Upconversion Luminescence Investigations of Rare Earth Doped NaYF4 Nanocomposites

Abstract

The upconversion (UC) luminescence material produces one high-energy photon when two photons are sequentially absorbed. These higher energy photons can be used for the sensing, newlinesolid display technique, photo catalysis and temperature sensor technology, active medium for newlineUC lasers, bioimaging, light emitting diodes and photovoltaic in solar cell applications. newlineTherefore, an ideal host structure should have high transparency for near infrared photons in the newlinecrystal, low phonon energy and high chemical and thermal stability to avoid variations in the newlinecrystal lattice. It is notable that rare earth ions (particularly Er3+ and Yb3+) show most efficient newlineUC process. Moreover, the host materials should have high tolerance to dopant ions for newlineachieving high doping profiles. By utilizing UC process, long wavelength infrared photons newlinepresent in the solar spectrum can converted into shorter wavelength visible photons. One way to newlinedeal with the increment in the luminescence efficiency of nanoparticles is the utilization of coreshell newlinestructure where a thin-shell of material with comparative lattice constants is developed newlinearound the luminescent nanoparticles. Secondly, the core-shell nanoparticles can also be joined newlinewith Ag/Au nanocrystals. In a recent study, it is observed that the UC luminescence intensity of AgatSiO2atNaYF4: Yb3+, Er3+ core-shell nanoparticles was 14.4 times higher than SiO2atNaYF4: Yb3+/Er3+ core-shell nanocomposites. newline