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Summer 2013 Blog - Heather Hughes

Heather Hughes is spending nine weeks in Taiwan working at Academia Sinica. 

August 4, 2013

What a summer! Friday was my last day in the lab and I can hardly believe nine weeks has already passed. Yet, reflecting on all that I have learned and done during this time makes it feel like I have been in Taiwan for much longer than one short summer. I have had an exceptional experience with Cal Energy corps and am sad to see it come to a close.

I spent my last few days in the lab wrapping up my experiments, preparing for the Cal Energy Corps symposium in October, and organizing my experimental materials and results so that they can be easily accessed and understood by other members of the lab in the future. On Thursday I attended a poster presentation featuring the research of scientists from various different labs at Academia Sinica. Here, I was able to learn a bit about how best to prepare for my own poster presentation, as well as learn about other research within Academia Sinica. On Friday I relabelled and reorganized all of the electrolytes that I prepared this summer and enjoyed seeing all of my hard work from the summer nicely organized and all in one place. Hopefully these electrolytes can now be used in future related experiments. With all of these tasks completed my lab-mates took me out to a delicious good-bye lunch and my time at Academia Sinica was complete. I hope to continue working with dye-sensitized solar cells at a lab in Berkeley and intend to return to Taiwan within the next year or two because I thoroughly enjoyed both of these aspects of my experience and am not ready to be done with them.

I would like to express my sincere gratitude to Cal Energy Corps including its facilitators and its supporters for making this program possible. The opportunities available through Cal Energy Corps played a notable role in my decision to attend UC Berkeley. This program emphasizes UC Berkeley’s commitment to involving undergraduate students in the energy solutions of the future. I feel so lucky to have had the chance to be a part of this program and encourage any interested students to apply. I would also like to thank Professor Lin for welcoming me in to his lab, Dr. Hsu for guiding me throughout my research internship, and the rest of my lab-mates for their nonstop hospitality and support. Thank you for reading

July 31, 2013

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Heather and all of her lab-mates at a special lunch hosted by the graduating students to thank Professor Lin.

The exhilaration and rush that I experienced as we boarded our flight to Hong Kong and departed just in time to avoid the incoming typhoon appropriately set the tone for the past two and a half weeks. With my time in Taiwan quickly dwindling, time is precious and I must act quickly to finish all of the experiments I would like to perform in the lab, explore the parts of Taiwan I haven’t visited, and connect again with the many wonderful people that I have met.

Visiting Hong Kong was a very cool experience and provided an interesting juxtaposition to Taiwan. James and I showed Sofia Hamilton (Cal Energy Corps researcher in Hong Kong) around Taipei last month and she returned the favor by acting as our gracious host in Hong Kong. We enjoyed visiting many of the famous sights as well as hanging out with some Hong Kong locals and eating traditional Hong Kong dim sum.

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Heather and one of her lab-mates enjoying a Green Island specialty: mango snow ice with Green Island seaweed.

Back in the lab on Monday, I continued preparations for my presentation and attempted to do some preliminary testing using a cobalt-based electrolyte in combination with the D5 dye that I have been working with. Cobalt-based electrolytes are currently a hot topic in dye-sensitized solar cell research and may replace traditional iodine-based electrolytes in the future. I was thus excited when Dr. Hsu proposed that I try combining the cobalt-based electrolyte he had produced with the D5 dye. Unfortunately, I encountered some technical difficulties and was not able to yield any useful results before I had to carry out my presentation and return back to my main research focus.

I was relieved to find that my presentation was received well, Professor Lin even joking with me that I “passed” my “midterm evaluation.” Using the feedback that I received from Professor Lin, Dr. Hsu, and my lab-mates, I decided to spend the remainder of my time in the lab further optimizing the electrolyte for the D5 dye. There are nearly 90 electrolyte combinations possible from varying the concentrations of the three main electrolyte components that would be useful to evaluate. In the first part of my testing I varied the three main electrolyte components independently to evaluate fourteen of the nearly 90 electrolyte possibilities.

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Sofia, James, and Heather in front of the world’s largest sitting buddha statue, located in Hong Kong.

