Investigation of the Electric Structures of Heterointerfaces in Pt- and In₂S₃-Modified CuInS₂ Photocathodes Used for Sunlight-Induced Hydrogen Evolution

Gunawan; Wilman Septina; Takashi Harada; Yoshitaro Nose; Shigeru Ikeda

doi:10.1021/acsami.5b04634

Investigation of the Electric Structures of Heterointerfaces in Pt- and In₂S₃-Modified CuInS₂ Photocathodes Used for Sunlight-Induced Hydrogen Evolution

ACS Appl Mater Interfaces. 2015 Jul 29;7(29):16086-92. doi: 10.1021/acsami.5b04634. Epub 2015 Jul 14.

Authors

Gunawan^{1

2}, Wilman Septina¹, Takashi Harada¹, Yoshitaro Nose³, Shigeru Ikeda¹

Affiliations

¹ †Research Center for Solar Energy Chemistry, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.
² ‡Chemistry Department, Faculty of Science and Mathematics, Diponegoro University, Semarang, Indonesia.
³ §Department of Materials Science and Engineering, Kyoto University, Yoshida-Honmachi, Sakyo-ku, 606-8501 Kyoto, Japan.

PMID: 26172945
DOI: 10.1021/acsami.5b04634

Abstract

Copper indium disulfide (CuInS2) modified with an In2S3 layer and a Pt catalyst showed a more efficient photoelectrochemical (PEC) property for hydrogen evolution from a nearly neutral (pH 6) 0.2 M NaH2PO4 solution under simulated sunlight illumination (AM 1.5G) than that of a CuInS2 electrode modified with a CdS layer and a Pt catalyst. Analysis of the PEC properties of In2S3-modified CuInS2 (In2S3/CuInS2) and CdS-modified CuInS2 (CdS/CuInS2) in solutions containing an electron scavenger (Eu(3+)) showed identical enhancement of the PEC properties of In2S3/CuInS2 when compared to those of CdS/CuInS2, indicating the formation of a favorable heterointerface in In2S3/CuInS2 for efficient charge separation. Spectroscopic evaluation of conduction band offsets revealed that In2S3/CuInS2 had a notch-type conduction band offset, whereas a cliff-type offset was formed in CdS/CuInS2: these results also revealed a better interface electric structure of In2S3/CuInS2 than that of CdS/CuInS2.

Keywords: X-ray photoelectron spectroscopy; copper indium disulfide; heterointerface; indium disulfide; photocathodes.

Publication types

Research Support, Non-U.S. Gov't