for my life is already in flux.
In all its splendorThe Phoenix risesIn a burst of orange and yellowIt soars in the baby blue skyHeading to that Great LightBaptized in the dance of timeFearless, eternal, beautifulIt releases a breathtaking auroraAnd I gasp at the enormity
College essay example #3
This is a college essay that worked for Duke University.
As soon as the patient room door opened, the worst stench I have ever encountered hit me square in the face. Though I had never smelled it before, I knew instinctively what it was: rotting flesh. A small, elderly woman sat in a wheelchair, dressed in a hospital gown and draped in blankets from the neck down with only her gauze-wrapped right leg peering out from under the green material. Dr. Q began unwrapping the leg, and there was no way to be prepared for what I saw next: gangrene-rotted tissue and blackened, dead toes.
Never before had I seen anything this gruesome–as even open surgery paled in comparison. These past two years of shadowing doctors in the operating room have been important for me in solidifying my commitment to pursue medicine, but this situation proved that time in the operating room alone did not quite provide a complete, accurate perspective of a surgeon’s occupation. Doctors in the operating room are calm, cool, and collected, making textbook incisions with machine-like, detached precision. It is a profession founded solely on skill and technique–or so I thought. This grisly experience exposed an entirely different side of this profession I hope to pursue.
Feeling the tug of nausea in my stomach, I forced my gaze from the terrifying wound onto the hopeful face of the ailing woman, seeking to objectively analyze the situation as Dr. Q was struggling to do himself. Slowly and with obvious difficulty, Dr. Q explained that an infection this severe calls for an AKA: Above the Knee Amputation. In the slow, grave silence that ensued, I reflected on how this desperate patient’s very life rests in the hands of a man who has dedicated his entire life to making such difficult decisions as these. I marveled at the compassion in Dr. Q’s promise that this aggressive approach would save the woman’s life. The patient wiped her watery eyes and smiled a long, sad smile. “I trust you, Doc. I trust you.” She shook Dr. Q’s hand, and the doctor and I left the room.
Back in his office, Dr. Q addressed my obvious state of contemplation: “This is the hardest part about what we do as surgeons,” he said, sincerely. “We hurt to heal, and often times people cannot understand that. However, knowing that I’m saving lives every time I operate makes the stress completely worth it.”
Suddenly, everything fell into place for me. This completely different perspective broadened my understanding of the surgical field and changed my initial perception of who and what a surgeon was. I not only want to help those who are ill and injured, but also to be entrusted with difficult decisions the occupation entails. Discovering that surgery is also a moral vocation beyond the generic application of a trained skill set encouraged me. I now understand surgeons to be much more complex practitioners of medicine, and I am certain that this is the field for me.
College essay example #4
In most conventional classrooms, we are taught to memorize material. We study information to regurgitate it on a test and forget it the following day. I thought this was learning. But this past summer, I realized I was wrong.
I attended the SPK Program, a five-week enrichment program with New Jersey’s best and brightest students. I lived on a college campus with 200 students and studied a topic. I selected Physical Science. On the first day of class, our teacher set a box on the table and poured water into the top, and nothing came out. Then, he poured more water in, and everything slowly came out. We were told to figure out what had happened with no phones or textbooks, just our brains. We worked together to discover in the box was a siphon, similar to what is used to pump gas. We spent the next weeks building solar ovens, studying the dynamic of paper planes, diving into the content of the speed of light and space vacuums, among other things. We did this with no textbooks, flashcards, or information to memorize.
During those five weeks, we were not taught impressive terminology or how to ace the AP Physics exam. We were taught how to think. importantly, we were taught how to think together. Learning is not memorization or a competition. Learning is working together to solve the problems around us and better our community. To me, learning is the means to a better future, and that’s exciting.
College essay example #5
This is a college essay that worked for University of Pennsylvania (UPenn).
