White light-emitting diodes doped with rare-earth phosphor synthesis and properties

Title: White light-emitting diodes doped with rare-earth phosphor synthesis and propertiesAuthor: Hu OnoDegree-granting units: Nanchang UniversityKeywords: white LED;; doping;; rare earth phosphors;; strontium silicate lithium;; zinc molybdateSummary:White light emitting diodes (WLEDs) With high efficiency, long life, high stability and small size, and many other advantages of being the people's attention. As a promising solid-state lighting source, the light efficiency and color parameters and the price is the most important indicators. The decisions of these indicators is outside the LED chip and the fluorescent coating on Neodymium magnets the chip conversion materials. This study is to synthesize many can be an effective blue or near-UV excitation of new phosphors. Choose Li2SrSi04: Eu2 and ZnMoO4: Eu3 for the study two types of phosphor, the phosphor by doping to improve the brightness and type of tuning the excitation and emission wavelengths.Li2Sr0.995SiO4: 0.005Eu2 is a Blu-ray can be (400-480 nm) the effective excitation and emission peak at 580 nm or so out of the yellow phosphor. Our results demonstrate that: by PO43-and SO42-doping can significantly improve the luminous intensity, the optimum composition of Li2Sr0.995 (SiO4) 0.9775 (P04) 0.03:0.005 Eu2 and Li2Sr0.995 (SiO4) 0.945 (SO4 ) 0.11:0.005 Eu2. Excitation at 460 nm, and their luminous intensity are Li2Sr0.995SiO4: 0.005Eu2 | 1.8-and 2.2-fold. And SO42-doped also make the strongest excitation and emission spectra of the peaks 412 and 580 nm moved to 460 and red 610 nm, blue LED chip to make it more suitable for red light excitation and emission. The Pr3 doped Li2Sr0.995SiO4: 0.005Eu2 can also be enhanced in blue (452 ​​nm) excitation efficiency in the red zone (610 nm) emission intensity. And that Pr3-doped Li2SrSiO4 is a single blue LED can be efficiently excited by the red phosphor.Synthesis can be blue (466 nm) and near-UV (395 nm) while effectively stimulate the ZnMoO4: Eu3 series of red phosphor (emission peak 615 nm). Our goal is to charge compensation through the incorporation of Li as an agent, the incorporation of (Bi3, Sm3) or (La3, Y3, Gd3) to replace part of the Zn2, thereby increasing the light-emitting phosphor http://www.chinamagnets.biz/Neodymium/Ball-Neodymium-Magnets.php excitation peak intensity and width. Adding that Li ion significantly increase the powder brightness, the best ratio of Zn0.5MoO4: Eu3 0.25Li 0.25; amount of Bi3, Gd3 and Sm3 incorporation can further improve the luminous intensity, and the incorporation of the 395 Sm3 nm excitation peak has been significantly widened. Accordingly, the performance has been excellent Zn0.454MoO4: Eu3 0.25Li 0.25Bi3 0.04Sm3 0.006 and Zn0.44MoO4: Eu3 0.25Li 0.25Gd3 0.06 phosphor. The red phosphor excitation wavelength coincides with the existing Blu-ray and near-ultraviolet LED chip optical matching, in the blue and near ultraviolet LED chip white LED based on the great potential for application assembly.Degree Year: 2010