高显色性白光LED用硅基氮(氧)化物荧光粉的合成技术及其配色封装调控机理研究

Taking the system constituted of LED chips, the preparation techniques of phosphors, surface treatment techniques and evaluating system for luminosity & chromaticity performance parameters as research objects, the regulation mechanism of spectra and color rendition matching for efficacy and color rendering of WLED was researched. In theory, based on the first principles calculation method of density functional theory (DFT) and semi-empirical method for materials，the law and relationship of the synthesis technology of (oxo)nitridosilicate phosphors and spectral characteristics of phosphors were modeled. And the model of optical transition in the excited states was established based on fluorescence spectra and Raman spectra, describing the various kinds of the electronic transition mechanism and the effect of fluorescence quenching existing in phosphors. Finally, the evaluation system of luminosity & chromaticity performance parameters and the color rendition matching database for high efficiency WLED was completed. Experimentally, the influence mechanism of the multi-step high temperature solid state method with tunable precursor and the dielectric film coating technology based on ALD technology on the spectrum properties of phosphors were analyzed. High quantum efficiency and spectra tuning (oxo)nitridosilicate phosphors matching the LED chips were prepared and the multi-level phosphor samples database was created. Based on the colorimetric principles and the optimal evaluation model for luminosity & chromaticity performance parameters, the color rendition matching schemes database of phosphor samples was constructed, matching blue LED, near ultraviolet LED. Finally, the high efficiency and high color rendering WLED was prepared with integrated packaging process.High efficiency and high color rendering WLED technology were realized by theoretical model, numerical calculation and experiment.

以LED芯片、荧光粉合成技术、表面处理技术及光色性能评价体系所构成的系统为研究对象，深入探究荧光粉光谱调控及其配色调控对WLED光效和显色性的作用机理。理论上，基于第一性原理计算与半经验方法，建立硅基氮（氧）化物荧光粉合成工艺与光谱特性的关系模型；基于荧光光谱和拉曼光谱，建立激发态下的光学跃迁模型，阐释荧光粉中多种跃迁机理和荧光猝灭等效应；建立WLED光色性能评价模型，获得高效高显色性WLED用荧光粉配色方案数据库；实验上，研究中间产物可调的多步高温固相合成技术及基于ALD的介质膜包覆技术对荧光粉光谱性能的影响机理，合成出匹配LED芯片、光谱可调的高效荧光粉，建立多层次荧光粉样本数据库；基于色度学原理与光色性能优化评价模型，建立匹配蓝光/近紫外芯片的荧光粉配色调控数据库；结合一体化封装实验，制备高效高显色WLED器件。结合理论建模、数值计算、实验等手段，实现高效高显色性WLED技术。

为推进白光LED光效、显色性能及相关色温等系统性研究，开发兼具高效高显色的白光LED器件，本项目开展了白光LED用荧光粉合成及表面处理技术，以及荧光粉配色调控机理的研究。通过将LiSi2N3引入CaAlSiN3:Eu2+中获得了Ca1-xLixAl1-xSi1+xN3:Eu2+固溶体宽光谱红色荧光粉，提高了量子效率和热稳定性，获得了兼具高效（101 lm/W）高显色（Ra=95，R9=96）的白光LED；通过将SiC引入AlN:Eu2+结构中制备出Al1−xSixCxN1−x:Eu2+高光效高稳定蓝色荧光粉，外量子效率和吸收效率分别可以达到61%和74.4%，相比目前的氮化物荧光粉提高了11-15%；通过在红色氮化物荧光粉Sr2Si5N8:Eu2+中引入C形成Si-C键，提高了其发光效率和稳定性，荧光粉热致光衰从16%减小到0.8%，300℃时的量子效率仅降低7%；受邀在Chemical Reviews杂志上发表有关氮化物发光材料及其应用的最新综述；基于ALD技术，研究了荧光粉表面处理工艺，制备出了高效高可靠性YAG:Ce3+@SiO2和YAG:Ce3+@TiO2荧光粉；通过In2O3包覆，提高了β-sialon:Eu2+的电致发光强度，同时减少了其发光饱和；提出了一种优化的pc-WLED光谱模型，优选出了色温CCT在4000-5000K范围内的具有S/P（2.0-2.14）、Ra>80优良光色特性的封装方案。采用蓝光LED芯片激发β-sialon:Eu2+绿色荧光粉和窄带KSF:Mn4+红色荧光粉，得到色温为11184-13769 K，发光效率91-96 lm/W，色域达到NTSC标准94.3-96.2%的背光源；通过光谱设计和仿真计算指导，采用双红色荧光粉（宽光谱CaAlSiN3:Eu2+和窄带K2SiF6:Mn4+）代替通常单一红色荧光粉，获得了发光效率>115lm/W，Ra=97，R9=96的白光LED器件。相关成果在国内外权威学术刊物上公开发表论文共29篇，其中二区及以上高质量论文19篇，SCI收录28篇，中文核心收录1篇；申请发明专利15项，其中已授权发明专利11项，已公开发明专利1项，已授权实用新型专利3项及软件著作权3项。本项目全面完成了预期的研究成果，研究出的理论成果和配色封装技术在白光LED领域拥有较好的应用前景，并获得了行业的肯定。