When I was thirteen and visiting Liberia, I contracted what turned out to be yellow fever. I met with the local doctor, but he couldn’t make a diagnosis simply because he didn’t have access to blood tests and because symptoms such as “My skin feels like it’s on fire” matched many tropical diseases. Luckily, my family managed to drive me several hours away to an urban hospital, where I was treated. Yellow fever shouldn’t be fatal, but in Africa it often is. I couldn’t believe that such a solvable issue could be so severe at the time—so I began to explore.
The exploration led me to the African Disease Prevention Project (ADPP), a non-profit organization associated with several universities. I decided to create the first high school branch of the organization; I liked its unique way of approaching health and social issues. Rather than just raising money and channeling it through third parties, each branch “adopts” one village and travels there to provide for its basic needs. As branch president, I organize events from small stands at public gatherings to 60-person dinner fundraisers in order to raise both money and awareness. I’ve learned how to encourage my peers to meet deadlines, to work around 30 different schedules at once, and to give presentations convincing people why my organization is worth their donation. But overall, ADPP has taught me that small changes can have immense impacts. My branch has helped raise almost 3,000 to build water sanitation plants, construct medical clinics, and develop health education programs in the small village of Zwedru. And the effect doesn’t stop there—by improving one area, our efforts permeate into neighboring villages as they mimic the lifestyle changes that they observe nearby—simple things, like making soap available—can have a big effect. The difference between ADPP and most other organizations is its emphasis on the basics and making changes that last. Working towards those changes to solve real life problems is what excites me.
I found that the same idea of change through simple solutions also rang true during my recent summer internship at Dr. Martin Warner’s lab at UCLA. Dr. Martin’s vision involves using already available digital technologies to improve the individualization of healthcare. By using a person’s genome to tailor a treatment for them or using someone’s personal smartphone as a mobile-monitor to remotely diagnose symptoms, everyday technology is harnessed to make significant strides forward. At the lab, I focused on parsing through medical databases and writing programs that analyze cancerous genomes to find relationships between certain cancers and drugs. My analysis resulted in a database of information that physicians can use to prescribe treatments for their patients’ unique cancerous mutations. Now, a pancreatic cancer patient does not need to be the “guinea-pig” for a prototype drug to have a shot at survival: a doctor can choose the best treatment by examining the patient individually instead of relying on population-wide trends. For the first time in my science career, my passion was going to have an immediate effect on other people, and to me, that was enthralling. Dr. Martin’s lab and his book, Digital Healthcare: A New Age of Medicine, have shown me that changing something as simple as how we treat a disease can have a huge impact. I have found that the search for the holy grail of a “cure for cancer” is problematic as nobody knows exactly what it is or where to look—but we can still move forward without it.
Working with Project ADPP and participating in medical research have taught me to approach problems in a new way. Whether it’s a complex genetic disease or a tropical fever, I’ve found that taking small steps often is the best approach. Finding those steps and achieving them is what gets me excited and hungry to explore new solutions in the future.
College essay example #6
This student was admitted to UC Berkeley.
The phenomenon of interdependency, man depending on man for survival, has shaped centuries of human civilization. However, I feel, the youth of today are slowly disconnecting from their community. For the past few years, human connection has intrigued me and witnessing the apathy of my peers has prompted me to engage in various leadership positions in order to motivate them to complete community service and become active members of society.
Less than a year before ninth grade began, my cousin and close friend passed away from cancer, and in the hodge-podge of feelings, I did not emotionally deal with either death. However, a simple tale helped me deal with these deaths and take action.
I was never fully aware of how closely humans rely upon each other until I read The Fall of Freddy the Leaf by Leo Buscaglia in freshman year. The allegory is about a leaf that changes with the seasons, finally dying in the winter, realizing that his purpose was to help the tree thrive. After reading it, I was enlightened on the cycle of life and realized the tremendous impact my actions had on others.
