摘要
近红外荧光粉是实现高效荧光转换型LED(pc-LED)光源的关键材料,然而,开发具有较长发射波长、较宽发射带宽且光谱易于调节的近红外荧光粉仍然是重要挑战。本研究通过高温固相法合成了一系列Cr^(3+)掺杂的具有固溶性质的铝/硅莫来石(Al_(4+2z)Si_(2-2z)O_(10-z)∶Cr^(3+))荧光粉,揭示了Cr^(3+)在八面体[CrO_(6)]和四面体[CrO_(4)]格位的发光特性,并通过浓度调控实现了光谱位移与展宽。通过调节铝/硅的比例,可实现光谱的调控。进一步调节Cr^(3+)掺杂浓度,观察到八面体发光因激活离子间交换相互作用发生浓度猝灭,导致光谱随掺杂浓度增加显著红移(785→850 nm)。在405 nm激发下,优化后的1.6/1-mullite∶Cr^(3+)样品发射光谱涵盖了695~950 nm范围,其半高宽(FWHM)达到190 nm,该发射来源于Cr^(3+)在八面体中间晶体场(D_(q)/B=2.3)下的^(4)T_(2g)→^(4)A_(2)及^(2)Eg→^(4)A_(2g)跃迁,以及Cr^(3+)在四面体弱晶体场(D_(q)/B=1.02)中的^(4)T_(2g)→^(4)T_(1g)跃迁。此外,该荧光粉在423 K下仍保持63%的室温发光强度,其发光内量子产率和外量子产率分别达到53%和24%,表明该材料是一种有应用潜力的宽带近红外荧光粉。
Near-infrared(NIR)phosphors are critical materials for high-efficiency phosphor-converted LED(pc-LED)light sources.However,the development of NIR phosphors with long emission wavelengths,broad emission bandwidths,and tunable spectra remains a significant challenge.In this study,a series of Cr^(3+)-doped aluminum/silicon mullite(Al_(4+2z)Si_(2-2z)O_(10-z)∶Cr^(3+))phosphors with solid-solution properties were synthesized via a high-temperature solid-state reaction.The luminescence characteristics of Cr^(3+)in both octahedral[CrO_(6)]and tetrahedral[CrO_(4)]sites were systematically investigated.Spectral shift and broadening were achieved through concentration regulation.By adjusting the aluminum/silicon ratio,effective spectral tuning was realized.Further modulation of Cr^(3+)doping concentration revealed concentration quenching in octahedral-site emission due to exchange interactions between activators,resulting in a notable spectral red shift(785→850 nm)with increasing dopant concentration.Under 405 nm excitation,the optimized 1.6/1-mullite∶Cr^(3+)sample exhibited a broad emission spanning 695-950 nm,featuring a full width at half maximum(FWHM)of 190 nm.This emission originates from the ^(4)T_(2g)→4A_(2g) and ^(2)E_(g)→4A_(2g) transitions of Cr^(3+)in octahedral sites under an intermediate crystal field(D_(q)/B=2.30),as well as the ^(4)T_(2g)→^(4)T_(1g) transition in tetrahedral sites with a weaker crystal field(D_(q)/B=1.02).Additionally,the phosphor retained 63%of its room-temperature emission intensity at 423 K,with internal and external quantum yields reaching 53%and 24%,respectively.These results demonstrate the potential of this material as a high-performance broadband NIR phosphor for practical applications.
作者
常金昊
潘梓欣
梁思思
朱浩淼
CHANG Jinhao;PAN Zixin;LIANG Sisi;ZHU Haomiao(College of Chemistry and Materials Science,Fujian Normal University,Fuzhou 350007,China;Fujian College,University of Chinese Academy of Sciences,Fuzhou 350002,China;Xiamen Key Laboratory of Rare Earth Photoelectric Functional Materials,Xiamen Research Center of Rare Earth Materials,Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences,Xiamen 361021,China)
出处
《发光学报》
北大核心
2025年第8期1430-1441,共12页
Chinese Journal of Luminescence
基金
国家重点研发项目(2021YFB3500401)
福建省自然科学基金项目(2023J01214)。
