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.