Effects Of Rare Earth On Luminescence Property Of Silver Borate Glasses Applied In White Light Emitting Diodes

Recently,lanthanide ions doped luminescent materials are of significant interest because of their extensive application in lighting,laser and display.As a novel green lighting source,the fourth generation white light emitting diodes?W-LED?not only improve illuminating quality but also improve lighting efficiency.Therefore,lanthanide ions doped luminescent materials are widely investigated by scientific researchers.In order to achieve white light emitting by using glass phosphors,a series of Sm³⁺,Eu³⁺,Nd³⁺,Y³⁺ doped silver borate glasses with same silver contents were prepared via a melt-quenching technique.A combination of red-orange light emission produced by rare earth ions and blue-green light emission produced by Ag aggregation was used to obtain white light emission.More details can be described as follows:?1?Sm³⁺,Eu³⁺ single doped silver borate glasses were prepared via a melt-quenching technique,the absorption spectra and the fluorescence spectra of the samples with various Sm³⁺,Eu³⁺ concentrations were measured,blue-green light emission of Ag aggregates and the red-orange light emission of Sm³⁺ or Eu³⁺ were observed.From a series of samples,the sample with strongest luminescence was chosen to measure the excitation and emission spectra.The shift of the excitation and emission peaks with excitation and minitoring wavelengths can be seen,which indicates the existence of different Ag aggregates states.The results of color coordinates and color temperature indicates that the samples present strong luminous intensity and give out the warm white light.This material has a potential commercial value in the field of WLED.?2?Nd³⁺ doped silver borate glasses were prepared via the same technique,the absorption spectra and the fluorescence spectra of these samples were measured under the same experimental conditions,Ag aggregates states were observed.The excitation and emission spectra of the sample exhibiting stronger emission intensity were measured,it is observed that the excitation and emission peaks shift with changing excitation and minitoring wavelengths.The color coordinates and color temperature of these samples indicated that the samples cold white light and high luminescent intensity.The experimental results are meaningful for the research of WLED.?3?A series of different Y³⁺ concentration doped silver borate glasses were prepared by the same synthesis method.The absorption spectra was measured and the emission spectra was also measured with the excitation wavelength 465 nm.In the spectra,Ag aggregates states were observed.By comparison,Sm³⁺,Eu³⁺,Nd³⁺ with 4f energy level and Y³⁺ without 4f energy level,the emission spectra of lanthanide ions doped samples were normalized,and the results shows lanthanide ions have no effect on he form and distribution of Ag aggregates states.However the lanthanide ions doping concentration in samples would cause the change of crystal field,which changes the transition rate of Ag aggregates in samples.