本研究利用固態法合成磷酸鹽類螢光材料，本文主要針對下轉換與上轉換這兩部份機制及其應用來探討之，第一部份主旨在開發可適用於紫外光發光二極體(UV-LED)之新穎組成的螢光體，我們成功合成了可用紫外光波長激發之磷酸鈣釔鋱(Ca9Y1-xTbx(PO4)7)(x=0.005~0.5)以及可用紫外光波長和藍光波長激發之磷酸鈣釔銪(Ca9Y1-xEux(PO4)7)(x=0.03~1)。主要以磷酸鈣釔(Ca9Y(PO4)7)為主體材料，分別摻雜鋱(Tb3+)、銪(Eu3+)稀土元素為發光中心，研究添加不同濃度之發光中心離子，其發光機制與濃度淬滅(concentration quenching)效應，並以X光粉末繞射、螢光光譜儀及紫外-可見光擴散式反射光譜儀鑑定其結構與發光特性。
磷酸鈣釔鋱(Ca9Y1-xTbx(PO4)7)(x=0.005~0.5)，在紫外光(370 nm)激發條件下，放射光之顏色落在藍綠~綠光範圍；在x=0.2時得到最強之綠光放射，其最強的波峰位於544 nm，CIE座標為(0.256,0.559)，外部量子效率QE最高為16.8%。磷酸鈣釔銪(Ca9Y1-xEux(PO4)7)(x=0.03~1)，在紫外光(395 nm)激發條件下，放射光之顏色落在橘紅光~紅光範圍，於x=1時獲得最佳放射光強度，其最強的波峰位於613 nm，CIE座標為(0.635,0.355)，色純度可達到89.6%，外部量子效率QE最高為40.8%。並探討其熱穩定性，發現磷酸鈣釔鋱及磷酸鈣釔銪皆比商用螢光粉具有較佳之熱穩定性。最後我們將此兩種螢光粉體依重量百分比例混成可得到一近似白光之螢光粉體，其CIE座標為(0.322,0.333)。
在第二部份，我們期望利用螢光材料幫助吸收紅外光之波段，提升太陽能電池之光電轉換效率。故針對太陽能電池長波長之波段吸光特性相對薄弱的缺點，進而研發具上轉換(up-conversion)效益之螢光粉。在此我們選擇了YPO4、Ca3(PO4)2、LaPO4三種主體分別共摻雜Tm3+以及Yb3+離子，探討磷酸鹽類主體於980 nm雷射激發下之上轉換效應，並以X光粉末繞射和螢光光譜儀鑑定其結構與發光特性，最後藉由不同功率之激發來探討上轉換效應的機制。

The object of this study is to synthesize phosphate oxide based phosphors. Our experiment is mainly seperated to two parts. First is to develop a suitable phosphor powder which can apply to UV light-emitting diodes(UV-LED). We successfully composed Ca9Y1-xTbx(PO4)7 (x=0.005~0.5) and Ca9Y1-xEux(PO4)7 (x=0.03~1) which can be excited by UV wavelength. We use Ca9Y(PO4)7 as the host material, rare earth elements like Tb3+ and Eu3+ as the luminescence center. We adjusted various different concentrations of Eu3+ and Tb3+ ions to investigate its luminescence mechanism and concentration quenching effect.
The experiments show that the color of emitting light is located at the range of blue-green to green in Ca9Y1-xTbx(PO4)7 (x=0.005~0.5) phosphor under UV light (370 nm) excitation, which has green emission at 544 nm. The maximum integral emission intensity is obtained at 20 mol% (x＝0.2) Tb3+, its C.I.E coordinate is (0.256,0.559), and the highest external quantum efficiency QE up to 16.8%. The color of emitting light is located at the range of orange-red to red in Ca9Y1-xEux(PO4)7 (x=0.03~1) phosphor under 395 nm excitation, which has red light emission at 613 nm. The maximum integral emission intensity is obtained at 100 mol% (x＝1) Eu3+, its C.I.E coordinate is (0.635,0.335), and the highest external quantum efficiency QE up to 40.8%. We also investigated the thermal stability, and we found that no matter Ca9Y1-xTbx(PO4)7 or Ca9Y1-xEux(PO4)7, both of which have better thermal stability than commercial phosphors. Finally, we blended these two different phosphors in weight percent to obtain a near- white light, its C.I.E coordinate is (0.322,0.333).
In the second part, in order to enhance the photoelectric conversion efficiency of solar cell, we look forward to using fluorescent materials to help transform the infrared light to visible light. Hence, we have chosen YPO4, Ca3(PO4)2, LaPO4 as the host materials codoped with Tm3+ and Yb3+ ions, and investigated the up-conversion effect of phosphate based phosphors under 980 nm laser excitation. We found that blue emission(1G4→3H6) and red emission(1G4→3F4) conclude two mechanism：one is sequential mechanism, the other is cooperative mechanism. The near infrared(NIR) emission(3H4→3H6) also concluded two mechanism：one is sequential mechanism, the other is cross relaxation effect between Tm3+ ions.

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