應用於發光二極體之紅色氮化物螢光粉合成與配方調控

早期所發展之白光發光二極體以藍光晶片激發黃色螢光粉所結合出白光，對應太陽光譜時，由於缺少紅色波段放光，對於暖白光需求較為困難，故近年研究發展以紅色螢光粉為主要導向。本論文利用化學取代與基礎合成條件對當今較熱門之紅色氮化物螢光粉進行改質，同時研究其化學特性與理論探討。Sr2Si5N8:Eu2+ 紅色螢光粉具620奈米放光，為理想之橘紅光源，以基本合成條件做為改良方式，維持其放光波段不受化學取代改變，並同時於合成時間調控中發現Sr2Si5N8:Eu2+ 與 SrSi6N8:Eu2+ 之間相轉變過程，以成功合成出同時具藍光與紅光放光之複合性螢光粉材料。CaAlSiN3:Eu2+亦為高穩定材料之一，其放光波段位於650 奈米，於此嘗試利用Sr取代Ca之化學取代方式將波段藍移至理想之620奈米，透過同步輻射之晶格與價態分析，搭配固態核磁共振與拉曼光譜觀察此體系中結構重組並形成有序結構之轉換過程。Sr[LiAl3N4]:Eu2+具較窄帶放光光譜，減少人眼較不敏感之紅外光區放光，產生純度更高之紅光。我們嘗試利用表面修飾減少此螢光粉之耐水性問題，藉由二氧化矽修飾成功提升耐水性與空氣中之穩定性，並提高其放光效能，亦為首次利用高壓合成法合成出該紅色螢光粉材料，在高濕高溫條件之下證明其表面修飾有助於提高穩定性，進一步以理論計算與電子結構模型推斷出活化中心價態轉變之現象，提出具泛用性之理論基礎架構。

關鍵字

紅色螢光粉； LED ；固態反應

並列摘要

Traditional WLEDs are fabricated using blue chip and yellow phosphor to produce white light, with high efficiency but poor color rendering index (CRI) because of the lack of a red component. In this work, using chemical substitution and synthesis conditions on the basis red nitride phosphors, while theoretical discussion of their chemical properties. The light emission of Sr2Si5N8:Eu2+ at 620 nm, the orange light is ideal to red source. The properties of Sr2Si5N8:Eu2+ can be tailored by tuning the pressure, temperature, and sintering time in the basic sintering process. In the synthesis of Sr2Si5N8:Eu2+, Sr2Si5N8:Eu2+ was converted into SrSi6N8:Eu2+ during heating. CaAlSiN3: Eu2+ is also one of the highly stable material, which is located 650 nm. (Sr,Ca)AlSiN3:Eu2+, was developed through cation substitution and blue shift to 620 nm of peak position. Distortion of the lattice structure introduced adequate space and highly coordinated sites in the Sr/Eu centers for charge variation effect. Subsequently, typically arranged variations of the SiN¬4 and AlN4 clusters were formed in the lattice by Raman and ssNMR technique. SrLiAl3N4:Eu2+ presents a narrow band red phosphor for reducing near infrared region emission. In this study, SrLiAl3N4:Eu2+ red phosphor was prepared through a high-pressure solid-state reaction and was coated with organosilica layers to improve water resistance. The coated samples exhibited excellent moisture resistance while retaining external quantum efficiency in high temperature and high humidity. This study provides valuable information on the stimulation of nitride phosphors in LEDs

並列關鍵字

red phosphor ； LED ； solid state

參考文獻

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國際替代計量

應用於發光二極體之紅色氮化物螢光粉合成與配方調控

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