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Tunable Luminescence And Energy Transfer Process In Rare Earth/Transition Matal Ions Doped Glass/Glass Ceramics

Posted on:2018-12-08Degree:MasterType:Thesis
Country:ChinaCandidate:J J ZhangFull Text:PDF
GTID:2321330518474959Subject:Condensed matter physics
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Inorganic luminescent materials are important class of functional materials and have been widely used in daily energy-efficient lighting,display and other fields.In recent years,luminous glass and glass ceramic have been deeply investigated due to their potential applications in many fields,such as white LEDs,temperature sensing,optical sensors,scintillator detectors,solar cells and so on.In this paper,transparent glass ceramics containing Sr2GdF7 nanocrystals were successfully prepared by traditional melt quenching technique.By the co-doping of Ce3+,the upcoversion emission of Ho3+ ions in Yb3+/Ho3+co-doped samples is adjustable.In Sb3+/Eu3+ co-doped magnesium sodium-phosphate glasses,tunable emission and the white light emission are obtained by varying the concentration of Eu3+ ions.In Sb3+/Mn2+ co-doped magnesium sodium-phosphate glasses,with the increasing of Mn2+ content,the luminous color of the glasses change from blue to white,and finally to pure red.The main contents of this thesis are as follows:1.Yb3+/Ho3+/Ce3+ doped Sr2GdF7 oxyfluoride glass ceramics:Yb3+/Ho3+precursor glasses were successfully fabricated by traditional melt-quenching method.The precursor glasses were heat treated to form oxyfluoride glass ceramics containing Sr2GdF7 nanocrystal.Their microstructural and upconversion properties were systematically investigated by XRD,TEM,upconversion spectra and lifetime measurements.After heat-treatment,the upconversion luminescence intensity of Ho3+ in glass ceramics is enhanced about 1000 and 12 times for green and red emissions,respectively.The enrichment of Ho3+ into Sr2GdF7 lattice functioned the enhanced upconversion.Ipressively,a simple strategy of doped with Ce3+ ions can increase the red emissson of Ho3+ and suppress the green emission,realize multicolor tuning of Ho3+.The red to green emission ratio of Ho3+ was increased from?0.2 to?50.The color tunable phenomenon results from efficient cross-relaxation processes between Ho3+ and Ce3+.2.Tunable luminescence in Sb3+/Eu3+ co-doped phosphate glasses:highly transparent magnesium sodium-phosphate glasses have been successfully prepared using the melt-quenching method.The nominal composition of glass was 60P2O5-35MgO-5Na2CO3.Their luminescent properties were systematically investigated through absorption,excitation and emission spectra.Result show that the transmittance in the visible range is about 85%.Upon 278 nm excitation,tunable emission from blue to white and finally to yellowish red is obtained by varying the concentration of Eu3+.The results indicate that Sb3+/Eu3+ co-doped sodium-phosphate glasses may be applied in photo-converter under UV-LED excitation.3.Tunable luminescence in Sb3+/Mn2+ co-doped phosphate glasses:Sb3+/Mn2+co-doped highly transparent phosphate glasses were successfully fabricated by melt-quenching technique.Upon 278nm excitation,the varied emission from blue to white and finally to red is obtained by tuning the concentration of Mn2+.The energy transfer from Sb3+ to Mn2+ is proved by the excitation spectra and emission spectra.The highest energy transfer efficiency is calculated to be 98%.In addition,the Mn2+-Mn2+ distance became shorter with the increase of Mn2+ content.As a result,the ligand field strength surrounding Mn2+ is enhanced.The enhanced field make the excited state of Mn2+ gradually move closer to the ground state and eventually cause the red-shift emission from Mn2+.
Keywords/Search Tags:Rare Earth, Energy Transfer, Luminescent Glass, Sb3+
PDF Full Text Request
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