8th February 2021

Strong structural phase sensitive rare-earth photoluminescence color flips in KLaF4:RE3+ (RE3+ = Eu3+, Er3+/Yb3+) nanocrystals

Systematic and strong rare-earth photoluminescence (PL) color flips which are highly sensitive to the structural phase transformation in bio-compatible KLaF4:RE3+ (RE3+ = Eu3+, Er3+/Yb3+) nanocrystals are demonstrated. The unusual photoluminescence color change from dominant Red) to Orange in KLaF4:Eu3+ due to the site-selective occupancy and local symmetry around Eu3+ ions, according to the crystal packing transformation. The NIR excited up-conversion photoluminescence (UC-PL) of Er3+ ions produce strong color flip from green to red dominated emissions based on their cubic or hexagonal crystal packing. The presented study substantially reveals the local host effects and these two distinct polymorph nanoparticles can be potentially utilized to color-specific studies related to applications such as color-specific biological in-vitro and in-vivo imaging and other optoelectronic device applications. Published in Dalton Transactions, 2020

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Contact details:

Dr. Mohini Gupta, Rajat Bajaj, and Prof. G. Vijaya Prakash

MS-415, 3rd floor, Department of Physics, Indian Institute of Technology Delhi, Hauz khas, New Delhi, 110 016, India