Efficient Red-Emissive Circularly Polarized Electroluminescence Enabled by Quasi-2D Perovskite with Chiral Spacer Cation

Abstract

Perovskites are promising environmentally sustainable materials for circularly polarized electroluminescence (CPEL). While another chiral nonemissive layer is required for the developed perovskite-based CPEL, we report herein a highly efficient circularly polarized electroluminescence based on a single layer of quasi-2D perovskite with achiral phenethylammonium iodide (PEAI) and chiral <i>S</i>/<i>R</i>-1-(1-naphthyl)ethylammonium iodide (S/R-NEAI) as dual spacer cations. The quasi-2D perovskite was further passivated by carbazole-functionalized phosphonium. The as-fabricated film exhibits not only a circular dichroism (CD) signal but also prominent circularly polarized luminescence (CPL) activity with a maximum photoluminescence dissymmetry factor (<i>g</i>_lum) of ∼2.1 × 10^-3. More importantly, a highly efficient, spin-polarized light-emitting diode (LED) was fabricated based on the <i>in situ</i> passivated quasi-2D perovskite with a peak external quantum efficiency of 3.7% and a maximum electroluminescence dissymmetry factor (<i>g</i>_EL) of ∼4.0 × 10^-3.