紅色氟化物螢光粉光譜調變之機理探討暨應用

Spectra Tuning in Red Fluoride Phosphors via Mechanism Investigation and Their Applications

吳偉綸(Wei-Lun Wu)

指導教授 ： 劉如熹

國立臺灣大學/理學院/化學研究所/碩士(2017年)

https://doi.org/10.6342/NTU201700947

摘要

白光發光二極體(white light-emitting diodes; WLEDs)已被廣泛應用於全球不同之照明系統，因其具高亮度，低能耗，高耐用性與環保性。為提高裝置顯色指數（CRI），須添加紅光螢光粉豐富紅色光譜區域。氮化物螢光粉為WLED器件中常用之紅色螢光粉。然而人眼對幾乎無法檢測出650 nm以上之紅光。故氟化物螢光粉具窄光譜放射與適當之峰值位置630 nm，同時無黃綠光吸收可有效避免於元件中之光譜再吸收之能量所耗，基於以上之優點，氟化物螢光粉成為極具潛力之紅色螢光粉。但商用之氟化物螢光粉K2SiF6:Mn4+(KSF)其放射光譜中缺少正紅光620 nm之光譜貢獻，因此氟化物螢光粉之光譜改質仍為研究之重要方向。目前研究指出藉由氟化物螢光粉結構之扭曲可獲取額外之零聲子線放射光譜，此放射即位於620 nm之正紅光波段可進一步提升其紅色光譜貢獻。
本研究以化學共沉澱法合成同時具高量子效率與零聲子線放射之紅色氟化物螢光粉，利用X光繞射儀分析其晶體結構，探討其晶體結構與其電子躍遷選擇率之關係，藉此瞭解其放射光譜與零聲子線之放射機理。並以理論計算求得氟化物之理論能階，比擬實驗光譜之躍遷過程。本研究中亦量測粉體於不同環境中之光譜動力表現，藉此觀察零聲子線之變化趨勢，並分析螢光粉之動力緩解過程，此外亦嘗試調變氟化物螢光粉之主體結構，調控零聲子線之放射強弱，最終將所合成之氟化物螢光粉應用於白色發光二極體之中，並將之與商用KSF螢光粉進行比較，由其裝置表現中可知，藉由額外之零聲子線紅光貢獻，可有效提升白光裝置之演色性與其光視效能(Luminous efficacy of radiation)之照明表現。

關鍵字

窄光譜 ； 氟化物螢光粉 ； 零聲子線

並列摘要

White light-emitting diodes (WLEDs) have been widely used in different lighting systems around the world because of their high brightness, low power consumption, high durability and environmental protection. In order to improve the WLEDs color rendering index (CRI), must add red-light phosphors rich red spectral area. Nitride phosphor is a red phosphors commonly used in WLED devices. However, the human eye is almost impossible to detect more than 650 nm red light. Fluoride phosphors with narrow spectral emission and the appropriate peak wavelength of 630 nm, moreover, no yellow-green light absorption can be effectively avoided in the components of the spectrum of re-absorption of energy consumption, based on the above advantages, fluoride phosphors has great potential applied to WLEDs system. However, the commercially fluoride phosphors K2SiF6:Mn4+ (KSF) lacks the spectral contribution of the positive red light at 620 nm in the emission spectrum. Therefore, the spectral modification of the fluoride phosphors are still important direction. At present, it is pointed out that with the additional zero phonon emission spectrum can be obtained by the distortion of the fluoride phosphors structure, which is a positive red light band at 620 nm to further enhance its red spectral contribution.
In this study, the red fluoride phosphors with high quantum efficiency and zero-phonon radiation was synthesized by chemical co-precipitation method. The crystal structure was analyzed by X-ray diffractometer. The relationship between the crystal structure and its electron transition process was discussed. To understand its radiation spectrum and zero-phonon radiation mechanism. The theoretical step of fluoride was obtained by theoretical calculation, and the transition process of the experimental spectrum was compared. In this study, we also measured the spectral lifetime of the powder in different environments, observed the trend of the zero-phonon line, and analyzed the mitigation process of the fluoride phosphors. In addition, we tried to adjust the main structure of the fluoride phosphors. The control of the zero-phoneme radiation intensity, and ultimately the synthesis of fluoride phosphors used in white light-emitting diodes, and with the commercial KSF phosphor powder comparison, the performance of its device can be seen by the additional zero phonon red light contribution, can effectively enhance the white light device color rendering and its Luminous efficacy of radiation (LER) of the lighting performance.

並列關鍵字

line spectra ； fluoride phosphors ； zero phonon line

參考文獻

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