Anomalous Fluorescence Thermal Quenching in a Red-emitting RbZnF3:Eu ³⁺ Phosphor under Violet Excitation

Thermal quenching is a key challenge in the application of fluorescent materials in solid state lighting devices.Herein, we report a perovskite phosphor RbZnF3:Eu 3+ exhibiting anti-thermal quenching behavior.Under violet excitation, this phosphor yields bright red emission.As the temperature rises, the luminescence intensity first increases up to 175 (i.e., anti-thermal quenching) and then decreases.When the temperature is above 200 , the luminescence intensity falls below the value at room temperature.We carry out comprehensive characterizations and propose that the observed anti-thermal quenching behavior is mainly due to the existence of defect levels.First-principles calculations show that Rb vacancy and F vacancy could be responsible for the observed defect levels.We also fabricate a white LED using the RbZnF3:Eu 3+ phosphor to verify its potential application.