Research On Chalcogenide (halo) Glass Of Light-induced Effect And Ionic Conductivity

The thesis emphasizes on photoinduced optical properties and ionic conductivity property of chalcohalide and/or chalcogenide glasses. First, the photoluminescence properties of different rare-earth and transition metal ions doped Ge-Ga-S-CsCl chalcohalide glasses are investigated. Second, photoinduced darkening and bleaching of Ge-Se chalcogenide films are studied. At last, the physical and chemical properties as well as ionic conductivity of new chalcohalide glass system Ge-Ga-S-Agl-Ag are researched. Main achieved results are listed as follow:Eu2+single doped chalcohalide glass can emit a broad peak centered at433nm under the excitation of395nm only when the CsCl content of glass is up to40mol.%, while the emission of Mn2+single doped chalcohalide glass transits from green to red as the concentration of Mn2+increases upon447nm excitation. Notably enhanced Mn2+yellow emission is observed in CsCl modified and Eu2+/Mn2+codoped Ge-Ga-S glasses under395nm excitation. The plausible efficiency of energy transfer (ET) from Eu2+to Mn2+is as high as91%, which is obtained by measurement of luminescence decay of Eu2+in samples doped with and without Mn2+. The Eu2+/Mn2+codoping significantly increases the excitation cross-section at the NUV region, which is at heart of the enhanced Mn2+yellow emission. The ET processes responsible for the enhanced luminescence are discussed.Excitation, emission and decay spectra are measured to prove the occurrence of near-infrared (NIR) quantum cutting involving the emission of two NIR photons for each visible photon absorbed from Ce3+/Yb3+codoped chalcohalide glasses. The maximum ET efficiency from Ce3+to Yb3+obtained is as high as82%. The directly measured and calculated quantum yield (QY) of Yb3+emission is up to119%. The possible mechanism of ET is discussed. Besides, Excitation, emission and decay spectra are measured to prove the occurrence of near-infrared (NIR) quantum cutting of Eu2+/Yb3+codoped chalcohalide glasses.The maximum ET efficiency obtained is as high as85%. The ET from Eu2+to Yb3+is followed by dipole-dipole interaction. The possible mechanism of ET is also discussed.Near infrared luminescence properties of Bix Tm3+-doped and Bix/Tm3+co-doped70GeS2-10Ga2S3-20KBr chalcohalide glass samples are investigated by the absorption and photoluminescence spectra. The enhanced emissions at1230and1470nm have been observed from Bix Tm3+co-doped samples when pumped by an808laser diode. The possible energy transfer mechanisms from Bix to Tm3+ions are proposed.Photo-induced effects of GeSe2and Ge2Se3films illuminated in air and in vacuum are investigated by in-situ transmission spectra measurements. Both compositions exhibit photobleaching (PB) when exposed to bandgap laser for a prolonged time in air. By comparing with the photoinduced effects in vacuum, PB in Ge2Se3film results from surface photo-oxidation, whereas intrinsic structural changes dominate the PB in GeSe2film.Photosensitivity of thermally evaporated chalcogenide amorphous films of xGe45Se55-(1-x)As45Se55(x=0,0.25,0.5,0.75,1) composition is investigated when exposed to the laser light of660nm wavelength. The photo-induced effects transition from photodarkening (PD) to photobleaching (PB) as Ge4sSe55x increases from0to1. The degree of PB correlates with the concentration of Ge-Ge homopolar bonds. The kinetics of PD and PB can be well described by a stretched exponential function. The dynamic response of PB is much faster than that of PD films in the present glass system.The new chalcohalide glass system Ge-Ga-S-AgI-Ag is investigated by the measurement of density, X-ray diffraction, raman spectra, chemical stability, visible-near infrared-infrared transmission spectra as well as ionic conductivity. The doped Ag metal content in the system is up to20mol.%. The chemical stability of the glass system in air is much better than the same composition of Ge-Ga-S-CsI and Ge-Ga-S-Lil. The contribution of AgI to ionic conductivity is also discussed based on the structure analysis.