Samarium doped lead-zinc-phosphate glasses having composition(60-x)P_(2)O_(5)-20PbO-20ZnO-xSm_(2)O_(3) where x=0,0.5,1.0,3.0mol%were prepared by using the melt quenching technique.The Archimedes method was used to mea...Samarium doped lead-zinc-phosphate glasses having composition(60-x)P_(2)O_(5)-20PbO-20ZnO-xSm_(2)O_(3) where x=0,0.5,1.0,3.0mol%were prepared by using the melt quenching technique.The Archimedes method was used to measure their densities,which are used to calculate the molar volumes.The values of densities lie in the range 3.698–4.090 gm/cm^(3) whereas those of molar volume lie in the range of 37.24–40.00 cm^(-3).UV-vis-NIR absorption spectroscopy in the wavelength range 200–2000 nm was carried out.Absorption spectra consist of seven absorption peaks corresponding to the transitions from the 6H5/2 ground state to various excited energy levels.The energy band gap measured from the optical absorbance is found to be in the range of 3.88–4.43 eV and 3.68–4.33 eV for direct and indirect transitions,respectively.In addition,the photoluminescence spectrum shows four prominent emission bands centered at 560,597,642 and 700 nm corresponding to the 4G5/2–6HJ(J=5/2,7/2,9/2,11/2)transitions respectively and the intensity of all the bands are enhanced as the concentration of Sm3+ions increases.展开更多
The melt quenching method is used to prepare erbium-doped silver nanoparticle(NP)embedded phosphate glass.The effect of annealing on the glass on the formation of silver NPs produced by the reduction of silver(Ag^(+)...The melt quenching method is used to prepare erbium-doped silver nanoparticle(NP)embedded phosphate glass.The effect of annealing on the glass on the formation of silver NPs produced by the reduction of silver(Ag^(+)→Ag^(o))is studied.The glass samples are characterized by x-ray diffraction,UV-vis-NIR absorption,photoluminescence spectroscopy and transmission electron microscopy(TEM)imaging.The absorption spectra reveal not only the peaks due to Er^(3+)ions,but also the surface plasmon resonance band of silver NPs located around~442 nm.The TEM imaging shows the homogeneous distribution of silver NPs of almost spherical shape with an average diameter of~5 nm.Upconversion luminescence spectra show two major emissions at 550 and 638 nm,originating from the 4S_(3/2)and 4F_(9/2)energy levels of the Er^(3+)ions,respectively.The enhancement in the luminescence intensity of both the green and red bands is found to be due to the effective local field of the silver NPs as well as the energy transfer from the nanoclusters,comprised of centers with silver ions bound to silver atoms in dimers or trimers to Er^(3+)ions,whereas quenching occurred due to the energy transfer from erbium ions to silver NPs(Er^(^(3^(+)))→Ag^(o)).展开更多
基金Supported by RMC through research grant of Q.J130000.7126.02J77/GUP and IDF UTM.J.10.01/13.14//128(201009M10001)Universiti Teknologi Malaysia.
文摘Samarium doped lead-zinc-phosphate glasses having composition(60-x)P_(2)O_(5)-20PbO-20ZnO-xSm_(2)O_(3) where x=0,0.5,1.0,3.0mol%were prepared by using the melt quenching technique.The Archimedes method was used to measure their densities,which are used to calculate the molar volumes.The values of densities lie in the range 3.698–4.090 gm/cm^(3) whereas those of molar volume lie in the range of 37.24–40.00 cm^(-3).UV-vis-NIR absorption spectroscopy in the wavelength range 200–2000 nm was carried out.Absorption spectra consist of seven absorption peaks corresponding to the transitions from the 6H5/2 ground state to various excited energy levels.The energy band gap measured from the optical absorbance is found to be in the range of 3.88–4.43 eV and 3.68–4.33 eV for direct and indirect transitions,respectively.In addition,the photoluminescence spectrum shows four prominent emission bands centered at 560,597,642 and 700 nm corresponding to the 4G5/2–6HJ(J=5/2,7/2,9/2,11/2)transitions respectively and the intensity of all the bands are enhanced as the concentration of Sm3+ions increases.
基金Supported by RMC,UTM and MOHE through the research grant VOTE 06J33,06J39 and IDF UTM.J.10.01/13.14//128(201009M10001).
文摘The melt quenching method is used to prepare erbium-doped silver nanoparticle(NP)embedded phosphate glass.The effect of annealing on the glass on the formation of silver NPs produced by the reduction of silver(Ag^(+)→Ag^(o))is studied.The glass samples are characterized by x-ray diffraction,UV-vis-NIR absorption,photoluminescence spectroscopy and transmission electron microscopy(TEM)imaging.The absorption spectra reveal not only the peaks due to Er^(3+)ions,but also the surface plasmon resonance band of silver NPs located around~442 nm.The TEM imaging shows the homogeneous distribution of silver NPs of almost spherical shape with an average diameter of~5 nm.Upconversion luminescence spectra show two major emissions at 550 and 638 nm,originating from the 4S_(3/2)and 4F_(9/2)energy levels of the Er^(3+)ions,respectively.The enhancement in the luminescence intensity of both the green and red bands is found to be due to the effective local field of the silver NPs as well as the energy transfer from the nanoclusters,comprised of centers with silver ions bound to silver atoms in dimers or trimers to Er^(3+)ions,whereas quenching occurred due to the energy transfer from erbium ions to silver NPs(Er^(^(3^(+)))→Ag^(o)).
