Cuprous sulfide on Ni foam as a counter electrode for flexible quantum dot sensitized solar cells†
Abstract
The development of a highly efficient stretchable counter electrode (CE) for quantum dot sensitized solar cells (QDSCs) is still challenging. In this work, a flexible Cu/Ni film has been pre-prepared via a novel redox reaction between Ni foam and Cu ions. Further, a flexible Cu2S/Ni CE was fabricated for the first time by sulfidation of the Cu/Ni film. A high photovoltaic conversion efficiency (PCE) of 8.94% for a model CdSeTe QDSC composed of the flexible Cu2S/Ni CE and a glass based photoanode was obtained, with the performance being strongly attributed to the excellent catalytic activity, high conductivity and good adhesion between Cu2S and Ni foam. Furthermore, flexible photovoltaic devices constructed using the as-prepared bendable Cu2S/Ni CE as well as a TiO2 based plastic photoanode have also been assembled with the highest PCE of 3.55%. Satisfactory mechanical properties and stability after repeated bending have also been achieved.