Solar cells made with materials from fruit dye and sunscreen are a promising replacement to silicon.

AJAS · 2022 Engineering

Alex Devine

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Overview

Traditional silicon solar panels are too expensive to be widely implemented. While silicon is plentiful, manufacturing silicon into solar cells is a difficult and expensive process. This research sought innovative ways to improve the cost efficiency and environmental friendliness of solar energy. It is hypothesized that solar cells could be made with more cost-effective materials and still produce an equivalent amount of energy. Dye-sensitized solar cells replace silicon with zinc oxide or titanium dioxide, two materials commonly found in sunscreen, and fruit dyes from raspberries, blackberries, and blueberries. The fruit dye absorbs the light and converts it into electricity, and the zinc oxide or titanium dioxide transport the electrons through the cell. In the experiment, solar cells made with zinc oxide and titanium dioxide, three different fruit dyes, and different dye times (how long each cell is dyed) were tested for voltage under a lightbulb. Out of the 36 cells made, the most productive cell was a zinc oxide cell that was dyed in blueberry dye for 135 minutes, producing 0.53 volts of electrical potential. While these small-scale cells were still not as cost-effective as silicon solar cells, the improvement from previous research shows promise in dye-sensitized solar cells. In addition, this research helped identify additional material changes that might further improve results in the future.

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From the student

I love being outdoors and exploring new places. Whether hiking, biking, geocaching, kayaking, or anything in between, I always find time to be outside. I’ve been fortunate to travel to some amazing places like the glaciers in Alaska, the Great Barrier Reef, and the local metroparks. These experiences have nurtured my love for the environment and its beauty.

Unfortunately, my travels have also highlighted the effects of climate change. I’ve witnessed firsthand glaciers that are rapidly shrinking and coral reefs that have been bleached by rising water temperatures. Seeing our planet too quickly deteriorating from human interaction frightens me and has inspired my science research.

I began my research in the eighth grade. I knew that I wanted to do a project that would help fight climate change and preserve our environment, and one of the first ideas that came to mind was solar energy. Luckily, my high school had a solar array installed that could track its power output remotely, and so I began my first project by determining how the angle, temperature, and cloud cover affected the output of the solar panel. I thought the project was interesting, but I knew that in order to make a real impact with my research, I needed to move onto more innovative experiments that could yield more impactful results.

As I moved into high school, I began a new project by testing how effective different solar panels are at producing energy from different types of indoor light. The idea behind the project was that all of the energy used for lightbulbs was only used once. By collecting the used light with solar panels, the light would essentially be recycled. Again, this project was interesting, but I wanted to find a focus that could be more impactful.

In my sophomore year of high school, I found my focus. I had read about a different type of solar cells than silicon: dye-sensitized solar cells, which could be made with zinc oxide or titanium dioxide, two materials found in sunscreen, and raspberry, blackberry, or blueberry dye. I had already known that one of the largest challenges to implementing solar energy worldwide was the cost to produce them, and dye-sensitized solar cells provided a simpler and more cost-effective alternative. So, I started making my own dye-sensitized solar cell using zinc oxide and raspberry dye to learn the process and to see if it could be as cost-effective as a silicon solar cell. While this solar cell did not end up producing much energy or coming close to the cost-effectiveness of silicon solar cells, I learned how to make my own solar cell and was ready to hit the ground running the next year.

I decided to extend my ability to produce dye-sensitized solar cells by maximizing the cost-effectiveness during my junior year. I ramped up the production from 1 cell to 36 cells, so that I could test two different semiconductors, three different dyes, and three dye times. My solar cells were much more effective, with the best cell producing more than five times the voltage of my previous cell. With this project, I had my most successful science fair season yet, eventually being named as an AJAS Fellow, one of my proudest accomplishments.