Heterointerface Energetics Regulation Strategy Enabled Efficient Perovskite Solar Cells

Abstract In the domain of perovskite photovoltaics, the heterointerfaces are subject to substantial trap‐assisted non‐radiative recombination, predominantly attributed to the energy offset, interface defects, and the roughness of the contact. This phenomenon at the heterointerfaces, where carrier non‐radiative recombination and energy dissipation occur due to defects and suboptimal energy level alignment, can be principally held accountable for the V oc losses. Herein, a heterointerface energetics regulation (HER) strategy is proposed by introducing potassium trifluoroacetate (KTFA) in the perovskite precursor solution to eliminate the trap defects and optimize surface potential and Fermi level. It is first demonstrated that non‐doping K + but precipitating at the upper and buried perovskite will improve energy‐level alignment for charge extraction dynamics. In addition, the TFA − exhibits strong electrostatic force with undercoordinated Pb 2+ in the buried contact of perovskite and Sn 4+ in the SnO 2 electron transporting layer. Based on the vacuum flash evaporation green treatment without anti‐solvent, the Rb 0.02 (Cs 0.05 FA 0.95 ) 0.98 PbI 0.91 Br 0.03 Cl 0.06 and Cs 0.05 FA 0.95 PbI 3 based device can achieve maximum efficiency of 23.36% and 24.48%, respectively. Further, the modified devices exhibit 92% initial efficiency output after 1200 h of aging. HER strategy for addressing interface defects and bandgap alignment are poised to advance both the performance and stability of perovskite solar cells.