Color-Stable Two-Dimensional Tin-Based Perovskite Light-Emitting Diodes: Passivation Effects of Diphenylphosphine Oxide Derivatives

摘要

The performance of tin (Sn)-based perovskite light-emitting diodes (PeLEDs)lags behind their lead analogs due to the challenges of Sn~（2+） oxidation, defectpassivation, and fast crystallization. Herein, the passivation effects of diphenylphosphineoxide (DPPO) derivatives on the fabrication of PEA_2SnI_4 filmsare investigated. The DPPO derivatives with hydroxyl group, or includingsubstituent group with the potential to form hydroxyl group, are unfavorablepassivators due to their positive effects in accelerating Sn~（2+） oxidation. Incomparison, amino-functionalized DPPO molecule is an effective additive toenhance the photoluminescence of PEA2SnI4 films due to the effective defectpassivation as well as crystallinity improvement. Based on the optimizedfilms, color-stable pure-red PeLEDs are demonstrated with a full width at halfmaximum of 23 nm at 630 nm, a maximum luminance of 451 cd m~(?2), a maximumexternal quantum efficiency of 3.51, and a half-lifetime of 13.7 minat 102 cd m?2. This work opens new prospects on the selection of effectivemolecular additives for Sn-based perovskites.