| Zinc oxide plays an important role in photoelectric field because of its wide band gap and high exciton binding energy. Meanwhile, glass ceramics have great potential applications owing to possess good thermal stability, chemical stability and process-ability. This thesis introduced preparation and optical performances of ZnO nanocrystal doped zinc-aluminosilicate glass. One point is to realize spontaneous nucleation of ZnO nanocrystal in zinc-aluminosilicate system. The other point is to obtain transparent glass ceramic with excellent luminescent properties through doping rare earth ion and exploring luminescent mechanisms in ZnO nanocrystal and rare earth ions co-doped zinc-aluminosilicate glass.Based on the comprehensive review about related researches, zinc-aluminosilicate glass, ZnO nanocrystal doped zinc-aluminosilicate glass, rare earth ion doped zinc-aluminosilicate glass and ZnO nanocrystal and rare earth ion co-doped zinc-aluminosilicate glass were prepared by melting-annealing/quenching/thermal treatment method. The micro-structure, optical properties were measured by X-ray diffraction method, transmission electron microscopy, differential thermal analysis and fluorescent spectroscopy and so on. The details were listed as following:(1) ZnO nanocrystal doped zinc-aluminosilicate glass could form in a certain content range of (43.5-33.5)SiO2,(25-35)ZnO,16.1Al2O3, and15.4K2O (wt%). The effects of various amounts of ZnO, alkaline metal oxide, and alkaline earth metal oxide on formation and crystallization of zinc-aluminosilicate glass were investigated. The results indicated that zinc oxide nanocrystal only formed in the samples content K2O. Moreover, zinc oxide nanocrystal formed in the samples with SiO2/Al2O3ratio in the range of～2to～2.4. Phase separation appeared during the melting process when there was excessive content of ZnO.(2) Transparent zinc-aluminosilicate glasses with38.5SiO2,30ZnO, I6.1Al2O3,15.4K2O (wt%) were fabricated by melting-annealing method with appropriate heat treatment temperature. The effects of thermal treatment temperature and time on the crystallization behavior and optical properties of zinc-aluminosilicate glasses were investigated. The results showed that the ZnO nanocrystals formed in amorphous glass matrix at700℃. Increasing the temperature or extending heat treatment time increases the size of the ZnO nanocrystal. Meanwhile, the photo luminescence properties of the zinc-aluminosilicate glass as a function of ZnO crystal size were studied. The results shows that quantum size effects (peak shifting) akin ZnO nanocrystals size. Moreover, the thermal treatment process affected the emission peak position. The photoluminescence peak position red shifted and the ZnO nanocrystal size increased from4nm to9.8nm when the heat treatment time extended from30min to24hours.(3) Eu2O3doped zinc-aluminosilicate glasses and ZnO nanocrystalline and Eu2O3co-doped zinc-aluminosilicate glass with the composition of (35.8SiO2-15.2Al2O3-14K2O-35ZnO):xEu2O3(x=0.1,0.2,0.5, wt%) were prepared by melting-annealing method. The results reveal that Eu3+ions enter into the glass structure rather than exist in glass network in the form of Eu3+. Besides some Eu3+ions substituted at Zn2+sites and impurity level formed in the conduction band of ZnO. The intensity of emission peak due to ZnO defect increases with the increasing heat temperature or content of Eu2O3. Moreover, heat treated Eu-ions doped zinc-aluminosilicate sample shows a broad emission peak containing five emission peaks due to the intra-4f transition of Eu3+ions at394nm excitation. The results show that some electrons of ZnO transferred from valance bands to conduction bands and holes with positive electric charge is created in valance band. Some of the exited electrons transfer to substituted Eu3+(EuznO) and Zni related defects energy level and emit light. Other part of electron transfer to5Dj energy level of Eu3+ions and result in the5Do-7F1,5D0-7F2, and5D0-7F3emissions.(4) Er2O3doped zinc-aluminosilicate glasses with the composition of (33SiO2-14Al2O3-13K2O-40ZnO):xEr2O3(x=0.1,0.2,0.5, wt%) were prepared by melting, annealing and subsequent heat treatment method in air. The results show that hexagonal ZnO nanocrystals with the diameter of2-3nm formed in the quenched sample, which can influence the optical properties of glass. When the glass is heat-treated, some ZnO crystals aggregate together and non-radiative centers form. The results show that the emission peak position shifted to lower energy and its intensity decreases with increasing the heat treatment temperature or extending the heat treatment time. Furthermore, indirect excitation of Er-ions by ZnO nanocrystal in Er2O3doped zinc-aluminosilicate glasses studied. The results show that Er ions is indirectly excited by the ZnO nanocrystal resulted emission, indicating energy transfer between ZnO nanocrystal and Er3+ions. While there is no energy transfer occurs between ZnO defects and Er ions. However, energy transfer generated when electron hole pairs coming from ZnO nanocrystal transfer between the Er3+ion and the ZnO nanocrystal at394nm excitation of the indirect excitation of Er3+ion. |
PDF Full Text Request