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Infrared Excitation YAG:RE3+ Materials for White LED

Author: WangShaoYan
Tutor: ShenYi
School: Hebei University of Technology
Course: Materials Science
Keywords: YAG up-conversion rare earth ion sol-gel
CLC: TN312.8
Type: Master's thesis
Year: 2009
Downloads: 38
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Abstract


RE3+（RE=Er、Ho、Tm）-doped Y3Al5O12 （YAG） materials will be applied abroad to infrared excitation white LED. In the experiment, samples of YAG:RE3+ were prepared by sol-gel method; up-conversion luminescence and up-conversion mechanism were described, and some effective factors of up-conversion luminescence were investigated, including active ion, excitation current and the matrix composition.Samples of YAG:RE3+ materials were prepared by a sol-gel method which includes preparing Y3Al5O12 and doping active ion RE3+. At last, technologic parameter of sol-gel process and sintering conditions of YAG:RE3+ materials were determined.The characteristic structure of YAG and doping conditions of active ion RE3+ were described by XRD, FT-IR, TG-DTC and TEM. The structure of RE3+-doped YAG materials was also cubic.The up-conversion emission was discussed by absorption spectrum and up-conversion emission spectrum. The up-conversion spectroscopic properties of the YAG: RE3+ materials were investigated under the excitation of a 980 nm continuous wave diode laser. When active ion was Er3+, strong red and green up-conversion emissions which centered at 666nm and 552nm respectively were observed. The red and green emission respectively was assigned to the transition of energy levels 4 F9 /2→4I15/2and 4 S 3/2→4I15/2of Er3+ ions. When active ion was Ho3+, strong green up-conversion emissions which centered at 547 nm was observed. The green emission was assigned to the transition of energy levels 5 F4→5I8of Ho3+ ions. When active ion was Tm3+, strong blue up-conversion emission which centered at 487 nm was observed. The blue emission was assigned to the transition of energy levels 1 G 4→3H6of Tm3+ ions.The up-conversion emission spectrum of YAG:RE3+ materials indicated that the up-conversion emission intensity of YAG:RE3+ materials ascended as rare earth ion concentration increased. And the contemporaneous event was that the up-conversion emission intensity of YAG:RE3+ materials ascended as excitation current increased.

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CLC: > Industrial Technology > Radio electronics, telecommunications technology > Semiconductor technology > Semiconductor diode > Diodes: structure and performance > Light-emitting diodes
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