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Tb ~ (3 +) Doping Of Zno-b <sub> 2 </ Sub> The O <sub> 3 </ Sub>-sio <sub> 2 </ Sub> Glass Long Afterglow Mechanism

Posted on:2006-06-19Degree:MasterType:Thesis
Country:ChinaCandidate:X R GuoFull Text:PDF
GTID:2191360152971859Subject:Materials science
Abstract/Summary:PDF Full Text Request
This thesis reviews the history of long-lasting phosphorescent materials comprehensively, presents its recent progress and summarizes the long-lasting phosphorescent mechanism. On the basis of this summarization we chose Tb3+ doped ZnO-B2O3-SiO2 (ZBS) glass as research object and analyzed systematically the long-lasting phosphorescent mechanism of samples and the effect of transitional metal ions on traps in the samples by fluorescent spectra, afterglow decay curves, thermoluminescence spectra and UV-visible spectra etc.We discussed the long-lasting phosphorescent mechanism of Tb3+ doped ZBS glass from four aspects of absorbing energy, saving energy, conveying energy and releasing energy. Simultaneously, we settled several problems about type, depth and energy level distribution of traps in the glass, transmitting route and conversion mode of energy. We also established Half Tunneling model of the long-lasting phosphorescence by related mechanism. This model of mechanism tells us that the long-lasting phosphorescence of Tb3+ doped ZBS only has a connection with the traps of shallow energy which take on exponential distribution in energy level, and that the different traps in energy level depth correspond with different process of afterglow decay. It also tells us that the excitated electrons are ultimately captured by traps through conduct band, and that the electrons running away from traps tunnel into luminescent ions through 5d-energy band.On the basis of related mechanism, long-lasting phosphorescent performance of materials has many decisive factor. Materials are provided with the certain route of energy transmitting, the certain mode of energy conversion and appropriate traps when glass samples and luminescent ions are fixed. Depth and density of traps and long-lasting phosphorescent performance of materials will have great change with addition of microelements or new elements. The experiment results indicate that the long-lasting phosphorescent and photochromism property of samples have the synchronous change with compositions. We put forward an idea that betterlong-lasting phosphorescent glass systems are found from better photochromism glass systems.So we chose transition metal ions-Ti,Zr,Ag as doping ions which have an impact on photochromism behavior of glass and studied the effect of the microelements on long-lasting phosphorescent performance of Tb3+ doped ZBS glass. The experiment results indicate that the traps of glass in space and energy level and long-lasting phosphorescent performance in life and intensity have great change with addition of Ti,Zr,Ag. We advance that optional doping of metal ions can realize controllable and adjustive function of traps in Tb3+ doped ZBS glass and new applications of glass materials in information field by discussing diverse rule of traps. We have done preparatory and exploring research about transition metal ions doping.
Keywords/Search Tags:long-lasting phosphorescent glass, luminescent mechanism, luminescent model, electron trap, ions doping, assistant activator
PDF Full Text Request
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