Flexible solar cells based on stacked crystalline semiconductor nanomembranes on plastic substrates

We report here experimental demonstration of flexible solar cells based on crystalline semiconductor nanomembranes (NMs) transferred onto flexible PET (polyethylene terephthalate) substrates. For 1 micrometer thick p-i-n InP NMs, we obtained an open circuit voltage of 0.68 V and power efficiency of 1.5% from the photovoltaic solar cells. The results agree very well with the anticipated thin film InP solar cell performance considering the low absorption in very thin InP NMs. The efficiency remains unchanged for bending radii greater than 42 mm. It drops to 50% of its original value at a bending radius of 32 mm. The results demonstrate a promising future for such a new type of cost effective flexible thin film solar cells, based on crystalline semiconductor membranes.