Last year, I joined the American Cancer Society‘s Relay for Life, a twenty-four-hour relay walk-a-thon designed to raise funds for cancer research and create awareness about its early detection. I started a team at school, gathered thirty students and chaperones, and raised 800 for the cause. I watched as each student created friendships with other students on our team and members of the Phoenix community. This year, I led a team in the relay for life again with the schoolwide team of 95 members, and we raised 2,900 for the cure for cancer. At first the group leader ship consisted of only my advisor in me; however, I gained the support of the administrators. I spent well over an hour a day preparing for the event, and it was all worth it!
The Sonora Eagles were students of different grade levels, ethnicities, socioeconomic backgrounds, and educational ability. We joked and played football while volunteering. The most important moment occurred during the night’s luminaria ceremony, during which cancer patients of the past and present were commemorated. Our whole team gathered around, and I asked people to share how they have been affected by cancer. As I went through the crowd, their faces illuminated by candlelight, their cheeks were wet with cleansing tears, I realize the impact I had on them, the purpose I was fulfilling; but most importantly, I realized the impact they had had on me. The Sonora Eagles were my means for dealing with the death of my loved ones to cancer.
The theme for relay for life is a hope for a cure. Through this experience as a leader, I have come to realize, as a community, we hope together, we dream together, we work together, and we succeed together. This is the phenomenon of interdependency, the interconnectedness of life, the pivotal reason for human existence. I have continued this momentum by starting a Sonora High School chapter of American Cancer Society Youth, a club dedicated to youth involvement and several aspects of the American Cancer Society, including the recent Arizona Proposition 45.
Each one of us leaves behind a legacy as we fulfill our purpose in life. I believe my purpose as a student is to encourage others to become active community members and motivate them to reach new heights. As a student of the University of California, I will contribute my understanding of the human condition and student motivation to help strengthen student relationships within the campus and throughout the community.
College essay example #7
This is a college essay that worked for Cornell University.
My fingers know instinctively, without a thought. They turn the dial, just as they have hundreds of times before, until a soft, metallic click echoes into my eardrum and triggers their unconscious stop. I exultantly thrust open my locker door, exposing its deepest bowels candidly to the wide halls of the high school. The bright lights shine back, brashly revealing every crevice, nook, and cranny, gleaming across its scintillating, bare surfaces. On this first day of senior year, I set out upon my task. I procure an ordinary plastic grocery bag from my backpack. The contents inside collectively represent everything about me in high school – they tell a story, one all about me.
I reach in and let my fingers trail around the surfaces of each object. I select my first prey arbitrarily, and as I raise my hand up to eye level, I closely examine this chosen one. A miniature Flamenco dancer stares back at me from the confines of the 3-D rectangular magnet, half popping out as if willing herself to come to life. Instantly, my mind transports me back a few summers before, when I tapped my own heels to traditional music in Spain. I am reminded of my thirst to travel, to explore new cultures utterly different from my familiar home in Modesto, California. I have experienced study abroad in Spain, visited my father’s hometown in China five times, and traveled to many other places such as Paris. As a result, I have developed a restlessness inside me, a need to move on from four years in the same high school, to take advantage of diverse opportunities whenever possible, and to meet interesting people.
I take out the next magnet from my plastic bag. This one shows a panoramic view of the city of Santa Barbara, California. Here, I recall spending six weeks in my glory, not only studying and learning, but actually pursuing new knowledge to add to the repertoire of mankind. I could have easily chosen to spend my summer lazing about; in fact, my parents tried to persuade me into taking a break. Instead, I chose to do advanced molecular biology research at Stanford University. I wanted to immerse myself in my passion for biology and dip into the infinitely rich possibilities of my mind. This challenge was so rewarding to me, while at the same time I had the most fun of my life, because I was able to live with people who shared the same kind of drive and passion as I did.
After sticking up my magnets on the locker door, I ran my fingers across the bottom of the bag, and I realized that one remained. It was a bold, black square, with white block letters proclaiming my motto, “Live the Life You Imagine.” In my four years at Cornell University, I will certainly continue to live life as I imagine, adding my own flavor to the Cornell community, while taking away invaluable experiences of my own.
