Tailoring the Luminescence Intensity of 808 nm responsive Core-shell Upconversion Material through Lattice Defect

Abstract

Lanthanide-doped inorganic nanocrystals are able conversion of NIR light to visible or even to ultraviolet through the upconversion process. In recent times, 980 nm-responsive NIR-upconverting crystalline nanoparticles have been used extensively in biological applications. However, due to the strong water absorption profile of 980 nm excitation, the concerned upconverting nanoparticle (UCNP) suffers from a heating effect and poorer tissue penetration. Although a type of 808 nmresponsive core-shell-based UCNP has been proposed to overcome the above problem, such nanoparticles lack the diversity and intensity of the upconverted UV-visible emission required to perform any effective biological application. Herein, the proposed plan, a pathway for developing 808 nm-responsive core-shell UCNP with an intense emission profile is described. In the beginning, the reason and challenges for developing such a particular type of UCNP is discussed. Subsequently, a rational methodology to fabricate core-shell-based UCNP with a well-thought-out crystal engineering approach will be discussed also. Apart from synthesizing the UCNP with an enhanced emission profile by incorporating non-lanthanide doping of Li+ in the core nominally, a thorough characterization of the crystalline structure and photoluminescence study is proposed. The detailed mechanism behind the intensification of the emission profile is to perturbation of crystal field symmetry of crystal lattice to be investigated by lattice strain analysis, phase purity was also confirmed by Rietveld refinement by using high energy Synchrotron X-ray radiation