Electrophoretically Deposited MoSe₂/WSe₂ Heterojunction from Ultrasonically Exfoliated Nanocrystals for Enhanced Electrochemical Photoresponse

Abstract

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 2 , WSe 2 , and MoSe 2 /WSe 2 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 2 and WSe 2 nanocrystals in the formation of the MoSe 2 /WSe 2 heterojunction. Because of superior absorption of MoSe 2 /WSe 2 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.

Solution-Processed Uniform MoSe2–WSe2 Heterojunction Thin Film on Silicon Substrate for Superior and Tunable Photodetection

“…The dispersed nanocrystals acquired charge on the surface, and under the influence of applied electric field its transport toward the oppositely charged surface to form a film. Electrophoretic deposition (EPD) method is driven by several advantages, e.g., simplicity, reproducibility, cost-efficiency, controlled thickness, homogeneity, and high packaging density. , EPD methods do not involve a high-temperature environment, allowing flexibility in choosing the substrate materials . EPD is applicable to a large diversity of materials and plays a key role in the fabrication of various optoelectronic devices.…”

Large Tunneling Magnetoresistance in VSe2/MoS2 Magnetic Tunnel Junction

“…Two-dimensional (2D) van der Waals (vdW) materials, with the strong covalent intralayer bonding and the weak vdW interlayer interaction, exhibit novel properties and various advantages. [1][2][3][4] Recently, the investigations on ferromagnetic vdW materials make great progress [5][6][7][8] and experimental advances have demonstrated that ferromagnetic order can persist in the ultrathin atomic limit. 9,10 Monolayer CrI 3 has been reported to be an Ising ferromagnet with perpendicular magnetic anisotropy (PMA) and 45 Kelvin Curie temperature.…”

Harnessing Ionic Power from Equilibrium Electrolyte Solution via Photoinduced Active Ion Transport through van‐der‐Waals‐Like Heterostructures

“…Toward next-generation light-to-ionic energy conversion, van der Waals heterostructures, composed of two or more types of restacked 2D materials, become a source of inspiration. [25] So far, various binary (MoS 2 /WS 2 , [26] MoSe 2 /WSe 2 , [27] MoS 2 / WSe, [28] graphene/MoS 2 , [29] and graphene/h-BN [30] ) or even ternary (MoS 2 /WS 2 /WSe 2 [31] and graphene/MoS 2 /WS 2 [32] ) van der Waals heterostructures are investigated for optoelectronic and photovoltaic applications. Among them, transition metal dichalcogenides (TMDs) establish themselves as representative photoactive materials with strong light-matter interaction and wide spectral absorption.…”