Study On Luminescence Properties Of (PDMS+PTMO)/SiO2 Hybrid Materials Incorporated With Rare Earth

The rare earth complex emits characteristic fluorescence of rare earth ions through the excitation of organic ligands and energy transmission to the rare earth ions. Its monochromaticity is good. But rare earth organic complex is not thermostable, so this fatal disadvantage limits its usable range. The organic/inorganic hybrid materials have high thermal and chemical stability. Therefore, we can synthesize the rare earth organic complex in organic/inorganic hybrid material in order to improve the luminescence properties of the rare earth organic complex. The rare earth doped organic/inorganic hybrid materials not only have the advantages of both organic and inorganic materials, but also have good luminescence properties In the first part of experiment, Eu³⁺,La³⁺-PABA-phen rare earth complex were successfully synthesized by coprecipitation. The samples were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Fluorescence Spectra (FS).Infrared spectrum analysis showed that the rare earth complex had been successfully synthesized. Fluorescence spectrometric analysis indicated that rare earth complex presented the characteristic emission spectrum of Eu³⁺..In the second part of experiment, homogeneous and transparent (PTMO+PDMS)/SiO₂ organic-inorganic hybrid material was successfully synthesized with HO-terminated PDMS,PTMO and TEOS by the acid catalyzed sol-gel process. The hybrid material was characterized by FTIR, UV-VIS, SEM and other analysis methods. The results indicate that the organic phase and inorganic phase of the hybrid material are linked by chemical bond and disperse perfectly. Meanwhile, the materials have a excellent optical transparency.In the last part of experiment, A series of rare earth doped (PDMS+PTMO)/SiO₂ hybrid materials were in-situ synthesized by sol-gel method. The effects of the La³⁺,organic phase(PDMS and PTMO) and process parameters(pH of the HCl and sintering temperature) on luminescence properties of the (PDMS+PTMO)/SiO₂ hybrid materials were studied. The FTIR analysis showed that Eu³⁺,La³⁺ rare earth complex had been successgully in-situ synthesized in doped (PDMS+PTMO)/SiO₂ hybrid materials. The FS analysis showed that Eu³⁺,La³⁺-rare earth doped PDMS/SiO₂ hybrid material not only presented the characteristic emission spectrum of Eu³⁺ but also presented the two emission peaks of PDMS. La³⁺ had not fluorescence enhancement on Eu³⁺ in the rare earth doped (PDMS+PTMO)/SiO₂ hybrid materials. The incorporation of organic phase(PDMS and PTMO) within a certain range could increase the fluorescence intensity of the (PDMS+PTMO)/SiO₂ hybrid materials. Especially, the more the amount of PTMO was, the higher the intensity of the emission peak of rare earth doped (PDMS+PTMO)/SiO₂ hybrid luminescence materials at 343nm was.This is because of the emission of PTMO. When the pH of the catalyst was in a certain range(≤3.0), the higher the the pH of the catalyst was, the higher the intensity of the emission peak of Eu³⁺ in rare earth doped (PDMS+PTMO)/SiO₂ hybrid luminescence materials was. But this is opposite to the the intensity of the emission peak of matrix in hybrid luminescence materials. When the sintering temperature was in a certain range(150℃≤T≤350℃), the higher the sintering temperature was, the lower the intensity of the emission peak of matrix in hybrid luminescence materials was. But the the intensity of the emission peak of Eu³⁺ ascended at first. Then it went down . It is supposed that the material which hinder the luminescence decomposed at high temperature.