Organic-inorganic hybrid solar cells are strong contenders for low-cost photovoltaics. Despite great effort to bring this product to market, fundamental device physics are still being uncovered. Recently, it has been observed that solar cells comprising of poly(3-hexylthiophene) (P3HT) and zinc oxide (ZnO) nanorods exhibit a 48% increase in efficiency under modest acoustic vibration [1]. Authors hypothesize this radical increase in efficiency is due to piezovoltage in ZnO nanorods, which reduces charge recombination. Though as of yet, there has been no meso-scale functional imaging of this new and exciting phenomenon. Using a combination of piezoresponse and conductive-probe atomic force microscopy, we correlate structural resonance of ZnO nanorods with improved charge separation in hybrid solar cells. We suggest photovoltaic design parameters to enhance charge collection in the presence of ambient vibration.
[1] S. Shoaee, J. Briscoe, J. Durrant, and S. Dunn, Advanced Materials, 2014, 26, 263