College essay example #8
This student was admitted to Northwestern University.
As I sip a mug of hot chocolate on a dreary winter’s day, I am already planning in my mind what I will do the next summer. I briefly ponder the traditional routes, such as taking a job or spending most of the summer at the beach. However, I know that I want to do something unique. I am determined to even surpass my last summer, in which I spent one month with a host family in Egypt and twelve days at a leadership conference in New York City. The college courses I have taken at Oregon State University since the summer after 7th grade will no longer provide the kind of challenge I seek.
Six months later, I step off the airplane to find myself surrounded by palm trees, with a view of the open-air airport. I chuckle to myself about the added bonus of good weather, but I know I have come to Palo Alto, California, with a much higher purpose in mind. I will spend six weeks here in my glory, not only studying and learning, but actually pursuing new knowledge to add to the repertoire of mankind. Through the Stanford Institutes of Medicine Summer Research Program, I will earn college credit by conducting original molecular biology research, writing my own research paper, and presenting my findings in a research symposium.
I decided to spend my summer doing research because I knew that I liked scientific thought, and that I would passionately throw myself into any new challenge. I always want to know more – to probe deeper into the laws of the universe, to explore the power and beauty of nature, to solve the most complicated problems. I have an insatiable curiosity and a desire to delve deeper down in the recesses of my intellect. At the Summer Research Program, I found out how much I enjoy thinking critically, solving problems, and applying my knowledge to the real world.
While pursuing research in California, I was also able to meet many similarly motivated, interesting people from across the United States and abroad. As I learned about their unique lifestyles, I also shared with them the diverse perspectives I have gained from my travel abroad and my Chinese cultural heritage. I will never forget the invaluable opportunity I had to explore California along with these bright people.
I could have easily chosen to spend that summer the traditional way; in fact, my parents even tried to persuade me into taking a break. Instead, I chose to do molecular biology research at Stanford University. I wanted to immerse myself in my passion for biology and dip into the infinitely rich possibilities of my mind. This challenge was so rewarding to me, while at the same time I had the most fun of my life, because I was able to live with people who share the same kind of drive and passion as I do.
College essay example #9
This student was admitted to Harvard University.
When I turned twelve, my stepdad turned violent. He became a different person overnight, frequently getting into fights with my mom. I didn’t deal with it well, often crying to my mom’s disappointment, afraid that my life would undo itself in a matter of seconds. You might say that my upbringing was characterized by my parents morphing everyday objects into weapons and me trying to morph into the perfect white walls that stood unmoving while my family fell apart.
This period in my life is not a sob story, but rather, the origin story of my love of writing. During a fight once, my stepdad left the house to retrieve a baseball bat from his truck. He didn’t use it, but I’ll never forget the fear that he would, how close he’d gotten. And in that moment, I did not cry as I was prone to do, but I pulled out a book, and experienced a profound disappearance, one that would always make me associate reading with escapism and healing.
Soon I came to write, filling up loose ruled paper with words, writing in the dark when we didn’t have money to pay for electricity. And as I got older, I began to think that there must be others who were going through this, too. I tried to find them. I created an anonymous blog that centered what it meant for a teenager to find joy even as her life was in shambles. In this blog I kept readers updated with what I was learning, nightly yoga to release tension from the day and affirmations in the morning to counter the shame that was mounting as a result of witnessing weekly my inability to make things better at home.
At that time, I felt uncertain about who I was because I was different online than I was at home or even at school where I was editor of my high school literary journal. It took me a while to understand that I was not the girl who hid in the corner making herself small; I was the one who sought to connect with others who were dealing with the same challenges at home, thinking that maybe in our isolation we could come together. I was able to make enough from my blog to pay some bills in the house and give my mom the courage to kick my stepfather out. When he exited our home, I felt a wind go through it, the house exhaling a giant sigh of relief.
