Above 15% Efficient Directly Sputtered CIGS Solar Cells Enabled by a Modified Back-Contact Interface

作者：Wanlei Dai, Zeran Gao, Jianjun Li, Shumin Qin, Ruobing Wang, Haoyu Xu, Xinzhan Wang, Chao Gao, Xiaoyun Teng, Yu Zhang, Xiaojing Hao, Yinglong Wang, Wei Yu · 发表于：ACS Applied Materials & Interfaces · 年份：2021 · DOI：10.1021/acsami.1c11493 · 被引用次数：21 · 研究领域：Chalcogenide Semiconductor Thin Films、Quantum Dots Synthesis And Properties、Semiconductor materials and interfaces

The Schottky back-contact barrier at the Mo/Cu(In,Ga)Se 2 (CIGS) interface is one of the critical issues that restrict the photovoltaic performance of CIGS solar cells. The formation of a MoSe 2 intermediate layer can effectively reduce this back-contact barrier leading to efficient hole transport. However, the selenium-free atmosphere is unfavorable for the formation of the desired MoSe 2 intermediate layer if the CIGS films are prepared by the commonly used direct sputtering process. In this work, high-efficiency CIGS solar cells with a MoSe 2 intermediate layer were fabricated by the direct sputtering process without a selenium atmosphere. This is enabled by an intermediate CIGS layer deposited on the Mo substrate at room temperature before being ramped to a high temperature (600 °C). The room-temperature-deposited amorphous CIGS intermediate layer is Se rich, which reacts with the Mo substrate and forms very thin MoSe 2 at the interface during the high-temperature process. The formed MoSe 2 decreased the CIGS/Mo barrier height for better hole transport. Consequently, the CIGS solar cell with an 80 nm intermediate layer achieved a power conversion efficiency of up to 15.8%, which is a benchmark efficiency for the direct sputtering process without Se supply. This work provides the industry a new approach for commercialization of directly sputtered CIGS solar cells.