Xie Yueping, Tian Tian, Mao Chengling, Wang Zhenyun, Shi Jingjia, Yang Li, Wang Cencen
School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418, China.
Shanghai Toplite Technology Company Limited, Shanghai 201712, China.
Nanomaterials (Basel). 2023 Feb 2;13(3):599. doi: 10.3390/nano13030599.
White light emitting diodes (WLEDs) are widely used due to their advantages of high efficiency, low electricity consumption, long service life, quick response time, environmental protection, and so on. The addition of red phosphor is beneficial to further improve the quality of WLEDs. The search for novel red phosphors has focused mainly on Eu ion- and Mn ion-doped compounds. Both of them have emissions in the red region, absorption in blue region, and similar quantum yields. Eu-doped phosphors possess a rather broad-band emission with a tail in the deep red spectral range, where the sensitivity of the human eye is significantly reduced, resulting in a decrease in luminous efficacy of WLEDs. Mn ions provide a narrow emission band ~670 nm in oxide hosts, which is still almost unrecognizable to the human eye. Mn-doped fluoride phosphors have become one of the research hotspots in recent years due to their excellent fluorescent properties, thermal stability, and low cost. They possess broad absorption in the blue region, and a series of narrow red emission bands at around 630 nm, which are suitable to serve as red emitting components of WLEDs. However, the problem of easy hydrolysis in humid environments limits their application. Recent studies have shown that constructing a core-shell structure can effectively improve the water resistance of Mn-doped fluorides. This paper outlines the research progress of Mn-doped fluoride AMF (A = Li, Na, K, Cs, or Rb; M = Si, Ti, Ge or Sn), which has been based on the core-shell structure in recent years. From the viewpoint of the core-shell structure, this paper mainly emphasizes the shell layer classification, synthesis methods, luminescent mechanism, the effect on luminescent properties, and water resistance, and it also gives some applications in terms of WLEDs. Moreover, it proposes challenges and developments in the future.
白光发光二极管（WLED）因其具有高效率、低功耗、长使用寿命、快速响应时间、环保等优点而被广泛应用。添加红色荧光粉有利于进一步提高WLED的质量。寻找新型红色荧光粉主要集中在Eu离子和Mn离子掺杂的化合物上。它们在红色区域都有发射，在蓝色区域有吸收，并且量子产率相似。Eu掺杂的荧光粉具有相当宽的发射带，在深红色光谱范围内有一个尾巴，而人眼在该区域的灵敏度显著降低，导致WLED的发光效率下降。Mn离子在氧化物基质中提供一个约670 nm的窄发射带，人眼几乎仍无法识别。Mn掺杂的氟化物荧光粉由于其优异的荧光性能、热稳定性和低成本，近年来已成为研究热点之一。它们在蓝色区域有宽吸收，在630 nm左右有一系列窄的红色发射带，适合用作WLED的红色发光组件。然而，在潮湿环境中容易水解的问题限制了它们的应用。最近的研究表明，构建核壳结构可以有效提高Mn掺杂氟化物的耐水性。本文概述了近年来基于核壳结构的Mn掺杂氟化物AMF（A = Li、Na、K、Cs或Rb；M = Si、Ti、Ge或Sn）的研究进展。从核壳结构的角度出发，本文主要强调壳层分类、合成方法、发光机理、对发光性能的影响以及耐水性，并给出了在WLED方面的一些应用。此外，还提出了未来面临的挑战和发展方向。
