Optical properties of SrAl2−Si O4−N :Eu2+, Dy3+ phosphors for AC-LEDs

Series of green emitting SrAl2−xSixO4−xNx:Eu2+, Dy3+ phosphors have been synthesized via a high temperature solid-state method. The effects of (SiN)+ on phase structural, emission and excitation spectra and decay curves were investigated systematically. The X-ray diffraction (XRD) patterns show that the maximum amount of solubility is about x = 0.10. The emission wavelength can be red-shifted from 509 to 515 nm with increasing (SiN)+ concentration. Meanwhile, the average lifetime of samples are shortened from 845.86 to 765.34 ms, which can appropriately compensate for the AC time gap and the emission color of AC-LEDs will be improved. Finally, we use these phosphors and near UV-chips to fabricate LEDs, which show more stable luminescence properties accompanying with the decrease of the luminous efficiency as the (SiN)+ content increases.