Dai Wanlei, Gao Zeran, Li Jianjun, Qin Shumin, Wang Ruobing, Xu Haoyu, Wang Xinzhan, Gao Chao, Teng Xiaoyun, Zhang Yu, Hao Xiaojing, Wang Yinglong, Yu Wei
Hebei Key Laboratory of Optic-electronic Information and Materials, National-Local Joint Engineering Laboratory of New Energy Photoelectric Devices, College of Physics Science and Technology, Hebei University, Baoding 071002, China.
School of Photovoltaics and Renewable Energy Engineering, University of New South Wales, Sydney 2052, Australia.
ACS Appl Mater Interfaces. 2021 Oct 20;13(41):49414-49422. doi: 10.1021/acsami.1c11493. Epub 2021 Oct 7.
The Schottky back-contact barrier at the Mo/Cu(In,Ga)Se (CIGS) interface is one of the critical issues that restrict the photovoltaic performance of CIGS solar cells. The formation of a MoSe 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 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 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 at the interface during the high-temperature process. The formed MoSe 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.
Mo/Cu(In,Ga)Se（CIGS）界面处的肖特基背接触势垒是限制CIGS太阳能电池光伏性能的关键问题之一。MoSe中间层的形成可以有效降低这种背接触势垒，从而实现高效的空穴传输。然而，如果通过常用的直接溅射工艺制备CIGS薄膜，无硒气氛不利于形成所需的MoSe中间层。在这项工作中，通过无硒气氛的直接溅射工艺制备了具有MoSe中间层的高效CIGS太阳能电池。这是通过在室温下在Mo衬底上沉积中间CIGS层，然后再升温至高温（600°C）来实现的。室温沉积的非晶CIGS中间层富含Se，在高温过程中它与Mo衬底反应并在界面处形成非常薄的MoSe。形成的MoSe降低了CIGS/Mo势垒高度，以实现更好的空穴传输。因此，具有80nm中间层的CIGS太阳能电池实现了高达15.8%的功率转换效率，这是无Se供应的直接溅射工艺的基准效率。这项工作为直接溅射CIGS太阳能电池的商业化提供了一种新的行业方法。
