[9p-P06-1~37] 12.5 Organic and hybrid solar cells

[9p-P06-14] Direct observation of charge transfer at the interface of Sn-Ge perovskite solar cells

〇(M2)Xubo Zhang¹, Liqi Liu¹, Yizhou Chen¹, Atsushi Sato¹, Kazuhiro Marumoto^1,2,3 (1.Dep. Mater. Sci., Univ. of Tsukuba, 2.OIQSST, Univ. of Tsukuba, 3.TREMS, Univ. of Tsukuba)

Keywords:

perovskite solar cells,Electron Spin Resonance

Sn-Ge perovskite solar cells are promising candidates for next-generation photovoltaics due to their low cost, flexibility, and eco-friendliness. However, the instability caused by the oxidation of Sn2+ and Ge2+ remains a challenge. In this study, we introduced a mixed solvent system using triethanolamine (TEA) and N-methylpyrrolidone (NMP) instead of conventional DMSO-based solvents to suppress oxidation. We fabricated solar cell devices with the structure ITO/PEDOT:PSS/MASn0.5Ge0.5I3/C60/BCP/Ag and conducted electron spin resonance (ESR) measurements under nitrogen atmosphere. The ESR results revealed a reduction in polaron concentration at the PEDOT:PSS layer after perovskite deposition, indicating hole transfer from the perovskite to PEDOT:PSS. This direct observation of interfacial charge transfer provides valuable insight into the internal mechanisms of Sn-Ge perovskite devices and supports further development of stable, lead-free solar cells.