Photoluminescence properties of a novel red-emitting phosphor Eu3+ activated scandium molybdate for white light emitting diodes

• Red-emitting phosphors of Sc2(MoO4)3:Eu3+ have been synthesized and investigated.
• Phosphors can be effectively excited by near-ultraviolet InGaN and blue GaN chips.
• The CIE value of Sc2(MoO4)3:Eu3+ reaches (0.665, 0.334) closer to NTSC standard.

A series of red-emitting phosphors of Sc2(MoO4)3: x%Eu3+ 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 7F0 → 5L6 and 7F0 → 5D2 match well with the emission wavelength of the near-ultraviolet InGaN and blue GaN chips. The CIE value of Sc2(MoO4)3: 40%Eu3+ 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 Eu3+: 5D0 → 7F2 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 Sc2(MoO4)3: Eu3+ is a promising red-emitting phosphor for its application in commercial white light emitting diodes.

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