Investigation of transparent electrodes and transparent/opaque a-Si:H solar cells for indoor photovoltaics

Transparent and opaque hydrogenated amorphous silicon solar cells (a-Si:H) with various transparent electrodes are fabricated for indoor photovoltaics to supply power to Internet of Things devices. The performances of fabricated cells are investigated to evaluate the transparent electrode structures. The highest efficiency (6.05%) and highest average transmittance (24%) in the visible range are obtained with a transparent a-Si:H solar cell having single front and rear GZO electrodes, while the best efficiency is 9.29% with an opaque a-Si:H solar cell. Under LED indoor light, the best efficiencies are 5.12% with the opaque solar cell and 5.75% with the transparent solar cells.