Synergistically Stabilizing Hole Transport Layer and Dual Interface Enables High-Performance Perovskite Solar Cells

Abstract

The migration and diffusion of Li+ and halide ions, as well as the volatilization of 4-tert butylpyridine (tBP), seriously restrain the long-term operational stability of n-i-p perovskite solar cells (PSCs). Herein, we employ l-glutamic acid dibenzyl ester 4-toluenesulfonate (GADET) to simultaneously modulate the hole transport layer (HTL) and buried interface, which stabilizes the HTL and minimizes interfacial energy loss by immobilizing Li+, tBP, and halide ions and passivating dual interface defects. After forming Spiro-OMeTAD•+TFSI–, GADET impedes the Li+ ion diffusion through the ionic bond interaction of P-methylbenzenesulfonate anion and Li+, while the formation of the hydrogen bond of −NH3+ with tBP can suppress the volatilization of tBP. Moreover, the halide ion migration and interfacial trap-induced nonradiative recombination are inhibited via passivating undercoordinated Pb and halide vacancy defects based on multiple chemical bonds. The synergistically modified devices achieve a champion efficiency of 25.06% (certified PCE of 24.08%). Meanwhile, the stability of PSCs was significantly improved.