Project Summary

Plants can use green chlorophyll and sunlight to produce energy.  Can we harvest solar energy with fruit dyes to generate electricity?  Intrigued, I began exploring fruit dye solar cells.  The cells were built following the Gratzel method.  Sunlight excites fruit dyes to release electrons that are transferred through a nanocluster film of titanium oxide out to the circuit as electricity.  After 14 trials, I was able to improve the construction procedure and achieve good reproducibility on the solar cell performance. 


My homemade raspberry dye solar cell (10 cm2) under direct sunlight generated 0.5 volts and 4 mA of electricity.  Solar cells made of red raspberry dyes generated the highest voltage and current, following closely by those made of purple blackberry and red cranberry dyes.  Dyes from dark yellow mango, light yellow pineapple, and bright green broccoli did not work as well in generating electricity, only 5-10% of the raspberry case.  The red/purple dyes were more efficient. 


The effects of light strength and cell area on the solar cell performance were tested for potential applications.  The produced currents increased linearly with the light strength and cell area, indicating the potential for use under partial sun and the possibility to be scaled up for applications.    


These fruit dye solar cells generated a power of 2 watts/m2, corresponding to a conversion efficiency of 0.2% for the solar power.  It demonstrates the potential of using fruit dyes and sunlight to generate electricity.  It is a new, clean, renewable, potentially inexpensive energy. 





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