新穎紫外光螢光體之製備及發光特性之研究

Abstract

為因應綠色環保與永續發展之潮流，本研究之主旨為合成與開發具新穎性真空紫外波長可激發之放射紫外光(波長200-400 nm)螢光體，並探討其發光特性、原理與機制以及評估其在紫外線殺菌元件之應用潛力。本論文所探討之重點為可供準分子氙氣放電燈激發之磷酸鹽與硼酸鹽為主體之紫外光螢光材料。 本研究利用X-光繞射與電子顯微鏡進行螢光材料特性鑑定分析，同時亦利用同步輻射中心真空紫外光源進行螢光體之發光特性鑑定。本研究製備了發光波長屬UVA之K3(Y,Ce)(PO4)2、UVB之K3(Y,Gd,Pr)(PO4)2、(Ca,Gd,Pr)10K(PO4)7與KCa(Y,Pr,Gd)(PO4)2以及UVC之K3(Y,Pr)(PO4)2、KCa(Y,Pr)(PO4)2與(Ca,Pr,Na)10K(PO4)7。 在172 nm波長激發下，K3(Y,Ce)(PO4)2發生源自Ce3+ 5d1→4f 1躍遷，波長為340 nm之UVA紫外光；K3(Y,Gd,Pr)(PO4)2、(Ca,Gd,Pr)10K(PO4)7與KCa(Y,Pr,Gd)(PO4)2在相同激發條件下發射源自Gd3+ 4f 7→4f 7躍遷，波長為313 nm之UVB紫外光；而K3(Y,Pr)(PO4)2、KCa(Y,Pr)(PO4)2與(Ca,Pr,Na)10K(PO4)7則發射源自Pr3+ 4f 15d1→4f 2躍遷之UVC紫外光，其放射波長深受主體環境與晶體結構特性的影響。

To cope with the challenge of global warming and environmental concern, the development of green luminescent materials has been an important issue in phosphors research. This research is attempted to explore and investigate new UV-emitting materials, particularly those are not disclosed previously in the literature and excitable with xenon excimer discharge devices, for the applications of phototherapy, sterilization, and disinfection. We have explored and investigated the luminescence mechanism of four series of UV-emitting phosphors, including rare earth-doped phosphates and borates. In addition to X-ray diffraction technique and electron microscopy, the vacuum ultraviolet (VUV) light source provided by National Synchrotron Radiation Research Center (NSRRC) has been used to explore and investigate the luminescence of UV-emitting phosphors, such as UVA-emitting K3(Y,Ce)(PO4)2; UVB-emitting K3(Y,Gd,Pr)(PO4)2 and (Ca,Gd,Pr)10K(PO4)7, KCa(Y,Pr,Gd)(PO4)2 and UVC-emitting K3(Y,Pr)(PO4)2, KCa(Y,Pr)(PO4)2 and (Ca,Pr,Na)10K(PO4)7. Under excitation at 172 nm, K3(Y,Ce)(PO4)2 emits UVA radiation centered at 340 nm, which is attributed to the 4f1→5d1 transition of Ce3+. Under the same excitation, (K3(Y,Gd,Pr)(PO4)2, (Ca,Gd,Pr)10K(PO4)7 and KCa(Y,Pr,Gd)(PO4)2 were found to emit UVB light centered at 313 nm, which was attributed to the 4f 7→4f 7 of Gd3+. K3(Y,Pr)(PO4)2, KCa(Y,Pr)(PO4)2 and (Ca,Pr,Na)10K(PO4)7 were found to emit UVC light, which was found to be due to the 4f15d1 →4f 2 transition of Pr3+. The emission wavelength of all types of UV radiation was found to be crucially dependent on the chemical compositions, bonding and crystal structure of the host matrix.