基于非视觉功能的LED远红光-近红外荧光材料合成及发光特性研究

In the latest round of science and technology updating and industry transforming for the strategic emerging industry of semiconductor lighting, China has already been in the forefront of world but still faces the severe challenge of continuous renewal in technology. In addition to lighting, the functional application of LED becomes more and more important in daily lives, which requires the novel phosphors must be developed promptly so as to support the development of LED industries. Aiming to the potential application of next-generation LEDs in photomorphogenesis of plants, eyesight health, iris recognition and food safety detection, this project will explore new far-red and infrared phosphors for LEDs. To develop the phosphors with desirable emission wavelength which matches for the absorption wavelength of 730 nm of the Pfr isomer of phytochrome, the 700-850 nm for retinal cells repair and regeneration, 810 nm for iris recognition, et al, this work will preferentially investigate the luminescence of Cr3+ and Yb3+ in fluoride compounds and the next in oxyfluorides and garnet-structure oxides. The phonon scattering in fluorides is low, which is helpful to improve luminescence efficiency. The strategy of soft-chemical approach assisted with high-temperature solid-state reaction will be employed to synthesize phosphors. Combining the experimental approaches of long-range average structure investigated using XRD and the short-range local structure examined by EXAFS with theoretical calculation on band structure, et al, this project will give a systematical study on the crystal and electronic structures and luminescence mechanisms of obove optimized phosphors. Finally, the LED devices will be packaged by using the optimal phosphors to test their reliability. The original research on far-red and near-infrared phosphors achieved in this project will make a positive contribution to supporting and leading the future-development of LED industry in China.

在新一轮科技升级和产业变革中，我国半导体照明战略性新兴产业已经走在世界前列，但依然面临持续技术更新的严峻挑战。LED功能化日益突出，亟需开发新型荧光材料。本项目瞄准下一代LED在植物光控发育、人眼视力健康、虹膜识别和食品安全检测方面的应用，探索合成远红光-近红外发光新型材料。为满足光敏色素Pfr态吸收波长峰值730nm、视网膜细胞修复与再生所需700-850nm、虹膜识别所需810nm等波长，本项目将优先研究Cr3+与Yb3+在声子能量较低的氟化物体系发光，其次是氟氧化物与石榴石结构氧化物。采用软化学法与高温固相反应相结合的控制合成路线，利用XRD对宏观均匀结构和EXAFS对微观局域结构与理论计算相结合的方法，对合成材料的晶体结构、电子能带结构和发光机理进行系统研究。最后，通过LED器件封装验证材料可靠性。本项目在远红光-近红外材料方面的原创性研究将为我国LED产业发展起到支撑和引领作用。

本项目在执行期间，系统性研究了氟化物体系(K,Na)3(Al,Ga)F6:Cr3+/Yb3+、氧化物β-Ga2O3:Cr3+、石榴石结构体系(Y,Gd)3(Al,Ga,Sc)5O12:Cr3+、碳酸钙镁石结构体系RE(Sc,Ga)3(BO3)4:Cr3+ (RE为稀土) 、稀土钙钛矿结构体系RE(Ga,Sc)O3:Cr3+、类钙钛矿体系Li(Sc, Ga, Al)MO2:Cr3+、尖晶石结构(Mg,Ga)(Ga,Sc)2O4:Cr3+、铌酸盐(Mg,Zn)4Nb2O9:Cr3+、以及(Li,Na)ScSi2O6:Cr3+的合成与发光特性，包括光吸收、激发、发射与器件封装性能，并对发光机理进行了深入研究，揭示了影响Cr3+发光性能的因素，为开发新红光-近红外荧光材料奠定重要理论与实验基础。进而，发展了新型红光-近红外光LED器件封装技术。封装出红光-近红外光LED器件在20 mA驱动下，光电效率最高达到29.87%；在100mA驱动下辐射光功率为75.5mW，光电转换效率为25.62%。.本项目在探索高效红光-近红外光荧光粉和LED器件方面取得重要突破，为产业化奠定重要基础。分别将荧光粉和LED器件封装研究成果交给企业代工，已制作出两种类型的LED灯珠。利用研制的光源，开展了大量的光学农业和光生物医学研究，采用基因转录等手段揭示信号传导机制。据生物医学研究成果，进一步开发了青少年近视光生物治疗仪。该产品已经投入临床试验。.本项目探索了稀土铁/锰酸盐RE(Fe,Mn)O3窄带隙氧化物半导体的合成、晶体与电子结构以及半导体性能；面向显示器背光源应用，发展了K2TiF6:Mn荧光粉的二次结晶合成方法，显著提高了发光效率。探索了环境稳定的无机非金属量子点BN、C3N4量子点控制合成以及电致发光性能，发展了无机非金属量子点制备方法，以这些量子点为发光层制作出电致发光QLED原型器件。.在执行期内，发表论文12篇；撰写2本专著章节；申请专利19件，其中美国发明专利1件、澳大利亚革新专利2件、国际PCT专利3件、国家发明专利10件、国家实用新型专利3件；参加国际国内学术会议交流24人次，其中参加国际学术会议8人次；培养在读博士后1、在读博士生1人，培养硕士14人，其中10人已经获得硕士学位；获省部级奖励4项，获国际组织奖2项。.本项目研究成果对引领我国LED产业发展具有重要意义。