Synthesis and Characterizations of Novel Ultraviolet-Emitting Phosphors Using Synchrotron Radiation
|關鍵字:||紫外光螢光體;真空紫外光;光致發光;Ultraviolet-emitting phosphors;Vacuum ultraviolet light;Photoluminescence|
一般而言，在172 nm波長激發下，波長為313 nm之UVB紫外光發射源自Gd3+ 4f 7→4f 7躍遷；另一方面，UVC紫外光的發射源自Pr3+ 4f 15d1→4f 2躍遷，其放射波長深受主體環境與晶體結構特性的影響。|
Facing 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 develop environmental friendly 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 nine series of UV-emitting phosphors, including rare earth-doped silicates, 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 UVB-emitting KBa(Y,Gd)Si2O7, KBa(Y,Gd)(BO3)2, Ca4(Y,Gd)O(BO3)3, Na3(Y,Gd,Pr)(BO3)2, KCa(La,Pr,Gd)(PO4)2 and KSr(Y,Pr,Gd)(PO4)2 and UVC-emitting KCa(La,Pr)(PO4)2 and KSr(Y,Pr)(PO4)2. Under excitation at 172 nm, KBa(Y,Gd)Si2O7, KBa(Y,Gd)(BO3)2, Ca4(Y,Gd)O(BO3)3, Na3(Y,Gd,Pr)(BO3)2,KCa(La,Pr,Gd)(PO4)2 and KSr(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+.Under the same excitation, KCa(La,Pr)(PO4)2 and KSr(Y,Pr)(PO4)2 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.