Strategic design of vacancies and phase in flexible MoS2 for boosting triiodide reduction performance

Abstract

Developing low-cost, efficient and flexible electrocatalysts is an important approach to promote the commercialization of dye-sensitized solar cells (DSSCs). Herein, we utilized a simple and mild H₂O₂ etching strategy to introduce Mo vacancies on the surface of the MoS₂ thin film and induce a crystal phase change from 2H to 1T. By systematically adjusting the etching time, temperature, and solution concentration, the optimal concentration of Mo vacancies was achieved. As a result, the optimized flexible CE (MoS₂-60 s) exhibited the highest power conversion efficiency (4.45%), which was increased by 33.24% compared to the untreated MoS₂ sample. Moreover, the PCE of MoS₂-60 s CE under simulated indoor light irradiation (1000 lux) was 24.33%, demonstrating its advantages for indoor PV applications. The above data proved the effectiveness of the strategy for regulating vacancies and phase changes induced by etching, especially in indoor low-light environments. Furthermore, the prepared flexible MoS₂-60 s CE also exhibited prominent electrochemical stability, bending durability and uniform electrocatalytic activity with a size of 4.5 × 5 cm. The significantly enhanced performance was mainly attributed to the synergistic effect of Mo vacancies and phase change. Moreover, the transmittance of the MoS2 CE after etching was significantly improved, showing potential for application in transparent DSSCs. In this article, the CE with high responsiveness to simulated indoor light, good stability, flexibility and transparency was prepared, which expands the application scenarios of DSSCs and promotes their commercial application.