LED具有效率高、 体积小、 功耗低、 寿命长等优点, 并且因其具有可轻易实现宽幅光谱调控的特性, 在植物照明领域崭露头角。 植物照明用LED分为两大类, 一类是单色光LED, 另一类是白光LED, 其中植物照明用白光LED可与单色LED混合或者单独使用从而实现植物补光照明。 植物封装用白光LED大部分采用蓝光LED芯片或紫外LED芯片和荧光粉组合实现, 即荧光粉转换型白光LED, 但是光谱集中于可见光偏蓝, 对植物进行光合作用的效率不明显。 植物对于光的吸收不是全波段的而是有选择性的, 基于植物光合作用吸收光谱的特殊性, 将白光LED光谱的显色性能作为评判其光谱是否适合植物生长所需的光质的标准, 其平均显色指数Ra, 特殊显色指数R9(饱和红光), R12(饱和蓝光)被考虑选择为植物照明用白光LED的主要性能评价参数。 为设计出植物进行生长发育所需要的、 性能良好的能应用于植物照明领域的白光LED, 选用常见商用YAGG为绿色颜色转换材料, 选用(Sr, Ca)AlSiN3为红色颜色转换材料, 并用传统高温固相法制备了系列光谱可调的(Sr, Ca)AlSiN3荧光粉, 并进行了光谱性能分析。 通过将搭建好的LED结构模型导入光学仿真软件并分别引入绿色荧光粉颗粒、 红色荧光粉颗粒以及蓝光芯片的特性参数, 在Lighttools中分别建立了单蓝光LED芯片(450 nm)和双蓝光LED芯片(450+470 nm)激发(Sr, Ca)AlSiN3和YAGG荧光粉组合, 实现了白光LED的光学仿真模型, 研究了两种激发模式下仿真得到的不同色温白光LED的光谱功率分布及其显色性能。 用蓝光LED芯片、 (Sr, Ca)AlSiN3以及YAGG荧光粉组合进行了单芯片和双芯片显色性能差异的封装验证。 通过将Sr0.8Ca0.12AlSiN3∶0.08Eu2+和YAGG荧光粉的混合物点涂在双蓝光LED芯片上进行了白光LED的封装制备, 获得了Ra=91.2, R9=96.1, R12=78.9, 光谱辐射光效LER=126 lm·W-1的高效高显色白光LED其含有植物生长所需要的蓝光和红光。

LED has the advantages of high efficiency, small size, low power consumption, long life and son on, and it can easily achieve wide spectral regulation, which makes it stand out in the field of agriculture. Plant-growth light-emitting diodes (LEDs) can be divided into two categories, one is monochromatic LED, and the other is a White light-emitting diode (WLED), WLEDs used for plant growth are either mixed with monochromatic LED or used alone to realize plant supplementary lighting. Most of the WLEDs on plant growth is composed of a blue LED chip or a UV LED chip packed with phosphors, that is, phosphor-converted WLEDs, however, the obtained spectra are concentrated in the bluish visible light, and the efficiency of photosynthesis to plants is relatively poor. The absorption spectra of the plant are not full-band but selective, based on the particularity of the absorption spectra of plant, the color rendering performance of the spectra of WLEDs is regarded as the standard to judge whether the spectra are suitable for plant growth, the average color rendering index Ra, special color rendering index R9 (saturated red light) and R12 (saturated blue light) were considered as the main performance evaluation parameters of WLEDs on plant growth. In order to design WLEDs with good performance and can be used in the field of agriculture, common commercial YAGG was selected as green color conversion material and (Sr, Ca)AlSiN3 was selected as red color conversion material. (Sr, Ca)AlSiN3 red phosphors were prepared by traditional high temperature solid state method and the spectral performance was analyzed. By importing the built LED structure models into the simulation software LightTools and introducing the characteristic parameters of green phosphor particles, red phosphor particles and blue chip respectively, the simulation models of WLED were built based on a single blue LED chip (450 nm) and two blue LED chips (450+470 nm) separately , the color rendering performance of the spectral power distribution of WLEDs under different correlated color temperature was studied under the two excitation modes. In order to verify the difference of the color rendering index of the spectra obtained by the two excitation modes, WLEDs were prepared by combining (Sr, Ca)AlSiN3 and YAGG phosphors. Eventually, a real WLED was encapsulated by coating the combination of Sr0.8Ca0.12AlSiN3∶0.08Eu2+ and YAGG phosphors on two blue chips and led to an optimal spectrum of Ra=91.2, R9=96.1, R12=78.9, LER=126 lm·W-1 which contains the blue and red light needed for plant growth.