Enhanced performances of flexible ZnO/perovskite solar cells by piezo-phototronic effect

In this work, piezoelectric ZnO microwire was utilized to form heterojunctions with perovskite as flexible photovoltaic devices, and has a power conversion efficiency of 0.0216%. By employing the piezo-phototronic effect, the strain-induced piezoelectric polarization charges at the vicinity of ZnO/perovskite interface can modulate the transport and separation processes of photo-generated carriers within the photovoltaic device and enhance the performances of ZnO/perovskite solar cells. The corresponding open-circuit voltage (V_oc), short-circuit current (I_sc) and efficiency of the solar cells were improved by 25.42%, 629.47% and 1280% (from 0.0216% to 0.298%) through piezo-phototronic effect, respectively. Physical working mechanism behind the observed results was carefully investigated by using energy band diagram. This study provides a promising approach to effectively enhance the overall performances of flexible solar cells for various applications.