While time and resource constraints restrict me from looking at all of the electrolyte possibilities, I will try to detect other key trends through testing a few more select compositions. The experiment involves four stages of testing, each stage building on what is discovered in the stage previous. I will look more closely at whether substituting one of the electrolyte components, 4-tert-butylpyridine (tBP), with N-methylbenzimidazole (nmbi) or guanidinium thiocyanate (GuSCN) additive can improve cell efficiency. Additionally, I will explore the effect of using GuSCN in conjunction with tBP or NMBI in the electrolyte. In performing this final experiment, I hope to obtain an even clearer picture of how the electrolyte can be best matched to the D5 dye as well as perhaps dyes of similar structure.

The weekend adventures continued as I traveled with my lab-mates to Taidong and Green Island for a “lab field-trip.” A small island off of the Southeast coast of Taiwan, Green Island is a former prison with a rich history and plentiful natural beauty. Here, we snorkeled, visited the world famous Zhaori hot springs, explored the island by scooter, and spent some quality time getting to know each other better. This trip gave me the chance to intensely practice Chinese, learn more about the backgrounds and aspirations of my lab-mates and further experience Taiwanese culture.

It’s hard to believe that we have less than one week to go. I will spend the rest of my time in the lab finishing up my experiments and preparing the discussion that will be included in the poster for the Cal Energy Corps Symposium in October.

July 12, 2013

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Heather’s set-up for the last part of the dye-sensitized solar cell fabrication process.

As I hoped for at the end of my last blog post I have some exciting testing results to report on this week.  I have spent the bulk of the last two weeks in the lab fabricating dye-sensitized solar cells, testing the cells, and processing the data in excel. I have become faster and more consistent with fabricating the cells and now have a better understanding of what exactly the tests are evaluating and what the results indicate. While my initial tests looked at three different dyes, stability issues with the dyes led to the conclusion that I should narrow my focus to just one of the three dyes. The dye that I am looking at, referred to as D5 in the lab, seemed like a good choice because its properties suggest that out of the three dyes it should yield a dye-sensitized solar cell with the highest efficiency, yet in Dr. Hsu’s initial tests it performed the worst. This result indicates that the electrolyte used in those initial tests is a bad match for this dye and an electrolyte with better-matched energy levels might help this dye demonstrate its full potential.

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Heather getting ready to go paragliding.

The type of iodine electrolyte that I am looking at has three main components: iodine (I2), lithium iodide (LiI), and tert-butylpyridine (tBP). Each of these chemicals performs a different function in the electrolyte. In order to optimize the performance of the electrolyte with the D5 dye I performed three multi-part tests with each test manipulating the concentration or composition of one of the three electrolyte components. Not only did these tests lead to a preliminary conclusion about what electrolyte composition is the best match for the D5 dye, the trends in the results also give better insight into how exactly the concentration of each of these components affect electrolyte performance. These trends may be able to be used to make better initial predictions as to what electrolyte composition is the best fit for other dyes.

I will present my progress and results to the lab and my professor in a “midterm report” during our weekly meeting this Tuesday. I am nervous for the presentation yet looking forward to getting some feedback on how the data looks and how I should proceed. There are a few different routes I can take in the next stage of my research. Depending on the feedback I get on Tuesday, I may chose to do further testing on the optimized electrolyte, go back and determine the optimized electrolyte composition for the other two dyes from my initial tests, or begin testing on a different electrolyte entirely.

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Tea sampling at Heather’s lab-mate Mark’s home.

While you might think that after being here for over a month new experiences would start to become harder to come by, it feels as if just the opposite is true. During my fifth weekend here, Sofia Hamilton, a fellow Cal Energy Corp participant working in Hong Kong, came to visit. As James and I showed Sofia around a few of our favorite spots I realized that I have come to feel very at home in Taipei and like a bit like more of a local than a visitor. With Sofia we went paragliding, attended a small music concert, visited Taipei 101 (the third tallest building in the world and a great engineering marvel), and were treated to an evening of private tea sampling at my lab-mate Mark’s home (his family grows and sells tea).

