Research On Luminescence Of Nanoporous Glass Composite Materials

The ion-doped luminescent glass and glass-ceramics have been the focus of research for optical functional materials. The quartz glass, as an host for rare earth ions doping, shows extremely serious concentration quenching effect due to the forming of rare earth ion clusters. While for the traditional glass-ceramic, it is difficult to control the species, size and distribution of nanocrystals. Since the connected uniform channel in nanoporous glass provides a well-established microenvironment for accommodating dopant ions and the crystal growth, nanoporous glass offers an efficient approach to solve the above technical problems.In this work, the undamaged nanoporous glass with connected pores is prepared based on the traditional melt phase-separation method, and the pores are well controlled and uniformly distributed. The yield of nanoporous glass is as high as 90%. The investigation shows that the sintered nanoporous glass has a high transmittance in ultraviolet region.Using this nanoporous glass as a substrate, the Eu²⁺/ Al³⁺, Eu²⁺/ Mn²⁺ and Eu²⁺/Mn²⁺/Al³⁺ co-doped luminescent high silica glass is prepared by ions-impregnation and high temperature sintering. The emission intensity of Eu²⁺ and Mn²⁺ is enhanced by co-doping Eu²⁺/ Al³⁺ respectively. The emission color could shift from blue to green by changing the concentration of Eu²⁺ and Al³⁺. The energy transfer between Eu²⁺ and Mn²⁺ is also observed in this Eu²⁺/Mn²⁺/Al³⁺ co-doped high silica glass.On the basis of as-prepared nanoporous glass, a new method to prepare glass- ceramics is presented. Colorless transparent high silica glass with nano-crystal is prepared by a two-segment process, which involves crystal growth at low temperature and nanochannel collapse at high-temperature. With this approach, high silica glass with nano-crystallineβ-Ga₂O₃ and ZrO₂ semiconductor could be obtained. Emission of UV, blue, green and red light in high silica glass ceramics with nano-crystallineβ-Ga₂O₃ is presented. In the high silica glass ceramics with nano ZrO₂, violet and blue-green light emission is observed. Additionally, it is found that the Zr4+ion could enhance the luminescence of the high silica glass matrix at 288 nm and 396 nm. This new preparation method overcomes the shortcomings of difficulty in controlling the crystal species, crystal size and its luminescence in the porcess of preparing the traditional glass-ceramics.