Microenvironment Created by SnSe2 Vapor and Pre‐Selenization to Stabilize the Surface and Back Contact in Kesterite Solar Cells. Issue 47 (30th September 2022)

• Record Type: Journal Article
• Authors: Guo, Jiajia; Mao, Yang; Ao, Jianping; Han, Yanchen; Cao, Chun; Liu, Fangfang; Bi, Jinlian; Wang, Shenghao; Zhang, Yi
• Is Part Of: Small. Volume 18:Issue 47(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-09-30
• Subjects: Cu 2ZnSn(S, Se) 4 (CZTSSe) solar cells -- Mo(S;Se) 2 -- selenization process -- Sn content -- SnSe 2 vapor; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.202203354
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract: The ambient air‐processed preparation of kesterite Cu2 ZnSn(S, Se)4 (CZTSSe) thin film is highly promising for the fabrication of low‐cost and eco‐friendly solar cells. However, the Sn volatilization loss and formation of a thick Mo(S, Se)2 interfacial layer during the traditional selenization process pose challenges for fabricating high‐efficiency CZTSSe solar cells. Here, CZTS precursors prepared by a sol‐gel process in ambient air are selenized and assisted with SnSe2 vapor via one‐ and two‐step selenization to prepare a CZTSSe absorber on a Mo film and, subsequently, solar cells. For one‐step selenization, the thickness of the fine grain and Mo(S, Se)2 layers near the back contact can be significantly reduced with increasing SnSe2 vapor partial pressure in the mixed selenization atmosphere, while the device efficiency is only 7.97% due to the severe interface recombination. For two‐step selenization, the desired morphology and stoichiometry of the absorber can be achieved through the assistance of Sn‐poor precursors selenized with high SnSe2 vapor partial pressure to regulate the Sn content in CZTSSe, yielding the highest efficiency of 10.85%. This study improves the understanding of the key role of the microenvironment during film growth towards the production of high‐efficiency thin film solar cells and other photoelectronic devices. Abstract : The microenvironment created by the SnSe2 vapor and pre‐selenization process modulates the Sn volatilization loss and Mo(S, Se)2 interfacial layer formation in Cu2 ZnSn(S, Se)4 solar cells. Sufficient element interdiffusion produced by the pre‐selenization process dramatically enhances the effect of SnSe2 vapor on the increments in kesterite device performance.