UV-vis induced emission-color switching in Eu-doped BaNa2MgP2O8

This paper demonstrates emission-color change of BaNa2MgP2O8: Eu through photoredox reactions of dopant europium ions. Europium doped BaNa2MgP2O8 was prepared by high-temperature solid state reaction in air. Under UV excitation, Eu-doped BaNa2MgP2O8 exhibited weak mixed-color emission involving orange and blue components. They were derived from 4 f(6)-4 f(6) intraconfigurational electron transition in Eu3+ and 4 f(6)5d(1)-4 f(7) interconfigurational electron transition in Eu2+, respectively. Since Eu3+ reversible arrow Eu2+ photoredox reactions were both facilitated by UV-vis photostimulation, Eu3+/Eu2+ ratio approached to an equilibrium value depending on the stimulation wavelength. The resultant emission color was continuously varied by stimulation light. Optical absorption character and ESR spectroscopy revealed that the photoredox reactions in Eu were caused by electron transfer between Eu and PO43- within BaNa2MgP2O8. (c) 2022 Elsevier B.V. All rights reserved.