Wei Yufan, Huang Qianxing, Yu Shijie, Shao Qiyue, Jiang Jianqing
School of Materials Science and Engineering, Jiangsu Key Laboratory for Advanced Metallic Materials, Southeast University, Nanjing 211189, P. R. China.
School of Mechanical and Electronic Engineering, Nanjing Forestry University, Nanjing 210037, P. R. China.
ACS Appl Mater Interfaces. 2024 Oct 16;16(41):55792-55801. doi: 10.1021/acsami.4c12727. Epub 2024 Oct 8.
The KSiF:Mn (KSFM) phosphor featuring efficient ultranarrow red emissions is an outstanding candidate for white light-emitting diode (WLED) applications. However, poor moisture resistance seriously affects its application performance. In this study, a two-step surface reconstruction strategy is proposed to dramatically enhance the moisture resistance of commercially available KSFM phosphors, involving treatment with HNbF and subsequent hydrothermal treatment. The modified KSFM phosphor exhibits a high internal quantum efficiency (IQE) of 98.9% after the two-step surface treatment. Meanwhile, nearly 100% of the initial emission intensity is retained for the modified KSFM phosphor even after aging in high temperature (85 °C) and high relative humidity (85% RH) environments for 6 days, in sharp contrast to only 18.6% retention for the original KSFM phosphor. The relative emission intensity of the modified KSFM remains at 98.9% even after being immersed in water for 6 h. Additionally, the phosphor-converted LED fabricated with the modified KSFM phosphor demonstrated excellent long-term stability, retaining up to 97.9% of initial luminous efficacy after aging under 85 °C and 85% RH conditions for 500 h. The moisture-resistance mechanism is elucidated on the basis of spectroscopic analysis as well as structural and compositional characterization of the phosphor surface layer, which can be attributed to the formation of a robust Mn-rare shell with high crystalline quality following this two-step surface treatment. The findings contribute to the performance improvements of KSFM phosphors for industrial applications.
具有高效超窄红色发射的KSiF:Mn（KSFM）荧光粉是白光发光二极管（WLED）应用的杰出候选材料。然而，其耐湿性较差严重影响了其应用性能。在本研究中，提出了一种两步表面重构策略，以显著提高市售KSFM荧光粉的耐湿性，该策略包括用HNbF处理和随后的水热处理。经过两步表面处理后，改性KSFM荧光粉表现出98.9%的高内量子效率（IQE）。同时，即使在高温（85°C）和高相对湿度（85%RH）环境中老化6天后，改性KSFM荧光粉仍保留了近100%的初始发射强度，而原始KSFM荧光粉仅保留18.6%。改性KSFM荧光粉即使在水中浸泡6小时后，其相对发射强度仍保持在98.9%。此外，用改性KSFM荧光粉制备的荧光粉转换型LED表现出优异的长期稳定性，在85°C和85%RH条件下老化500小时后，仍保留高达97.9%的初始发光效率。基于光谱分析以及荧光粉表面层的结构和成分表征，阐明了其耐湿机理，这可归因于经过两步表面处理后形成了具有高结晶质量的坚固Mn-稀土壳层。这些发现有助于提高KSFM荧光粉在工业应用中的性能。