I know this is not the typical background of most students. Sharing my story with like-minded teens helped me understand what I have to offer: my perspective, my unrelenting optimism. Because even as I’ve seen the dark side of what people are capable of, I have also been a star witness to joy and love. I do not experience despair for long because I know that this is just one chapter in a long novel, one that will change the hearts of those who come across it. And I can’t wait to see how it will end.
College essay example #10
This student was accepted at Yale University.
I was a straight A student until I got to high school, where my calm evenings cooking dinner for my siblings turned into hours watching videos, followed by the frantic attempt to finish homework around 4 am. When I got an F on a chemistry pop quiz my mom sat me down to ask me what was happening. I told her I couldn’t FOCUS or keep track of all my materials for classes. I thought she would call me lazy, accuse me of wasting the gift of being an American that she and my father gave me. Instead, she looked around at the walls covered in sticky notes, the index cards scattered on the computer desk, the couch, the table, and she said, “How are your friends managing it?”
It turned out while my peers were struggling to juggle the demands of high school it didn’t seem like they were working as hard to complete simple tasks. They only had to put things in a planner, not make sure the deadlines were placed in multiple locations, physical and digital. At my next doctor’s appointment my mom mentioned that I had a learning problem, but the doctor shook his head and said that I didn’t seem to have ADHD. I was just procrastinating, it’s natural.
My mom took off from her grocery store job to take me to two more appointments to ask about ADHD, the term the doctor had used, but other doctors were not willing to listen. I had As in every class except for World Literature. But I knew something was wrong. After our third doctor visit, I worked with the librarian after school to sift through research on ADHD and other learning disabilities until we came across the term executive functioning. Armed with knowledge, we went to a new doctor, and before my mom could insist that we get testing or get referred to a specialist, the doctor handed us a signed referral. She asked me about the folder in my hand. I told her it was full of my research. My mom mentioned that some doctors had refused to refer us to a specialist because my grades were too high. “It’s because we’re Asian,” she added.
I was shocked at this revelation. The last three doctors had mumbled something about grades but had never said a thing about race. Before I could deny it fervently, the doctor, who was from Taiwan, nodded sympathetically. She said it’s common to miss learning disabilities among different races due to biases. And some adolescents learn to mask symptoms by building systems. “You don’t have to prove anything to me. I believe you should get tested.” My mom thanked her fervently and the doctor said to her, “She’s going to be a great lawyer.”
The semester following the confirmation of my learning disability diagnosis was challenging to say the least. My school switched me out of all of my IB courses to “accommodate my special needs,” and I went back to the library, working with the librarian with numerous index cards and stacks of books to make a case for discrimination. The librarian, who had become my close confidante, introduced me to an academic tutor who specialized in learning disabilities and taught me skills like using redundancy and time management to make it easier for me to grapple with moving parts. He noted that with ADHD, the problem wasn’t always the inability to FOCUS but rather the difficulty focusing without adequate perceived reward. It wasn’t that I was not capable but that I had to make myself sufficiently interested or reiterate why something mattered. This reframe changed my life, and when I came back to the library with my new schedule in hand, the most advanced courses my school had to offer, the librarian said, “You’re going to make a great lawyer.”
I smiled and said, “I’ve heard that before.”
College essay example #11
This student was accepted at the University of Pennsylvania.
My brother and I are exactly one year and one day apart. We look like twins — people confuse us — but we couldn’t be any more different. As children we wore the same clothes, received the same haircut. By the time we got to middle school it was clear that my older brother preferred quiet, indoor activities, while I was a born performer who preferred the theatrical, even when off stage. I took his relative silence to be disinterest and found it offensive. To the chagrin of my parents, we simply didn’t get along.
I didn’t mind having a tense relationship with my brother because I was involved at school. In particular I delved into the world of musical theater in addition to regularly singing solos at our high school choir concerts. I spent hours after school preparing for shows. And when I came home, I practiced as well, falling into a rigorous routine I thought I needed to remain at my best and be competitive for parts.
