Te4+/Bi3+掺杂的Cs2SnCl6微米晶实现白光LED

WLED Achieved by Te4+/Bi3+ Doped Cs2SnCl6 Microcrystals

摘要: 金属钙钛矿卤化物因其优异的光学性能和易于溶液加工的特点而在下一代固态照明中受到广泛关注。尽管铅基钙钛矿具有可调谐的带隙、窄发射带和高载流子迁移率等优点，但其毒性大、稳定性差等缺点限制了其应用。在此，我们报道了Bi³⁺和Te⁴⁺掺杂的锡基钙钛矿Cs₂SnCl₆微米晶材料，Cs₂SnCl₆:Bi³⁺表现出由Bi³⁺的³P_0,1 → ¹S₀跃迁引起的450 nm的蓝光发射，Cs₂SnCl₆:Te⁴⁺表现出由Te⁴⁺的³P_0,1 → ¹S₀跃迁引起的570 nm的黄光发射。上述荧光材料的光致发光量子产率分别可达61.07%和63.73%，并且其在空气环境、热、水中都具有优异的稳定性。我们通过混合不同比例的Cs₂SnCl₆:Te⁴⁺和Cs₂SnCl₆:Bi³⁺微米晶可实现从暖白光到冷白光的调谐，其光输出色温(CCT)实现了从6237 K到7422 K的变化，最高显色指数(CRI)可达93。本工作表明过渡金属离子掺杂的无铅卤化物钙钛矿可作为高效荧光材料，实现高性能白光LED。

Abstract: Metal perovskite halides have received much attention in the next generation of solid-state lighting because of their excellent optical properties and easy solution processing. Although Pb-based perovskite has the advantages of a tunable band gap, narrow emission band, and high carrier mobility, its disadvantages such as high toxicity and poor stability limit its application. Here, we report that Bi³⁺ and Te⁴⁺ doped tin-based perovskite Cs₂SnCl₆ microcrystals are explored, and Cs₂SnCl₆:Bi³⁺ exhibits 450 nm blue emission originated from ³P_0,1 → ¹S₀ transition of Bi³⁺, while Cs₂SnCl₆:Te⁴⁺ exhibits a 570 nm yellow emission for the ³P_0,1 → ¹S₀ transition of Te⁴⁺. The photoluminescence quantum yields of the as explored perovskites reach 61.07% and 63.73%, respectively. Moreover, excellent stability of these perovskites in air, heat, and water is demonstrated. By regulating the proportions of Cs₂SnCl₆:Te⁴⁺ and Cs₂SnCl₆:Bi³⁺ microcrystals, white light emitting diodes (LEDs) with distinct color temperature tuning from warm white to cold white output could be achieved, and the corresponding color temperature (CCT) changes from 6237 K to 7422 K, with a maximum color rendering index (CRI) of 93. This work provides a reference for realizing high-performance white LED by transition metal ion-doped lead-free halide perovskite.