Abstract
As a new type of light source in twenty-first Century, energy saving and environmental protection, long use time, and high luminous efficiency are the advantages of white LED compared with the traditional incandescent lamp and fluorescent lamp. Through the combination of UV / near UV LED chip and three colour phosphors (blue, green and red) is the main way to realize white light LED. Therefore, all parts of the world study and breakthrough related technologies. In this paper, by high temperature solid phase reaction method, several white LEDphosphors that can be excited by UVare prepared, and the luminescence properties, thermal stability, concentration quenching and the mechanism are profoundly studied. The main results are as follows:Na3YSi2O7: Sm3+ fluorescent powder for white light LED is prepared by high temperature solid phase method. Carry out X- ray diffraction analysis and UV Vis diffuse reflex spectra, excitation spectra, emission spectra, temperature dependent fluorescence spectroscopy and so on characteristics. Under the near ultraviolet (404 nm) excitation, Na3YSi2O7: Sm3+ emits orange light. In the emission spectrum, it presents the characteristic peak of Sm3+, namely4G5/2-6H5/2 (564 nm), 4G5/2-6H7/2 (583 nm), 4G5/2-6H7/2 (609 nm) and 4G5/2 -6H9/2 (651 nm). In Na3YSi2O7 matrix, the critical quenching concentration of Sm3+ is 3 mol%, and the concentration quenching mechanism is the electric dipole-electric dipole interaction function. The CIE coordinates of Na3YSi2O7: Sm3+ phosphor are calculated, (0.5449, 0.4472), and the activation energy of thermal quenching is 0.22 e V. The results show that Na3YSi2O7: Sm3+ phosphor can be used for white LED.
