Vacuum-UV excitation and visible luminescence of nano-scale and micro-scale NaLnF(4):Pr3+ (Ln = Y, Lu)

Abstract

The UV-Vis luminescence of NaLnF(4):Pr3+ (Ln = Y, Lu) materials can be efficiently excited by vacuum UV radiation (VUV) such as the 172 nm emission of mercury-free Xe-discharge lamps. In this work, the optical properties of the cubic alpha-phase and the hexagonal beta-phase of NaLnF(4):Pr3+ (Ln = Y, Lu) powders are compared regarding particle sizes in the nano- and micrometer regime. Upon VUV excitation, the emission spectra of both crystal phases are found to be dominated by intraconfigurational [Xe]4f(2)-[Xe]4f(2) transitions, which is explained by the chemical properties of the ternary fluorides. Furthermore it is observed that the emission and excitation spectra of nano- and micro-scale powders are very similar, but that the luminescence intensity is affected by the average particle size. (C) 2013 Elsevier B.V. All rights reserved.