In situ fabrication of Cu2−xSe networks nanostructure counter electrode based on Ti substrate via sacrifice template method for quantum dot sensitized solar cells

Abstract

An efficient and simple strategy is designed for the synthesis of Cu2−xSe with two different morphology, including networks nanostructure and nanosheets structure, based on Ti substrate using a sacrificial template method (CuTi2S4 and Cu). The corresponding Cu2−xSe/CuTi CE and Cu2−xSe/Cu CE could be applied as counter electrodes (CE) for quantum dot sensitized solar cells (QDSCs). As a result, the cell fabricated by Cu2−xSe/CuTi-4 CE exhibits a photoelectric conversion efficiency (PCE) of 6.25% under 1 sun (100 mW/cm2) illumination as compared to that of Cu2−xSe/Cu CE (4.83%). According to transient photocurrent (TPC) result, the improving photovoltaic performance could be attributed to the improving electrocatalytic activity towards polysulfide electrolyte as compared to Cu2−xSe/Cu CE. These results are in accordance with the EIS analysis and Tafel polarization curve results for symmetrical cell. In addition, the outstanding stability of Cu2−xSe/CuTi CE could be further proved by cyclic voltammetry (CV) test. In conclusion, the Cu2−xSe/CuTi CE could be a promising material and the applications in solar cells.