This past weekend was perhaps the most exciting one yet. On Friday night we met up with Taipei’s Fixie Bike Club. This club is a huge group of young fixed gear bicycle enthusiasts that we stumbled upon the week before while they were preparing for their weekly ride. We rented bikes using the city bike-share system and had the most exhilarating time attending an informal bike showcase/completion, eating at a night market, and riding all throughout Taipei with the group from midnight until dawn. In light of the past month spent doing research on alternative energy it was cool to see how this group has turned energy efficient transportation into such a fun and uniting hobby.

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Heather, James, and Sofia with the Taipei Fixie Bike Club.

Saturday we attended a pool party and met some of the friendliest and most interesting people I have encountered, some of them locals and many from all different parts of the world. I really enjoy meeting other internationals and learning about what brings them to Taiwan as it is not as well known of a destination as its neighbors China or Japan. Typhoon permitting, James and I are headed to Hong Kong this weekend to visit Sofia. Between that trip and my presentation on Tuesday the next week is certain to be another action-packed one.

June 28, 2013

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Heather performing electrochemical testing on the electrolytes.

The past month has been one of significant learning and growth. Never before have I had the opportunity to invest so much time and energy into one narrow academic topic and the experience has been immensely enjoyable. As I briefly described in my last post, the main focus of my work is to optimize the performance of dye-sensitized solar cells by altering the composition of the electrolyte within the cell. There is no single best electrolyte composition because the performance of the cell is influenced by how compatible the electrolyte is with the specific dye being used.  Optimizing cell performance relies on identifying the dye-electrolyte combination in which the energy levels are best matched. In my current work I am looking at three novel dyes synthesized by a graduate student in our lab and trying to determine which of six differently concentrated electrolytes is the best match for each of these three dyes.

During week three I was able to complete the fabrication of my first set of dye sensitized solar cells and test their performance. Cell fabrication was very exciting because I began the process with just a plain sheet of glass and after performing a variety of processes I ended up with a set of hand-made fully functioning solar cells. While very rewarding, this process was also a bit challenging due to the lack of mechanical equipment and protocol to help ensure consistent cell fabrication.

Although some prepared materials can be purchased, our lab and many labs around the world do the fabrication almost entirely from scratch, using materials produced in the lab and makeshift fabrication apparatuses. During this process I often found myself concerned with how my inability to roll, mix, measure, and scrape various materials onto and off of the glass exactly the same every time would impact my results. When I asked Dr. Hsu, the postdoc who has been teaching me the fabrication process, about this issue, he said that this fabrication method actually involves very little error and the results are usually easily reproducible. He also later mentioned that when he first got started it took him a number of cell fabrications before he began getting consistent results and achieving high cell efficiencies.

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Left to right, Heather’s eighteen dye-sensitized solar cells, testing one of the dye-sensitized solar cells, and the three dyes and six electrolytes that Heather is evaluating.

Dr. Hsu does most of the cell fabrication and testing work in the lab and fabricates cells nearly every day while the other students and postdocs work primarily on synthesizing the dyes used in the cells. I think having just one person fabricate the cells helps ensure that each set of cells is fabricated nearly exactly the same and performance is optimized. Regardless, during the process I often found myself thinking that it might help reduce fabrication and testing time as well as decrease the chance of human error by introducing some simple mechanical apparatuses into the process. As a mechanical engineering major this type of project interests me and is perhaps something that I will pursue in the lab if time and resources permit.

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Heather with one of her dye-sensitized solar cells.

By the end of the fabrication process I had eighteen different dye-sensitized solar cells, each composed of one of three different dyes combined with one of six different electrolytes. I then tested the cells and processed the raw data in order to determine performance indicators such as open circuit current, short circuit current, fill factor, and cell efficiency. As the week concluded I was discouraged to learn that the results from my control cells did not match with the results found when these cells were previously evaluated in our lab. This mismatch indicated that something had gone wrong in the fabrication or testing process and my entire data set could not be used. On Monday, a quick examination of my cells by Dr. Hsu revealed where the error occurred and I immediately got to work on refabricating and testing the cells. I am currently processing my new set of data and hoping it yields more useful results.

