Gao Qing, Zhang Yongheng, Ao Jianping, Bi Jinlian, Yao Liyong, Guo Jiajia, Sun Guozhong, Liu Wei, Liu Fangfang, Zhang Yi, Li Wei
Key Laboratory of Photo-electronic Thin Film Devices and Technology of Tianjin, Engineering Research Center of Thin Film Photo-electronic Technology, Ministry of Education, Institute of Photo-electronic Thin Film Devices and Technology of Nankai University, Tianjin 300350, P.R. China.
Tianjin Key Laboratory of Film Electronic and Communication Devices School of Electrical and Electronic Engineering, Tianjin University of Technology, Tianjin 300384, China.
ACS Appl Mater Interfaces. 2021 Jun 2;13(21):25451-25460. doi: 10.1021/acsami.1c00270. Epub 2021 May 19.
The surface Ga content for a CIGSe absorber was closely related to variation in the open-circuit voltage (), while it was generally low on a CIGSe surface fabricated by two-step selenization. In this work, a solution-processed surface treatment based on spin-coating GaCl solution onto a CIGSe surface was applied to increase the Ga content on the surface. XPS, XRD, Raman spectroscopy, and band gap extraction based on the external quantum efficiency response demonstrated that GaCl post deposition treatment (GaCl-PDT) can be used to enhance the Ga content on the surface of a CIGSe absorber. Meanwhile, a solution-processed surface treatment with KSCN (KSCN-PDT) was employed to form a transmission barrier for holes by moving the valence band maximum downward and decreasing the interface recombination between the CdS and CIGSe layers. Admittance spectroscopy results revealed that deep defects were passivated by GaCl-PDT or KSCN-PDT. By applying the combination of GaCl-PDT and KSCN-PDT, a champion device was realized that exhibited an efficiency of 13.5% with an improved of 610 mV. Comparing the efficiency of the untreated CIGSe solar cells (11.7%), the CIGSe device efficiency with GaCl-PDT and KSCN-PDT exhibited 15% enhancement.
CIGSe吸收层的表面Ga含量与开路电压（）的变化密切相关，而在两步硒化制备的CIGSe表面上其含量通常较低。在本工作中，采用了一种基于旋涂GaCl溶液到CIGSe表面的溶液处理表面处理方法来提高表面的Ga含量。X射线光电子能谱（XPS）、X射线衍射（XRD）、拉曼光谱以及基于外量子效率响应的带隙提取结果表明，GaCl后沉积处理（GaCl-PDT）可用于提高CIGSe吸收层表面的Ga含量。同时，采用KSCN溶液处理表面（KSCN-PDT），通过使价带最大值下移并减少CdS和CIGSe层之间的界面复合来形成空穴传输势垒。导纳谱结果表明，GaCl-PDT或KSCN-PDT钝化了深缺陷。通过结合使用GaCl-PDT和KSCN-PDT，实现了一个冠军器件，其效率为13.5%，开路电压提高到610 mV。与未处理的CIGSe太阳能电池效率（11.7%）相比，采用GaCl-PDT和KSCN-PDT的CIGSe器件效率提高了15%。
