Crystal growth and upconversion luminescent properties of KLu2F7:Yb,Er nanocrystals

Abstract Crystal growth of KLu 2 F 7 nanocrystals is investigated by dosage- and time-dependent analysis. XRD patterns reveal the phase transition along with the dosage of fluorine source and reaction times, where the cubic-phase KLu 3 F 10 turns into orthorhombic KLu 2 F 7 . TEM images show that the dimensions of as-prepared samples are below a hundred nanometers, with different shapes from hexagonal plate to hexagonal rod. The upconversion properties of the as-prepared samples are investigated. It is found that the upconversion emission is lowered as the shape of the samples varies. Moreover, the orthorhombic KLu 2 F 7 :Yb,Er nanocrystals present more enormous upconversion luminescence than the cubic counterparts. In a word, the orthorhombic nanocrystals are found to be good candidate for upconversion luminescence and of great importance for potential applications in solar cells, multicolor display and bioimaging.