My bedroom was far enough from my parents so as not to disturb them, but space to practice became an issue with my brother because, well, we shared a room. Imagine him meditating on a window seat while I am belting, trying to sustain a high note. Needless to say, this created tension between us. From my point of view he could have meditated in the living room or while I was at practice, but he wasn’t willing to budge. From his point of view, high school was hard enough without the constant sound of Glee arrangements.
At the start of the semester, I practiced “Circle of Life” for a concert audition. While I could sing it fine in its original key, I had a hard time singing it along with the music because the arrangement of the song we were working on had a key change that was out of my range. I couldn’t change key without my voice cracking as I switched to a head voice. This was the first time I struggled to learn a song, and I was a week from the audition. I was irritable in that period and stopped practicing, declaring I had reached the height of my singing career. My brother experiencing quiet when I got home for the first time in years.
After a couple days of this, when I got home, he asked me to join him in meditation. And feeling my anger at my inability to navigate this song gracefully, I did. It was difficult at first. I was trying to clear my head. Later my brother told me that wasn’t the point. When your mind drifts away, you simply come back, no judgment. I liked the sound of that, and it became my new philosophy. I kept trying at the song, no longer getting angry at myself, and just in time for the audition I was able to maintain power in my voice despite the key change. It was important for me to learn you don’t have to always get everything right the first time and that good things come with continual effort. As for my brother, we no longer argue. I now understand why he prefers the quiet.
College essay example #12
This student was admitted to Brown University.
My parents are aerospace engineers, humble even as their work helps our society explore new frontiers. They believe that you make a stand through the work that you do, not what you say. This is what they taught me. This is what I believed until my sophomore year when I was confronted with a moment where I could not stay quiet.
I live outside of a major city in a small, rural town that’s majority white but for a small South Asian population. My high school wasn’t diverse by any standards. Some students were openly the children of skinheads. After a racist exchange with a student who insulted her and refused to sit at the same lunch table, my best friend, who was Muslim, did not stand for the pledge of allegiance in homeroom the next day.
I hadn’t heard about the encounter that sparked this move on her part and was surprised when she didn’t stand up beside me, hand against her heart, mouth chanting an oath. She hadn’t mentioned any mounting discomfort to me, nor had I noticed anything. Unlike my “patriotic” peers, I was less upset by her refusal to stand up for the pledge of allegiance and more upset that she didn’t share with me that she was hurting and what she was going to do to protest how she was treated because of her beliefs and the color of her skin.
She was suspended for insubordination and when I called her, she said that surely in this situation I might find a way to think of more than my own feelings. I felt ashamed. It didn’t even occur to me to seek to understand what was behind her decision in the first place. I apologized, asking how to best support her. She said it was just important that I listen and understand that she could not thrive in an environment that promoted sameness. She spoke to me with a vulnerability I had never heard before. At the end of our conversation, I apologized profusely. She said she did not need my words and what she needed from me was to take a stand.
This was the opposite of the belief my parents drilled in me. I felt conflicted at first, as if by speaking about the situation I was doing something wrong. However, my friend had to deal with a reality that I did not. And perhaps taking a stand would allow my institution and everyone in it to learn to be a more inclusive space for everyone. Maybe there was a way to take a stand and to do the necessary work to change things.
I started a petition with my friend’s permission to end her suspension and to take disciplinary action instead on the student who had taken racist actions in the first place. Of the 1000 students at my high school, over 200 signed, a number that far exceeded my expectation. When I shared the results with my friend, she said to me, “Because of who you are, you will always have supporters. Use your power to do good.”
Since then, I have tried to be more aware that not everyone experiences comfort in the same environments that I do. Rather than assume everyone feels safe and supported, it’s best to create space to listen and to ask how you can be supportive. My friend and I created a club to foster cross-cultural dialogue. In the past year two other clubs of its kind began at other local schools. than anything I am proud that I have learned to be a better friend and a more thoughtful community member in a way that honors who I am and what I value.
College essay example #13
This is a college essay that worked for Washington University in St. Louis (WashU).
