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Minimizing Interfacial Recombination in 1.8 eV Triple‐Halide Perovskites for 27.5% Efficient All‐Perovskite Tandems
Yang, Fengjiu; Tockhorn, Philipp; Musiienko, Artem; Lang, Felix; Menzel, Dorothee; Macqueen, Rowan; Köhnen, Eike; Xu, Ke; Mariotti, Silvia; Mantione, Daniele; Merten, Lena; Hinderhofer, Alexander; Li, Bor; Wargulski, Dan R.; Harvey, Steven P.; Zhang, Jiahuan; Scheler, Florian; Berwig, Sebastian; Roß, Marcel; Thiesbrummel, Jarla; Al‐Ashouri, Amran; Brinkmann, Kai O.; Riedl, Thomas; Schreiber, Frank; Abou‐Ras, Daniel; Snaith, Henry; Neher, Dieter; Korte, Lars; Stolterfoht, Martin; Albrecht, Steve
All-perovskite tandem solar cells show great potential to enable the highest performance at reasonable costs for a viable market entry in the near future. In particular, wide-bandgap (WBG) perovskites with higher open-circuit voltage (VOC) are essential to further improve the tandem solar cells’ performance. Here, a new 1.8 eV bandgap triple-halide perovskite composition in conjunction with a piperazinium iodide (PI) surface treatment is developed. With structural analysis, it is found that the PI modifies the surface through a reduction of excess lead iodide in the perovskite and additionally penetrates the bulk. Constant light-induced magneto-transport measurements are applied to separately resolve charge carrier properties of electrons and holes. These measurements reveal a reduced deep trap state density, and improved steady-state carrier lifetime (factor 2.6) and diffusion lengths (factor 1.6). As a result, WBG PSCs achieve 1.36 V VOC, reaching 90% of the radiative limit. Combined with a 1.26 eV narrow bandgap (NBG) perovskite with a rubidium iodide additive, this enables a tandem cell with a certified scan efficiency of 27.5%.
