Reversible up-conversion luminescence modulation based on UV-VIS light-controlled photochromism in Er3+ doped Sr2SnO4

Abstract

Up-conversion phosphors with reversible luminescence modulation in response to external stimuli have great potential for applications in optical memory devices, photoswitches and optical sensing. For the accessibility and the controlling convenience, light stimulation is an optimal method to realize the modulation. Here, we report a novel phosphor Sr₂SnO₄:Er³⁺, which shows both up-conversion luminescence and reversible photochromic properties upon introducing Er³⁺ ions into the Sr₂SnO₄ host. The up-conversion luminescence can be reversibly modulated by alternating ultraviolet light (270–310 nm) and visible light (440–520 nm) irradiation based on the reversible photochromic reaction. 290 and 460 nm are found to be the most efficient wavelengths to control the photochromic reaction and luminescence modulation. And the photochromic degree and luminescence modulation ratio are dependent on the doped Er³⁺ ion concentration. Large luminescence decrease (84.9%) and increase ratios (266.0%) are achieved in Sr₂SnO₄:0.005Er³⁺. Furthermore, the mechanisms of photochromism and luminescence modulation are investigated.