Modulating Adsorption Configurations of Hybrid Self‐assembled Molecules Enables High‐performance Inverted Perovskite Solar Cells

Abstract

Abstract Self‐assembled molecules (SAMs) as hole‐selective layers have achieved tremendous success in perovskite solar cells. However, the effective modulation of the adsorption configuration of hybrid SAMs on indium tin oxide (ITO) substrates remains a challenge, which essentially influences the SAM's orientation and homogeneity. Herein, the adsorption configuration of [4‐(3,6‐diphenyl‐9 H ‐carbazol‐9‐yl)butyl]phosphonic acid (Ph‐4PACz) on the ITO surface is modulated with co‐assembled molecules 2,3,5,6‐tetrafluoroterephthalic acid (BCA) or 2,3,5,6‐tetrafluoro‐4‐sulfanylbenzoic acid (BSCA). Specifically, planar BCA molecules anchored via bi‐carboxylic groups stabilize Ph‐4PACz in a tilted configuration, forming an angle of approximately 54.03° relative to the ITO surface, whereas tilted BSCA molecules anchored via mono‐carboxylic groups induce Ph‐4PACz to adopt an almost perpendicular orientation relative to the ITO surface. Upon BSCA introduction, the Ph‐4PACz film becomes more uniform with better energy level alignment, which further results in the enhanced homogeneity of the buried surface of perovskite films with enhanced charge transport and reduced interfacial non‐radiative recombination losses. Consequently, the resultant BSCA‐based devices achieve a high efficiency of 26.72% (certified 26.75%) for devices with the active area of 0.0717 cm 2 and 25.21% for 1 cm 2 , respectively, maintaining over 90% of their initial efficiencies after 1,500 h operational tracking under illumination or 1000 h at 85 °C heating.