Involving Hydroxyl-Rich d-Glucamine to Address Hole Extraction Interfacial Issues toward Efficient and Stable Tin-Based Perovskite Solar Cells

Two-dimensional (2D)/three-dimensional (3D) mixed tin (Sn)-based perovskites are a kind of excellent active layer in solar cells with significantly enhanced open-circuit voltage, stability, and power conversion efficiency (PCE). Unfortunately, low film coverage and poor morphology issues exist during the spin coating process of these 2D/3D perovskites, which further induce deterioration of device performance and stability. Herein, involving d-glucamine with hydroxyl and amino groups into the hole extraction layer poly(3,4-ethenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is testified to effectively overcome the PEDOT:PSS and 2D/3D mixed perovskite interfacial issues. The multihydroxyl and amino groups from d-glucamine can adequately anchor iodide ions (free I– or [SnI6]4–) of the PEA0.1(FA0.75MA0.25)0.9SnI3 perovskite via hydrogen bonds, which not only induces more nucleation sites to promote crystallinity along the preferential crystal orientations but also suppresses iodide migration and trap state density. All of these facilitate the formation of smooth and compact high-quality perovskite films with fewer traps and enhanced stability. Based on this strategy, an inverted perovskite solar cell (PSC) with a champion PCE of 9.61% and a lifetime of 750 h with 80% of the initial efficiency in N2 is finally achieved. This work demonstrates a valuable method for fabricating efficient and stable 2D/3D mixed Sn-based PSCs.