三價銪與鈰離子、三價鈰與鋱離子活化硼酸鹽螢光體之發光特性與能量轉移之研究

Synthesis, Luminescence and Energy Transfer of Bi3+, Eu3+ and Ce3+, Tb3+ Activated Borate Phosphors

馬艾莉(Irish-Valerie Maggay)

指導教授 ： 劉偉仁

中原大學/工學院/化學工程研究所/碩士(2015年)

https://doi.org/10.6840/CYCU.2015.00112

摘要

摘要
Tb3+與Eu3+之間的能量轉移在提升光學特性佔了很重要的角色，此篇研究主要分為兩大系列來探討硼酸鹽類螢光粉，第一部分為探討摻入紅色放光Bi3+、Eu3+與綠色放光Ce3+、Tb3+作為活化劑，探討其合成、光學特性與能量轉移機制，而第二部分為針對Eu3+、Tb3+的單摻進行研究，螢光粉分別為Li6Yb(BO3)3:Eu3+、Ba3Yb(BO3)3:Eu3+、Li6Yb(BO3)3:Tb3+，在白色發光二極體(w-LED)的應用具有潛力。
本研究首先是探討以固態反應法合成Sr3Lu2(BO3)4、 Li6Lu(BO3)3 、Ba3Y(BO3)3三種主體，分別摻雜了Bi3+與Eu3+、Ce3+與Tb3+，由X光繞射光譜儀與放光光譜儀分析其XRD圖譜、晶體結構、激發與放光光譜、熱穩定性與色度座標，第二部分則是針對Eu3+、Tb3+的單摻進行研究，螢光粉分別為Li6Yb(BO3)3:Eu3+、Ba3Yb(BO3)3:Eu3+、Li6Yb(BO3)3:Tb3+。
Bi3+有效的能量轉移至Eu3+提升其發光強度，此外，Eu3+在波長範圍為300nm到400nm具有寬帶的吸收光譜，此篇研究也探討了Bi3+在Bi3+ (I) (綠色)與Bi3+ (II) (藍色)兩種格位的影響，Ce3+被證明不僅是好的活化劑，更是有效的Tb3+敏化劑，可改善其放光強度，且其吸收光譜也適合以UV光激發。
敏化劑、活化劑之間的強烈相互作用，搭配相同的能階與光譜重疊加成是關鍵因素使其能夠有效的能量轉移，基於螢光粉涉及能量轉移其機制大部分皆屬於偶極-四極形式的能量機制。
除此之外，本研究成功的合成螢光粉藉由活化劑與敏化劑的共摻，可以大範圍的調控顏色，舉例來說像是從藍色到綠色、橙色到紅色或是橘色到紅色。

關鍵字

發光特性 ； 能量轉移 ； 固態合成法

並列摘要

Abstract
Energy transfer plays a key role in enhancing the optical properties of narrow emitting luminescent centers such as Tb3+ and Eu3+. This study mainly focuses on the synthesis and investigation of the photoluminescence properties and energy transfer mechanism of red emitting Bi3+, Eu3+ and green emitting Ce3+, Tb3+ activated borate phosphors for white light emitting diodes (w-LEDs) applications.
Sr3Lu2(BO3)4, Li6Lu(BO3)3 and Ba3Y(BO3)3 host phosphors were doped with Bi3+, Eu3+ and Ce3+, Tb3+ via solid state method. The X-ray diffraction patterns, crystal structure, photoluminescence emission and excitation, thermal stability and chromaticity coordinates were characterized by X-ray Diffractometer and spectrofluorometer. Eu3+ singly doped Li6Yb(BO3)3 and Ba3Yb(BO3)3; Tb3+ singly doped Li6Yb(BO3)3 were also investigated.
Bi3+ efficiently transferred the energy to Eu3+ by enhancing its luminescence intensity. Also, it broadened the absorption spectrum of Eu3+ in the range of 300 nm – 400 nm. Moreover, the influence of the two emissions of Bi3+ ions attributed to its Bi3+ (I) (green) and Bi3+ (II) (blue) site symmetry were also investigated. Ce3+ was proven to be not only a good activator but also an efficient sensitizer to Tb3+ by improving the luminescence intensity and broadening the absorption spectrum allowing it to be suitable for n-UV excitation.
Spectral overlap, strong interaction between sensitizer and activator ions, and matched energy levels are the key points in efficient energy transfer. Based on the gathered data involving the mechanism governing the energy transfer among the synthesized phosphors, dipole quadrupole type interaction dominated the transfer mechanism.Moreover, the successful co-doping between the sensitizer and activator ions, allowed a wider range of color tunability from blue to green, violet to red and orange to red.

並列關鍵字

Energy Transfer ； Solid State Synthesis ； Luminescence

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