I held my breath as my steady hands gently nestled the crumbly roots of the lettuce plant into the soil trench that I shoveled moments before. Rainwater and sweat dripped from my brow as I meticulously patted and pressed the surrounding earth, stamping the leafy green creature into its new home. After rubbing the gritty soil off of my hands, I looked at Brian, a co-volunteer and nonverbal 20-year-old with autism, who extended his arm for a high-five. In the year that I’ve been working with him, I’ve watched him revel in planting, nurturing, and eventually harvesting his veggies, especially the grape tomatoes, which we enjoy eating fresh off the vine! Upon walking to the next row of hollowed cavities, we were not contemplating the lengthy work that lay ahead, but rather, we sought to liberate the helpless lettuces, imprisoned in produce cartons that were too small for them to grow in. Finally, after taking a step back to admire the day’s last plant, my chest swelled as a wave of contentment flushed through my body.
My love for gardening began when I moved to Georgia during my sophomore year. In the time I’ve spent learning how to garden, I’ve developed an affinity for watching my vegetables grow to maturity, eager to be harvested and sold at the Saturday market. Though many see gardening as tedious busywork, I find it meditative, as I lose track of time while combining peat moss and soil in the garden’s compost mixer. Saturday morning garden work has become a weekend ritual, ridding me of all extraneous responsibilities. My body goes into autopilot as I let my mind wander. I don’t actively FOCUS on focusing, but rather I observe myself internally digest the week’s events. I’m a bystander to fireworks of thought that explode in my mind as my perception of important matters becomes trivial. Sometimes, it’s the physics midterm that suddenly seems less daunting or the deadlines I need to meet for my Spanish project that push back farther. Other times, I contemplate alternative endings to conversations or make perfect sense of the calculus answer that was at the tip of my tongue in class.
I met Brian, a close friend of mine who also basks in the tranquility of nature, through my gardening endeavors. While we aren’t able to communicate verbally, we speak the language of earth, water, peat, and seedlings. He doesn’t speak with words, but his face tells stories of newly found purpose and acceptance, a pleasant contrast to the typical condescension and babying he feels by those who don’t think he’s capable of independent thought.
Throughout my time in the garden with Brian, I began to understand that he, like everyone, has a particular method of communicating. There are the obvious spoken languages, body languages, facial expressions, and interactions we a day-to-day basis that reflect who we are and communicate what we represent. Brian expresses himself through various manifestations of unspoken language that he uses to signal how he feels or what he wants. But the nuanced combinations of different methods of communicating are oftentimes overlooked, raising a barrier to mutual understanding that prevents one from being capable of truly connecting with others. I began to understand that in order to reach people, I have to speak in their language, be it verbally or otherwise. Working with Brian over the past year has made me more aware that people can have difficulty expressing themselves. I found that I can positively lead people if I can communicate with them, whether on the track or in my Jewish youth group discussions. As I move into the next phases of my life, I hope to bring these skills with me because, in order to effectuate positive change in my community, I learned that I must speak in the language of those around me. Those are the words Brian taught me.
College essay example #14
This student was accepted at Brown University.
It felt like I threw myself out of a plane without a parachute. My eyes firmly shut, I feared for my life as I plummeted towards the ground. In hindsight, perhaps half coming out at a public restaurant wasn’t the brightest idea. Then again, living as the half-closeted queer kid meant that I was all too familiar with intimidating situations.
I asked my mom: “What would you do if I had a girlfriend?” She instantly replied that she couldn’t understand. Immediately, my heart dropped and the emotional free fall began. She explained that Americans choose to be gay for personal enjoyment, which in my Korean culture is an attitude that is severely frowned upon. I sat there like a statue, motionless and afraid to speak, blindly hurtling towards a hard reality I hadn’t expected. Rejection cut me deeply and I started to feel the itch of tears welling in my eyes, yet I had to contain myself. I couldn’t let the pain seep through my facade or else she would question why I cared. All I could do was keep looking down and shoveling food into my mouth, silently wishing I could just disappear. That night, I realized it would be a long time before I could fully come out to my mom. My eyes tightened as I continued to fall.
