Cui Guonan, Yang Yanchun, Bai Lulu, Wang Rui, Gong Zhihui, Cao Yongjun, Li Shuyu, Lv Xiaogong, Zhu Chengjun
Inner Mongolia Autonomous Region Engineering Research Center for Rare Earth Functions and New Energy Storage Materials, Inner Mongolia Normal University, 81 Zhaowuda Road, Hohhot, Inner Mongolia, 010022, China.
School of Physics and Electronic Information, Inner Mongolia Key Laboratory for Physics and Chemistry of Functional Materials, Inner Mongolia Normal University, 81 Zhaowuda Road, Hohhot, Inner Mongolia, 010022, China.
Small. 2024 Nov;20(47):e2405382. doi: 10.1002/smll.202405382. Epub 2024 Aug 21.
A suitable interlayer between the Mo back electrode and kesterite absorber layer has been proven to have a positive effect on limiting the bulk defects of the absorber by the constitute diffusion. Here, a thin BiS layer is used as the back-interface intermediate layer for the first time, this innovative approach allows for simultaneous modification of the back contact and reduction of bulk defects, resulting in improving the power conversion efficiency of the kesterite device from 9.66% to 11.8%. The evaporated BiO thin films turn into the BiS interlayers after sintering the CuZnSnS precursor thin films. The BiS interlayer can inhibit the decomposition reaction of back contact and suppress the formation of the secondary phases. It can also optimize the Fermi level offset and promote the separation of the photoinduced carriers, resulting from its characteristic of high work function. Besides, a small part of the Bi element can diffuse into CuZnSn(S, Se) film and induce the crystal growth and restrain Zn-related defects, which is attributed to forming the low melting-point liquid BiSe phase during the high-temperature selenization process. The conclusions highlight the bifunction of the thin BiS intermediate layer, which can provide a new approach to improve the photoelectric conversion efficiency of kesterite solar cells.
已证明，在钼背电极和锌黄锡矿吸收层之间设置合适的中间层，通过构成扩散对限制吸收层的体缺陷具有积极作用。在此，首次使用薄的BiS层作为背界面中间层，这种创新方法能够同时改善背接触并减少体缺陷，从而将锌黄锡矿器件的功率转换效率从9.66%提高到11.8%。在烧结CuZnSnS前驱体薄膜后，蒸发的BiO薄膜转变为BiS中间层。BiS中间层可以抑制背接触的分解反应并抑制第二相的形成。由于其高功函数特性，它还可以优化费米能级偏移并促进光生载流子的分离。此外，一小部分Bi元素可以扩散到CuZnSn(S, Se)薄膜中，诱导晶体生长并抑制与Zn相关的缺陷，这归因于在高温硒化过程中形成了低熔点液体BiSe相。这些结论突出了薄BiS中间层的双重功能，可为提高锌黄锡矿太阳能电池的光电转换效率提供一种新方法。
