High carriers transmission efficiency ZnS/SnS 2 heterojunction channel toward excellent photoelectrochemical activity

• Published in: Journal of the American Ceramic Society Vol. 102; no. 5; pp. 2810 - 2819
• Main Authors: Zhang, Jun, Huang, Guozhou, Zeng, Jinghui, Shi, Yuxuan, Lin, Songjun, Chen, Xuan, Wang, Hongbo, Kong, Zhe, Xi, Junhua, Ji, Zhenguo
• Format: Journal Article
• Language: English
• Published: 01.05.2019
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/jace.16097

Abstract ZnS has been found superiority in photoelectrochemistry for the fast response of photo‐inducing and its high conductor band position (~0.8 eV) results in strong reduction ability for hydrogen production. However, the solar absorbance of ZnS is much low for the wide band gap (~3.2 eV) and the carriers’ migration efficiency also need to be improved. Here, nano‐ZnS were coupled with ultrathin SnS 2 nanosheets as heterojunction composites. This heterojunction composite demonstrated largely increase in specific surface area (from 4 to 12‐25 m 2 /g), obvious improvement of UV ‐vis absorbance and narrower band gap. Furthermore, the carriers’ migration efficiency of ZnS/SnS 2 heterojunction has been confirmed to be much higher by photocurrent response and electrochemical impedance spectroscopy. Due to the improvement in structure, compared with pristine ZnS, this ZnS/SnS 2 heterojunction exhibited vast enhancement in photoelectrochemical performance. The composite with best activity exhibited 12.8 times enhancement in photocurrent density. The conduction band and valence band of ZnS are both more negative than those of SnS 2 , the photo‐induced electrons at the conduction band of ZnS will transfer into the conduction band of SnS 2 while the photo‐induced holes at the valence band of SnS 2 will transfer into the valence band of ZnS. In this way, the photo‐produced carriers will flow into different semiconductors and the carriers’ migration efficiency is enhanced. The work improves a new structure to develop the heterojunction property for photoelectrochemical application.