Presentation Information
[9a-E201-2]Buried Interface Engineering Enables Efficient and Stable Pb-Sn Mixed Perovskite Solar Cells
〇(DC)Md Ataur Rahman1,2, Md. Emrul Kayesh1, Kiyoto Matsuishi2, Ashraful Islam1 (1.NIMS, 2.Univ. of Tsukuba)
Keywords:
Pb-Sn mixed perovskite
Due to ideal bandgap and excellent near-infrared light-harvesting capability, lead (Pb)-tin (Sn) mixed perovskite solar cells (LTMPSCs) have emerged as promising bottom subcells for all-perovskite tandem solar cells1,2. However, buried-interface defects and lattice instability under continuous illumination cause severe non-radiative recombination, accelerate ion migration, and limit both photovoltaic performance and operational stability3. Moreover, the commonly used hole-transport layer, poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS), possesses acidic and hygroscopic properties that deteriorate the interfacial environment, and the rapid crystallization of Sn-containing perovskites generates non-uniform films with high defect densities originating from the buried interface2. Therefore, simultaneous regulation of buried-interface chemistry and lattice stability is essential for achieving efficient and durable LTMPSCs. To address these issues, an interface-guided strategy is developed by inserting a thin molecular interlayer of 1-amino-8-naphthol-3,6-disulfonic acid monosodium (SANS) between PEDOT:PSS and the perovskite absorber (Figure 1a, b). The sulfonate (-SO3-), protonated amino (-NH3+), and hydroxyl (-OH) functional groups of SANS synergistically coordinate with undercoordinated Pb2+/Sn2+ ions, neutralize the acidity of PEDOT:PSS, and regulate nucleation and crystallization. Furthermore, the high dipole moment of SANS produces a strong interfacial molecular field that promotes lattice ordering and suppresses photo-induced ion migration and phase segregation. As a result, the optimized device exhibits a PCE of 23.93%, a high VOC of 0.90 V, and an FF of 82.8% (Figure 1c), along with robust operational stability.