| Summary: | 博士 === 國立臺灣大學 === 化學研究所 === 99 === Examining the photoluminescence spectra, it was confirmed that the energy transfer from Ce3+ ions to Eu2+ rarely contribute to the luminescent enhancement of Li2SrSiO4:Ce3+,Eu2+. The proposed argument was validated with the first principle calculation about the defects formation energies. Furthermore, a mixture of Y3Al5O12:Ce3+ and CaAlSiN3:Eu2+ was coated on a blue light-emitting diodes (LEDs), the resultant white LEDs had a high luminous efficacy of ηL = 68 lm/W, a high color rendering index of Ra = 93, and a color temperature of CCT = 3,007 K (at 50 mA).
On the other hand, we also emphasized that the physical and chemical properties of UV-LED pumped phosphors such as phosphate ABPO4:RE (A = Li, K; B = Sr, Ba; RE = Eu2+, Tb3+ and Sm3+), BaY2Si3O10:RE (RE = Ce3+, Tb3+, Eu3+), ZnB2O4:Bi3+, Eu3+ and NaSrBO3:RE (RE = Ce3+, Tb3+, Sm3+). This study elucidated the crystalline structure and lattice parameters of the products via a solid state reaction, using powder X-ray diffraction (XRD) and general structure analysis system (GSAS) refinement. The density functional calculations are performed using the generalized gradient approximation plus an on-site Coulomb interaction correction (GGA+U) scheme to investigate the electronic structures of the KSrPO4 system.
Therefore, we proposed a novel mixture of variously colored quantum dots (InP) and silicone resin as a color-converting material, which can be applied to a UV-LED or Blue-LED chip. In the case of non-toxic InP QDs, the full color emission wavelengths can be easily adjusted by controlling the particle size (quantum confinement effect), and such QDs can be dispersed uniformly in silicone resin. This fact can perhaps be exploited to solve the problems of the efficiency and coating technology of LED devices.
|
|---|
