Ca-doped CuSe/graphene oxide nanocomposite as a counter electrode for improving quantum dot-sensitized solar cell performance

Copper selenide (CuSe) is one of the most important counter electrodes (CEs) in high-efficiency, quantum dot-sensitized solar cells (QDSSCs). In this work, we investigated the effect of Ca ion incorporation into the CuSe layer on the photovoltaic performance of quantum dot-sensitized solar cells. Metal ion-doped CuSe was deposited by the successive ionic layer adsorption and reaction (SILAR) method on the FTO substrate. Ca-CuSe/GO counter electrode-based QDSSC exhibits power conversion efficiency (η) of ۳.۱۰%, which is higher than the ۲.۰۶% efficiency of copper selenide (CuSe). Electrochemical impedance spectroscopy results show that by the changing counter electrode from CuSe to M-CuSe/GO, the charge transfer resistance is reduced at the counter electrode/electrolyte interfaces and therefore, current density increase from ۱۶.۷۴ mA/cm۲ to ۱۹.۴۶ mA/cm۲. M-CuSe/GO counter electrode can be considered as a promising alternative to the noble CuSe counter electrode in QDSSCs.