Near-ultraviolet excitation-based bluish-green emitting K2ZnSiO4: Eu2+ nanophosphors for white light-emitting applications

Abstract

The K2ZnSiO4: Eu2+ nanophosphor materials were synthesized via a sol-gel method. The morphology of the synthesized materials was examined by field-emission scanning electron microscope images. The structural properties were analyzed from X-ray diffraction (XRD) pattern and Fourier transform infrared spectrum. The K2ZnSiO4 host lattice crystallizes in a cubic phase, and the XRD pattern matches well with the standard JCPDS card values and does not show any impurity peaks. The luminescence properties were studied using the photoluminescence (PL) excitation and PL emission spectra. The broadband excitation in the near-ultraviolet (NUV) region and the broadband emission in the visible region make this phosphor material suitable for the application of NUV-based white light-emitting diodes. The thermal stability of the material was tested by calculating the activation energy value which was found to be 0.296 eV. The synthesized K2ZnSiO4: Eu2+ nanophosphor was then coated onto the NUV light-emitting diode along with a red-emitting phosphor to get visible white-light emission with a color rendering index value of 81 and a correlated color temperature value of 5730 K.