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 commercial development of dye-sensitized solar cells (DSSCs). Herein, we utilize a simple and mild H2O2 etching strategy to introduce Mo vacancies on the surface of MoS2 thin film and cause the crystal phase change from 2H to 1T. By systematically adjusting the etching time, temperature, and solution concentration, the optimal concentration of Mo vacancies was obtained. 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. Meanwhile, 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 about regulating vacancy and phase induced by etching, especially in indoor low light environment. Furthermore, the prepared flexible MoS2-60 s CE also possessed prominent electrochemical stability, bending durability and uniform electrocatalytic activity with the size of 4.5 × 5 cm. The significantly enhanced effect is mainly attributed to the synergistic effect of Mo vacancy and phase. Moreover, the transmittance of MoS2 CE after etching has been significantly improved, which has the potential for application in transparent DSSCs. In this article, the CE with high response in simulated indoor light, good stability, flexibility and transparency was prepared, which expanded the application scenario of DSSCs and promoted its commercial application.