# First-principles LDA+U calculations and luminescence study of YNbO4

Lim, Thong Leng and Low, Lay Chen and Nazarov, Mihail and Yoon, Tiem Leong and Ahmad Fauzi, M. N. (2014) First-principles LDA+U calculations and luminescence study of YNbO4. Physica Scripta, 89 (9). ISSN 1402-4896

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Official URL: http://iopscience.iop.org/1402-4896/89/9/095102

## Abstract

Yttrium niobate (${\rm YNb}{{{\rm O}}_{4}}$) phosphor is studied experimentally and through first-principles calculations, in which the structural and electronic properties of ${\rm YNb}{{{\rm O}}_{4}}$ are investigated using the local-density approximation LDA+U method. The absorption and luminescence experiments that were conducted on the host lattice show the band gap to be $\approx$ 4.1 eV. The LDA+U calculations allow us to obtain a band gap of 4.28 eV. The density of states obtained from the calculation shows that O 2p states contribute to the valence band. The lower conduction band is mainly composed of Nb 4d states, while the upper conduction bands involve contribution mainly from Y 4d states. The partial DOS of each atom in the niobate system is then compared to the ultraviolet (UV) and vacuum ultraviolet (VUV) spectra from A photoluminescence excitation (PLE) experiment to explain the nature of the bands observed.

Item Type: Article T Technology > TA Engineering (General). Civil engineering (General) Faculty of Engineering and Technology (FET) Ms Nurul Iqtiani Ahmad 25 Sep 2014 03:30 21 Nov 2014 01:41 http://shdl.mmu.edu.my/id/eprint/5753