Photoluminescence properties of a novel red-emitting phosphor Eu 3+ activated scandium molybdate for white light emitting diodes

Abstract A series of red-emitting phosphors of Sc 2 (MoO 4 ) 3 : x%Eu 3+ have been successfully synthesized at 800 °C by solid-state reaction. X-ray diffraction, scanning electron microscopy, photoluminescence spectra and decay curves were used to characterize the structures and luminescence properties. In the excitation spectrum, the strongest absorptions of 7 F 0 ⿿ 5 L 6 and 7 F 0 ⿿ 5 D 2 match well with the emission wavelength of the near-ultraviolet InGaN and blue GaN chips. The CIE value of Sc 2 (MoO 4 ) 3 : 40%Eu 3+ sample reaches (0.665, 0.334), which is very close to the NTSC standard (0.67, 0.33), demonstrating the highly pure red lights emitted. The decay curves of Eu 3+ : 5 D 0 ⿿ 7 F 2 emission exhibit a bi-exponential function excited by a 266 nm nanosecond-pulsed laser resulting from the lattice distortion which can speed up electric dipole transition. The good excitation profile and pure red emission indicate Sc 2 (MoO 4 ) 3 : Eu 3+ is a promising red-emitting phosphor for its application in commercial white light emitting diodes.