Achieving 32% Efficiency in Perovskite/Silicon Tandem Solar Cells with Bidentate‐Anchored Superwetting Self‐Assembled Molecular Layers

Abstract The inhomogeneity of hole‐selective self‐assembled molecular layers (SAMLs) often arises from the insufficient bonding between anchors and metal oxide, particularly on textured silicon surfaces when fabricating monolithic perovskite/silicon tandem solar cells (P/S‐TSCs) and the hydrophobic carbazole complicates the fabrication of high‐quality perovskite films. To address this, we developed a novel bidentate‐anchored superwetting aromatic SAM based on an upside‐down carbazole core as a hole‐selective layer (HSL), denoted as ((9H‐carbazole‐3,6‐diyl)bis(4,1‐phenylene))bis(phosphonic acid) (2PhPA‐CzH). The bisphosphonate‐anchored exhibited enhanced adsorption capabilities and efficient hole extraction/transport, and the reversely substituted carbazole ring contributed a friendly super wetting underlayer that enabled high‐quality perovskite films with minimized energetic mismatches, which 2PhPA‐CzH played a pivotal role in dual interfacial energy regulation. Through these advancements, the optimized wide‐bandgap (1.68 eV) PSCs demonstrated an improved PCE of 22.83% and excellent stability with T90 exceeding 1000 h under damp‐heat conditions (ISOS‐D‐3, 85% RH, 85 °C), representing one of the best performances for SAMs as HSL‐based PSCs. Notably, 2PhPA‐CzH‐functionalized recombination layers extended to submicron‐pyramid texture SHJ to fabricate P/S‐TSCs, achieving an impressive efficiency of 32.19% at an active area of 1 cm2 (certified 31.54%) while maintaining excellent photostability. This work offers guidance for designing multidentate‐anchored SAMs to realize record PCE and excellent stability in P/S‐TSCs.