Enhanced photoelectrochemical activity in the heterostructure of vertically aligned few-layer MoS2 flakes on ZnO

• DOI: 10.1016/j.electacta.2017.11.089
• Publication Date: 2017-11-14T15:47:00Z
• Authors: Tran Nam Trung; Dong-Bum Seo; Nguyen Duc Quang; Dojin Kim; Eui-Tae Kim
• Keywords: Photocurrent; Indium tin oxide; Chemical bath deposition

Abstract Vertically aligned MoS 2 flakes were grown on indium tin oxide (ITO) and ITO/ZnO substrates using metalorganic chemical vapor deposition. The thickness of MoS 2 flakes was manipulated at the few-layer level (5–10), which is desirable for energy-storage and energy-conversion applications. For photoelectrochemical (PEC) cells, a few-layer flake photoelectrode yielded a considerably higher photocurrent density (930 μA/cm 2 at 0.2 V) than a MoS 2 thin-film photoelectrode (360 μA/cm 2 at 0.2 V) due to the former's high density of active sites, slow intraband relaxation rate from excitonic states, and low defect density. Furthermore, the heterostructure of ZnO/MoS 2 flakes exhibited a remarkably high photocurrent density of 1.6 mA/cm 2 at 0.2 V and a long-term stability under the PEC operating conditions because of its enhanced photogenerated carrier separation and transfer. Thus, such a heterostructure is promising as an efficient, nontoxic, inexpensive, and earth-abundant PEC electrode.