Lead-free halide double perovskites have gathered wide scientific interest since they are environmentally friendly and stable. However, compared to the lead perovskites, their optoelectronic properties are compromised. Herein we report a series of bulk lead-free mixed Bi-In halide double perovskites: Cs₂AgBi_1−xIn_xCl₆ (0<x<1). The Cs₂AgBi_0.125In_0.875Cl₆ breaks the parity-forbidden transition and retains direct band gap structure, having warm-white light emission, with photoluminescence quantum efficiency (PLQE) of 70.3%, much higher than the PLQE of reported lead perovskite materials. Its exciton self-trapping dynamics is investigated. Meanwhile, the Cs₂AgBi_0.125In_0.875Cl₆ nanocrystals and Cs₂AgBi_0.125In_0.875Cl₆ microcrystals can be synthesized by modified hot injection and rapid cooling crystallization, respectively. The size effect of Cs₂AgBi_0.125In_0.875Cl₆ is studied on the photoluminescence (PL) property. Additionally, the bulk material exhibits excellent stability on exposure to light, humidity and air for more than 3 months. It is a promising candidate as highly efficient warm white-light emitting material for road lighting.

无铅卤化物双钙钛矿具有环保和稳定的特性，因此引起了广泛的科学兴趣。然而，与铅钙钛矿相比，它们的光电性能受到损害。在这里，我们报告了一系列的大块无铅混合Bi-In卤化物双钙钛矿：Cs ₂ AgBi _{1- x} In _x Cl ₆（0 < x <1）。Cs ₂ AgBi _0.125 In _0.875 Cl ₆打破了奇偶禁止的跃迁，并保留了直接带隙结构，具有暖白光发射，其光致发光量子效率（PLQE）为70.3％，远高于已报道的钙钛矿铅材料的PLQE。研究了其激子自陷动力学。同时，在Cs ₂ AGBI _0.125在_0.875氯₆纳米晶体和Cs ₂ AGBI _0.125在_0.875氯₆微晶可以通过改性热注入和快速冷却结晶，分别合成。Cs ₂ AgBi _0.125 In _0.875 Cl ₆的尺寸效应研究了光致发光（PL）特性。另外，该散装材料在暴露于光，湿气和空气中超过3个月时表现出极好的稳定性。作为用于道路照明的高效暖白光发射材料，它是有前途的候选者。