A study of Eu3+ luminescence in different phases of Na3Bi(PO4)2
In the present days, we are more dependent on electronic devices. Electronic displays with light emitting diodes (LEDs) are more common. Inorganic luminescent materials, also known as phosphors, play a vital role in LEDs and various display devices. Luminescence is a phenomenon that involves general laws of absorption and emission of radiation. Phosphors contain a host lattice in which the activator ions that are responsible for light absorption and emission are incorporated. Rare-earth ions are preferred as activators over transition metal ions due to their sharp emission transitions. The emission transitions of rare-earth ions especially that of Eu3+ depend on their chemical environment. The emission colours can be tuned by changing the host lattices. Among the host lattices, phosphate-based compounds are gaining interest due to their large band gap, outstanding chemical or thermal stability and easy preparation. The present work involves the study of Eu3+ luminescence in Na3Bi(PO4)2 which exhibits 4 different phase transitions. It will exhibit phase-α at 500°C, phase-β at 700°C, phase-γ at 850°C and phase-γ’ at 950°C. Above 1025°C it will melt. The main objective of this study is to understand the Eu3+ luminescence in different phases of Na3Bi(PO4)2 and the influence of change in the local symmetry on Eu3+ emission characteristics.
Keywords: 1. Luminescence 2. Photoluminescence 3. Phase transition 4. Structural probe