Synthesis and Characterization of Upconversion nanophosphors for Biophotonics Applications

Infrared light based detection and therapy is well known in the medical industry. In this project, we are proposing the development of nanoparticle based infrared upconversion technology for various biophotonics applications such as imaging and therapy with our infrared window of interest range from 800-980nm. Various upconversion phosphors such as M₂O₂S (M=La, Gd, and Y), NaYF₄ have been doped with infrared active rare earth ions such as Yb: Er, Yb: Ho etc. to get visible emission in the red and green. Synthesis conditions have been optimized for getting the brightest phosphor in the size range of 100-200 nm. Various optical characterizations have been done to explore the excitation, emission mechanisms and the luminance efficiency. Properly optimized phosphors are then surface functionalized with suitable biomolecules for in vitro and in vivo applications such as photodynamic therapy and bio imaging .