Study On The Enhancement Of The Luminescence Properties And Mechanism Of The Rare Earth Ion Doped Silicate Glass By Adjusting The Presence Of Silver Based On The Ion Exchange Method

Rare earth ions doped luminescent glasses,as one of the important optoelectronic materials,have been considerably investigated and applied in the laser,optical illumination,energy storage,and communication devices due to their high transparent,easy processing properties and recyclability.However,the intrinsic small emission and absorption section of rare earth ions lead to their weak luminescence efficiency,which limit their practical application.Recently,the noble metals such as Au,Ag and Cu were introduced into the rare earth ions doped glasses to improve their photoluminescence.Compared with the other noble metals,the noble silver has abundant existing states such as Ag⁺,Ag⁺-Ag⁺pairs,molecule-like?ML?Ag nano-clusters and Ag nanoparticles,which could be used to enhance the photoluminescence of rare earth ions because thier excellent luminescence property.The various silver existing states co-existed in the rare earth doped glasses,thus the specific contribution of different Ag states to the luminescence enhancement of rare earth ions are not clear in the rare earth doped glasses,which has seriously impeded their potential applications.Therefore,the selective preparation of silver existing state in the rare earth ions doped glasses is necessary to obtain the correlation between silver existing states and luminescence enhancement of rare earth ions doped glasses.First,ultra-small molecule-like Ag?ML-Ag?nanoclusters were prepared by the Ag⁺-Na⁺ion-exchange process in aluminosilicate glass.The influence of ion-exchange temperature,ion-exchange time and ratio of molten salt composition on the formation of ML-Ag nano-clusters was investigated systematically in the aluminosilicate glass.The results demonstrated that the stabilized ML-Ag nano-clusters with the size of 1–3 nm were formed by controlling the ion-exchange parameters.In addition,the influence of Eu³⁺doping on the formation of ML-Ag nano-clusters was observed in the silicate glass,promoting the growth of ML-Ag nanoclusters.The luminescence enhancement of Eu³⁺was obtained due to efficient energy transfer from ML-Ag nano-clusters to Eu³⁺.Then the selective preparation of a single silver state was successfully achieved in Sm³⁺doped borosilicate glass.The results demonstrate the isolated Ag⁺ions exist in the Sm³⁺borosilicate glass when the ratio of AgNO₃/NaNO₃ in the molten salt is1/1000.The Ag nano-clusters were formed in the Sm³⁺borosilicate glass when the AgNO₃/NaNO₃ ratio is 1/10.The influences of Ag⁺ions or Ag nano-clusters on the photoluminescence of Sm³⁺were systematically investigated.The results show that the photoluminescence of Sm³⁺was enhanced by the Ag⁺ions or Ag nano-clusters,which was attributed to the energy transfer from Ag⁺ions or Ag nano-clusters to Sm³⁺,respectively.Finally,the influence of the glass component on the state of silver in the glass after ion exchange was investigated.The blue luminescence at the 410 nm from the Ge²⁺was observed.The SiO₂ addition promoted the formation of Ge²⁺,which is because the Si⁴⁺ions can deprive the O^2-ions from the Ge⁴⁺ions caused by the lower optical basicity of Si⁴⁺ions than Ge⁴⁺ions.The results showed GeO₂ could promote the growth of Ag nano-clusters,and SiO₂ could stabilize the size distribution and lead to the miniaturization of Ag nano-clusters.The tunable photoluminescence of Ag nano-clusters was obtained by controlling the size of Ag nano-clusters.It is noticed that the Ag nano-clusters formed in the germanate glass without the rare earth ions showed the white light emission characteristic excited at the blue chip.