Electrophoretically Deposited MoSe 2 /WSe 2 Heterojunction from Ultrasonically Exfoliated Nanocrystals for Enhanced Electrochemical Photoresponse

• Published in: ACS applied materials & interfaces Vol. 11; no. 4; pp. 4093 - 4102
• Main Authors: Patel, Alkesh B, Machhi, Hiren K, Chauhan, Payal, Narayan, Som, Dixit, Vijay, Soni, Saurabh S, Jha, Prafulla K, Solanki, Gunvant K, Patel, Kireetkumar D, Pathak, Vivek M
• Format: Journal Article
• Language: English
• Published: United States 30.01.2019
• Subjects: WSe2; electrophoresis; self-powered electrochemical photodetector; liquid-phase exfoliation; heterojunction; MoSe2
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.8b18177

The solar response ability and low-cost fabrication of the photoanode are important factors for the effective output of the photoelectrochemical system. Modification of the photoanode by which its ability to absorb irradiation can be manipulated has gained tremendous attention. Here, we demonstrated the MoSe , WSe , and MoSe /WSe nanocrystal thin films prepared by the liquid-phase exfoliated and electrophoresis methods. Atomic force microscopy and high-resolution transmission electron microscopy show that the liquid exfoliated nanocrystals have a few layered dimensions with good crystallinity. Scanning electron microscopy demonstrated uniform distribution and randomly oriented nanocrystals, having a homogeneous shape and size. X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectra confirm the equal contribution of MoSe and WSe nanocrystals in the formation of the MoSe /WSe heterojunction. Because of superior absorption of MoSe /WSe heterojunction in the visible region and type-II heterojunction band alignment, in situ measurement of heterojunction electrode shows almost 1.5 times incident photo-to-current conversion efficiency and photoresponsivity in comparison to individual material electrodes. Our result clearly indicates the influence of heterojunction formation between liquid exfoliated nanocrystals on effective separation of photogenerated exciton and enhances charge carrier transfer, which leads to the improvement in photoelectrochemical performance. Liquid exfoliated nanosheet-based heterojunction is attractive as efficient photoanodes for the photoelectrochemical systems.