MoSe 2 nanoflowers as a counter electrode for quantum dots sensitized solar cells

Layered transition metal dichalcogenides hold tunable and promising photoelectrochemical properties. MoSe 2 is a potential candidate of the transition metal dichalcogenide family, which attracted interests of various fields such as photocatalytic, electrocatalytic, energy storage, sensing and optoelectronic applications. MoSe 2 demonstrates high surface activity and strong absorption contributing to its enhanced electrocatalysis properties. The conversion from bulk structure to 2D nanosheets of MoSe 2 increases the bandgap from 1.1 eV (indirect) to 1.55 eV (direct) analogous to Si, leading to wide utilization in optoelectronics. Herein, we have developed flowers-like nanostructured molybdenum diselenide (MoSe 2 ) via hydrothermal method and studied their efficiency as counter electrode (CE) in TiO 2 /CdS/ZnS-based quantum dot-sensitized solar cells (QDSSC). The electrical conductivity studies indicate that the MoSe 2 CE has higher electrical conductivity as compare to the conventional CuS CE as observed in this study. Accordingly, the power conversion efficiency of the developed QDSSC with MoSe 2 as a CE is found to be 2.08%, while it is only 1.09% when CuS is used as the CE. The obtained efficiency of MoSe 2 is attributed to their enhanced crystallinity along with 2D structure, high surface area and conductivity properties.