Luminescence investigations of hydrothermally synthesized terbium doped zirconium tungstate nanorods

Abstract

Rare-earth based phosphors play a key role in enhancing the quality of the phosphor converted LEDs (pc-LEDs). But the creation of phosphors with high thermal stability is still a task. This work aims to investigate the luminescence properties of ZrW2O8, which is known to have a negative or almost zero coefficient of thermal expansion. ZrW2O8 doped with Tb3+ is optimized by the conventional hydrothermal method in acidic medium. The PXRD analysis confirms the crystallization of the material into high purity cubic phase to the P213 space group. The tungstate group's distinctive vibrational modes were identified by FTIR analysis. TGA analysis demonstrates the remarkable thermal stability of the material over a wide temperature range. The preferential growth along one direction to form distinct nanorods was investigated using TEM. The optical band gap is found to increase after doping. The high and broad charge transfer band at 284 nm in the excitation spectra is an indication of the efficient energy transfer from the host to Tb3+ ions and the possibility of NUV excitation. The characteristic green emission peak of the Tb3+ at 543 nm and the values of the CCT and CP obtained using the colorimetry study suggest that the obtained material can be used as a green component to produce cold white LEDs.