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Phosphors and Devices in Application of GaN-based Power WLEDs

Author: GuTieCheng
Tutor: WangDaJian
School: Tianjin University of Technology
Course: Condensed Matter Physics
Keywords: White light-emitting diodes (WLEDs) High Phosphor Nitride Portland Chroma
CLC: TN312.8
Type: Master's thesis
Year: 2008
Downloads: 370
Quote: 6
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Abstract


Solid-state lighting, especially white light diode (WLEDs) light source for its energy saving, environmental protection and long life and other advantages, countries compete to become the focus of development technologies. High color and high power white LED diode is the current direction of development of the industry. In the realization of the many scenarios white LED, high efficiency blue LED single-chip high luminous efficiency phosphor structure, become a research hotspot. High stability as a fluorescent phosphor conversion material is to solve the high power white LED stability of a technology approach. Focuses on the power type WLEDs for the europium-activated orthosilicate and nitrides new fluorescent materials, the main results obtained are as follows: a) for the first time to spray pyrolysis and high temperature solid phase synthesis of pure phase, respectively, α'-Sr 2 SiO 4 : Eu 2 and β-Sr 2 SiO 4 : Eu 2 phosphors. 2) first discovered α'-Sr 2 SiO 4 : Eu 2 and β-Sr 2 SiO 4 : Eu 2 two fluorescent materials emitting performance differences were calculated using the formula Uitert two materials 5d-4f transition emission photon energy, and through Gaussian fitting Both materials were determined actual emission peak was 489.1 nm/555.1 nm, 468.8 nm/539.7 nm/593.2 nm, 593.2 nm emission peak which comes from the β-Sr 2 SiO 4 : Eu 2 in the phosphorescent emission. As two structures similar to the crystal, Ba 2 SiO 4 : Eu 2 and Sr3SiO5: Eu2 fluorescent materials are also successfully synthesized, and their luminescence properties were investigated. 3) high-temperature solid-phase method to synthesize the emission peak at 534 nm wide excitation spectrum, high conversion efficiency nitride fluorescent yellow-green material, have not been optimized experimental conditions, 460 nm when excited by blue light relative brightness of approximately YAG : Ce3 50%. 4) to nitride crystal structure of fluorescent samples were analyzed in detail. The use of polycrystalline powder diffraction was measured phase composition of the sample, and the sample may arise a new phase of the diffraction peaks indexing done to determine the phase of the crystal system and cell parameters; 5) of N compounds fluorescent material conditions for the preparation of a preliminary optimization study of sintering temperature, reducing atmosphere, cationic activator solution and on the spectral properties of the impact, as well as the sintering temperature between the sample morphology; 6) analysis of the above synthetic chromaticity properties of materials, according to color theory to calculate the production of different color temperature white LED fluorescent material required for the ratio of the brightness, and color rendering index of the corresponding WLED do simulation; homemade phosphor success with the above package white LED.

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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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