Throughout this process I was also preparing for a review of two academic papers, which I presented for our lab group on Wednesday. The two papers that I presented examined alternative materials for cathodes in dye-sensitized solar cells. This is an area that is not heavily studied in our lab but is still strongly related to the work that we do. Preparing for this presentation helped me get an even better understanding of how dye-sensitized solar cells work and provided a bit more insight into the electrolytes that I have been testing. While a bit nerve-racking, it was fun to actively participate in our weekly lab meeting instead of just observing and this mini-presentation was good preparation for when I present my work in meeting at the conclusion of my time here in August.

Besides learning in the lab, James and I have continued to explore all that Taiwan has to offer. During our third weekend here I enjoyed dining at an all you can eat (in two hours) Thai restaurant with fifteen of my lab-mates, visiting the zoo (not too different from zoos in America), riding the Maokong gondolas up to the mountains to learn about tea production in Taiwan, and visiting the National Palace Museum. Last weekend, James and I traveled by train to a beautiful town on the East Coast named Hualien. In Hualien we hiked through the world famous Taroko Gorge, sampled distinctive coastal cuisine, visited the beach, and more. The character of Hualien was a bit more relaxed than that of Taipei. I look forward to experiencing the other unique characters that different areas in Taiwan have to offer. Hopefully in my next post I will have some exciting test results to report as well!
June 13, 2013

“Wo yao qu zhong yan yuan,” I slowly explained in Mandarin Chinese to the cab driver, hoping he would understand my request to be taken to Academia Sinica, my home and workplace for the next two months. He smiled, nodded his head, and we were off. I had successfully completed my first task (getting back from the airport) and my summer adventure in Taiwan had officially begun!

Since my arrival nearly two weeks ago, I have had an exceptional time learning and exploring both inside and outside the lab. At Academia Sinica I am working under Professor Jiann-T’suen Lin in the Institute of Chemistry on creating new materials for solar cells. Specifically, I am working on the fabrication of dye-sensitized solar cells and striving to optimize the efficiency of these solar cells through altering the composition of the electrolyte within the cell.

The first week involved becoming adjusted to the lab through getting to know my lab-mates, safety training, ample reading of background material, and observing the fabrication of dye-sensitized solar cells. I also enjoyed sitting in on the weekly lab group meeting and practicing my Chinese while trying different local restaurants with my lab-mates during our lunch break. Most of the people in the lab are graduate students or post-docs so have a lot of knowledge regarding college and energy to share with me. They have been immensely welcoming and friendly, so friendly in fact that when I mentioned that I was going to try to go to the beach over the weekend, they insisted on taking me themselves.

I traveled with James, the other Cal Energy Corps student staying at Academia Sinica, and two of my lab-mates by train to Fulong beach. Here, in addition to enjoying the beach, we got to experience the Fulong International Sand Sculpture Festival. Besides the beach, James and I have done a great deal of exploring including visiting two different night markets, rowing dragon boats along the Keelung River, and hanging around downtown Taipei where we enjoyed checking out Taipei 101, spending time at the world famous Islight book store, and chowing on Mango shaved ice. We have begun to get a hang of the public transit system (it’s great!) and have sampled lots of the different types of cuisine that Taiwan has to offer in the small family-run restaurants that line the main street near Academia Sinica and at the night markets.

This week has been especially exciting in all aspects. Under the guidance of a post-doc that I will be working closely with, I have begun fabrication of my very own set of dye-sensitized solar cells which I will soon use to begin testing the efficiency of different electrolyte solutions. I also got to learn about and help evaluate the efficiency of organic photovoltaic cells, another focus area within the lab.

On Wednesday we celebrated the Dragon Boat Festival with a community of international students who are also living and working at Academia Sinica. James and I traveled with the group to a Buddhist temple where a ritual was performed and we dined on zongzi, a Chinese snack that consists of rice stuffed with different fillings and wrapped with bamboo leaves that is traditionally eaten on the day of the Dragon Boat Festival. We then walked down to the river and spent the day enjoying the festivities, making new friends, and cheering on team Academia Sinica in the race. Things are off to a great start and I will report back soon with more scientific and cultural adventures!

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