One-Dimensional Organic–Inorganic Hybrid Double Perovskites with Near-Unity Photoluminescence Quantum Yield and Advanced Multifunctional Applications

Lead-free halide double perovskites (DPs) have attracted extensive attention due to their excellent optoelectronic properties, but the synthesis of one-dimensional (1D) organic–inorganic hybrid halide DPs with high photoluminescence quantum yield (PLQY) is still challenging to date. Herein, we successfully prepared high-quality 1D hybrid (TMA)₂NaInCl₆ (TMA is tetramethylammonium) DPs by two synthetic routes and near-unity PLQY was achieved by incorporating Sb³⁺ ions into (TMA)₂NaInCl₆, which is much higher than that of 3D all-inorganic DPs. Temperature-dependent PL spectroscopic characterizations indicated that strong electron–phonon coupling existed in the excited state in doped system. Density functional theory calculations revealed that the incorporation of Sb³⁺ ions modulated the distribution of density of states and 24-fold enhancing in transition probability thereby significantly improved the PLQY. Our study presented new physical insights for in-depth understanding photophysical mechanisms and should be very important for regulating the optical performance of perovskite materials.