Yutao Wang, Pengxu Chen, Fei Wang, Shuangbiao Xia, Yuhui Ji, Yunren Luo, Jianliang Wang, Zhenzhu Zhao, Junlin Du, Na Wang, Fanying Meng, Chen Yang, Hanlin Hu, Jian Yu, Jingjing Xu, Hongjun Cao, Hong Xiao, Sijie Wei, Kexin Yao, Jiakai Liu, Zhengxin Liu, Wenzhu Liu, Liping Zhang
The alignment of work function between transparent conducting oxides and charge transport layers is critical for the fill factor in perovskite/silicon tandem solar cells. Silvaco TCAD simulations show that a higher work function in tungsten-doped indium oxide (IWO) improves hole extraction in the perovskite subcell. In comparison, a lower work function enhances electron transport in the silicon subcell. To address this, a dual IWO interlayer with a graded work function is engineered via reactive plasma deposition by tuning the oxygen-to-argon flow rate ratio. This resolves interfacial mismatches and promotes carrier recombination. Furthermore, the optimized IWO surface facilitates improved anchoring with [4-(3,6-dimethoxy-9H-carbazol-9-yl)butyl]phosphonic acid (MeO-4PACz), thereby enhancing the quality of the perovskite layer. As a result, the optimized device achieved a power conversion efficiency (PCE) of 31.91%. This silicon-centric approach offers a scalable fabrication route for high-efficiency tandem solar cells.