An atomic gradient passivation layer, (Ta,Mo)x(O,S)y, is designed to improve the charge transportation and photoelectrochemical activity of CuInS2-based photoelectrodes. We found that Mo spontaneously diffused to the a-TaOx layer during e-beam evaporation. This result indicates that the gradient profile of MoOx/TaOx is formed in the sublayer of (Ta,Mo)x(O,S)y. To understand the atomic-gradation effects of the (Ta,Mo)x(O,S)y passive layer, the composition and (photo)electrochemical properties have been characterized in detail. When this atomic gradient-passive layer is applied to CuInS2-based photocathodes, promising photocurrent and onset potential are seen without using Pt cocatalysts. This is one of the highest activities among reported CuInS2 photocathodes, which are not combined with noble metal cocatalysts. Excellent photoelectrochemical activity of the photoelectrode can be mainly achieved by (1) the electron transient time improved due to the conductive Mo-incorporated TaOx layer and (2) the boosted electrocatalytic activity by Mox(O,S)y formation.
Bibliographical noteFunding Information:
This study was supported by the institutional program of the Korea Institute of Science and Technology (no. KIST-2E31241) and the C1 Gas Refinery Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (no. 2015M3D3A1A01064899). This research was also supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (no. 2020R1I1A1A01073326).
- atomic gradation
- passivation layer
- photoelectrochemical cell
- tantalum oxide
ASJC Scopus subject areas
- Materials Science(all)