Lanthanide spectroscopy in probing structure-property correlation in multi-site photoluminescent phosphors

Lanthanide luminescence gains significant attention during the last decade or so because of its unique optical properties. In designing a phosphor material various parameter needs to be optimized as far as lanthanide doped materials are concerned, such as host-dopant energy transfer, the local structure of lanthanide ion, point group symmetry of lanthanide ion, etc. In this context, we have explored a variety of novel oxide hosts for lanthanide based luminescent materials. In this review, we have explored the optical properties of various lanthanide ions doped in multiple sites host such as Sr2SiO4, Sr2CeO4, SrZrO3, Zn2P2O7, Gd2Zr2O7, Nd2Zr2O7 etc. and correlate the results with the one reported in literature. The focus was on establishing structure-property correlation, identifying the dopant local site, understanding the dynamics of host to depend energy transfer, defect related emission etc., which are especially important for designing tunable phosphors for optoelectronic devices. Europium ion was used as a spectroscopic probe to decipher its point group symmetry and correlate it with the structure of the host materials. Defects are not always deleterious and can sometime leads to interesting optical properties and few nano and bulk materials were synthesized wherein visible blue-green emission could be seen due to the presence of oxygen vacancies and other defects. (C) 2020 Elsevier B.V. All rights reserved.