In the following weeks, I started noticing how discomfort played a natural part in my life. I recognized the anxious reactions of my classmates as I argued with my Christian friends when they said my queerness is a sin. I observed the judgmental glances my mentors gave me as I passionately disagreed with my conservative lab mates over my sister’s abortion. Eventually, my friends decided to censor certain topics of discussion, trying to avoid these situations altogether. I felt like vulnerability was the new taboo. People’s expressions and actions seemed to confine me, telling me to stop caring so much, to keep my eyes closed as I fall, so they didn’t have to watch.
Had others felt uncomfortable with me in the same way I had felt uncomfortable with my mom? Do they feel that our passions might uncover a chasm into which we all fall, unsure of the outcome?
Perhaps it was too raw, too emotional.
There was something about pure, uncensored passion during conflict that became too real. It made me, and the people around me, vulnerable, which was frightening. It made us think about things we didn’t want to consider, things branded too political, too dangerous. Shielding ourselves in discomfort was simply an easier way of living.
However, I’ve come to realize that it wasn’t my comfort, but rather, my discomfort that defined my life. My memories aren’t filled with times where life was simple, but moments where I was conflicted. It is filled with unexpected dinners and unusual conversations where I was uncertain. It is filled with the uncensored versions of my beliefs and the beliefs of others. It is filled with a purity that I shouldn’t have detained.
Now, I look forward to tough conversations with a newfound willingness to learn and listen, with an appreciation for uncertainty. I urge others to explore our discomfort together and embrace the messy emotions that accompany it. I try to make our collective discomfort more navigable. Since that dinner, my relationship with my mother is still in free fall. It’s dangerous and frightening. Thankfully, the potentially perilous conversations I’ve had with my friends has given me a newfound appreciation for my own fear. I’ll admit, part of me still seeks to close my eyes, to hide in the safety I’ll find in silence. Yet, a larger part of me yearns to embrace the dangers around me as I fall through the sky. I may still be falling, but this time, I will open my eyes, and hopefully steer towards a better landing for both my mom and me.
Titanium oxide helps perovskite solar cell reach 16.8% efficiency
A group of Japanese researchers have used anatase and brookite, which are two different variants of titanium dioxide, to improve the efficiency of a perovskite-based solar cell. The use of the two minerals is said to considerably improve the control of the electron transport out of the perovskite layer.
Image: Kanazawa University
Scientists at Japan’s Kanazawa University are seeking to improve the performance of perovskite solar cells by using two special kinds of titanium oxide, anatase and brookite.
In particular, they claim to have reached a conversion efficiency of 16.82% in a perovskite cell by applying a brookite layer made of water-solute brookite nanoparticles on an anatase layer. This, according to them, enables to improve the transport of electrons from the center of the cell to its electrodes, while also preventing charges from recombining at the border between the perovskite material and the electron transport layer.
“Together, both these effects allow us to achieve higher solar cell efficiencies,” said the research coordinator, Md. Shahiduzzaman.
The research team stressed that the anatase layers were created by spraying solutions onto glass coated with a transparent electrode that was heated to 450 °C, while the brookite layers were produced with water-soluble brookite nanoparticles, as this kind of ink is more environmentally friendly than conventional inks.
The scientists have also made comparisons between different options as using anatase or brookite separately or combination layers with anatase on top of brookite or vice-versa. The also highlighted how previous researchers had discovered that thin layers of titanium oxide are both transparent and able to transport electrons to the electrode.
Earlier in March, a group of scientists from the U.S. Department of Energy’s (DOE) Argonne National Laboratory showed the research results into the replacement of titanium dioxide in the manufacture of solar cells.
Scientists around the world have looked into substituting the lead in common perovskite designs with various materials, including titanium, tin and bismuth.
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Emiliano joined pv magazine in March 2017. He has been reporting on solar and renewable energy since 2009.