兰州大学王育华团队报道了无铅卤化物双钙钛矿单晶的高效宽带近红外发光。相关研究成果发表在2022年6月21日出版的《德国应用化学》。
超宽带近红外（NIR）发光材料是近红外发光器件（LED）中最重要的组成部分，对其在食品检测、医疗和生物传感应用中的性能至关重要。现阶段的一个主要挑战是设计新的近红外发光材料来取代传统的Cr3+掺杂系统。
该文报道了一种全无机卤化铋钙钛矿Cs2AgBiCl6单晶，通过引入钠离子实现了高效的宽带近红外发光。实验和密度泛函理论（DFT）计算表明，近红外发光源于自陷激子（STE）发射，可以通过减弱电子与声子之间的强耦合来增强。Cs2Ag0.05Na0.95BiCl6单晶具有51%的高光致发光量子效率（PLQY）、270 nm的半高宽（FWHM）和优异的稳定性，是其作为近红外发光材料的重要优势。基于单晶的近红外LED显示了其在近红外光谱检测和夜视方面的潜在应用。
该项工作表明，卤化铋钙钛矿是一种很有前景的宽带近红外发光材料，为发光金属卤化物提供了新的应用方向。
附：英文原文
Title: Efficient Broadband Near-Infrared Emission from Lead-Free Halide Double Perovskite Single Crystal
Author: Gangyi Zhang, Deyin Wang, Bibo Lou, Chong-Geng Ma, Andries Meijerink, YuHua Wang
Issue&Volume: 2022-06-21
Abstract: Ultra-broadband near-infrared (NIR) luminescent materials are the most important component of NIR light-emitting devices (LED) and are crucial for their performance in food detection, medical and bio-sensing applications. A major challenge at this stage is to design novel NIR luminescent materials to replace the traditional Cr3+-doped systems. This work reports an all-inorganic bismuth halide perovskite Cs2AgBiCl6 single crystal that achieves efficient broadband NIR emission by introducing Na ions. Experiments and density functional theory (DFT) calculations show that the NIR emission originates from self-trapped exciton (STE) emission, which can be enhanced by weakening the strong coupling between electrons and phonons. The high photoluminescence quantum efficiency (PLQY) of 51%, the extensive full width at half maximum (FWHM) of 270 nm and the outstanding stability provide important advantages of Cs2Ag0.05Na0.95BiCl6 single crystal as a NIR luminescent material. The single crystal based NIR LED demonstrated its potential applications in NIR spectral detection as well as night vision. This work demonstrates that the bismuth halide perovskites are promising candidates for broadband NIR luminescent materials and provides new application directions for luminescent metal halides.
DOI: 10.1002/anie.202207454
Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202207454
