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An ITO-Free Kesterite Solar Cell.

Authors :: Ji Y
Chen W
Yan D
Bullock J
Xu Y
Su Z
Yang W
Laird JS
Zheng T
Wu N
Zha W
Luo Q
Ma CQ
Smith TA
Liu F
Mulvaney P
Source :: Small (Weinheim an der Bergstrasse, Germany) [Small] 2024 Feb; Vol. 20 (6), pp. e2307242. Date of Electronic Publication: 2023 Sep 28.
Publication Year :: 2024
Abstract: Photovoltaic thin film solar cells based on kesterite Cu <subscript>2</subscript> ZnSn(S, Se) <subscript>4</subscript> (CZTSSe) have reached 13.8% sunlight-to-electricity conversion efficiency. However, this efficiency is still far from the Shockley-Queisser radiative limit and is hindered by the significant deficit in open circuit voltage (V <subscript>OC</subscript> ). The presence of high-density interface states between the absorber layer and buffer or window layer leads to the recombination of photogenerated carriers, thereby reducing effective carrier collection. To tackle this issue, a new window structure ZnO/AgNW/ZnO/AgNW (ZAZA) comprising layers of ZnO and silver nanowires (AgNWs) is proposed. This structure offers a simple and low-damage processing method, resulting in improved optoelectronic properties and junction quality. The ZAZA-based devices exhibit enhanced V <subscript>OC</subscript> due to the higher built-in voltage (V <subscript>bi</subscript> ) and reduced interface recombination compared to the usual indium tin oxide (ITO) based structures. Additionally, improved carrier collection is demonstrated as a result of the shortened collection paths and the more uniform carrier lifetime distribution. These advances enable the fabrication of the first ITO-free CZTSSe solar cells with over 10% efficiency without an anti-reflective coating.<br /> (© 2023 The Authors. Small published by Wiley-VCH GmbH.)