Li Yingfen, Jian Yue, Huang Fang, Zhou Nian, Chai Wanqiu, Hu Juguang, Zhao Jun, Su Zhenghua, Chen Shuo, Liang Guangxing
College of Materials and Energy Engineering, Guizhou Institute of Technology, Guiyang, 550003, China.
Shenzhen Key Laboratory of Advanced Thin Films and Applications, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, State Key Laboratory of Radio Frequency Heterogeneous Integration, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong, 518060, China.
Small. 2024 Aug;20(35):e2401330. doi: 10.1002/smll.202401330. Epub 2024 Apr 16.
CuZnSn (S,Se) (CZTSSe), a promising absorption material for thin-film solar cells, still falls short of reaching the balance limit efficiency due to the presence of various defects and high defect concentration in the thin film. During the high-temperature selenization process of CZTSSe, the diffusion of various elements and chemical reactions significantly influence defect formation. In this study, a NaOH-Se intermediate layer introduced at the back interface can optimize CuZnSnS (CZTS)precursor films and subsequently adjust the Se and alkali metal content to favor grain growth during selenization. Through this back interface engineering, issues such as non-uniform grain arrangement on the surface, voids in bulk regions, and poor contact at the back interface of absorber layers are effectively addressed. This method not only optimizes morphology but also suppresses deep-level defect formation, thereby promoting carrier transport at both interfaces and bulk regions of the absorber layer. Consequently, CZTSSe devices with a NaOH-Se intermediate layer improved fill factor, open-circuit voltage, and efficiency by 13.3%. This work initiates from precursor thin films via back interface engineering to fabricate high-quality absorber layers while advancing the understanding regarding the role played by intermediate layers at the back interface of kesterite solar cells.
铜锌锡（硫，硒）（CZTSSe）是一种很有前景的薄膜太阳能电池吸收材料，但由于薄膜中存在各种缺陷且缺陷浓度较高，其仍未达到平衡极限效率。在CZTSSe的高温硒化过程中，各种元素的扩散和化学反应对缺陷形成有显著影响。在本研究中，在背界面引入的NaOH-Se中间层可以优化铜锌锡硫化物（CZTS）前驱体薄膜，并随后调整硒和碱金属含量，以利于硒化过程中的晶粒生长。通过这种背界面工程，有效解决了诸如表面晶粒排列不均匀、体区域中的空隙以及吸收层背界面处接触不良等问题。该方法不仅优化了形貌，还抑制了深层缺陷的形成，从而促进了吸收层在两个界面和体区域的载流子传输。因此，具有NaOH-Se中间层的CZTSSe器件的填充因子、开路电压和效率提高了13.3%。这项工作从前驱体薄膜出发，通过背界面工程制备高质量的吸收层，同时加深了对中间层在硫锡铜矿太阳能电池背界面所起作用的理解。
