A facile and controllable electrochemically fabricated nonstoichiometric MoOx film for novel opto-electronic devices

Non-stoichiometric transition metal oxides have received considerable attention because of their excellent optical and electrical properties for novel high performance opto-electronic devices or photocatalysis, among which MoOx was one promising candidate. However, few studies have been focused on its evolution under different controlling parameters and ambient conditions. In this work, we report a facile electrochemical method for smooth and uniform non-stoichiometric MoOx films, with effective control of the morphology, chemical composition and microstructure of molybdenum simply by a few physical/chemical parameters. The modification of roughness, crystallinity, oxygen vacancy concentration can play an important role in their opto-electronic performances, e.g. in the perovskite solar cells. As a result, a conversion efficiency of 9.20% could be obtained by control of oxygen vacancies and crystallinity and could be further improved with the change of transparencies. Furthermore, its wetting properties could be significantly influenced for further applications, especially for fabrication of novel detectors and perovskite solar cells.