Charging storage phosphors using a white flashlight via the upconversion approach

As an emerging approach to charge storage phosphors, upconversion charging (UCC) is attracting increased attention owing to its fundamental and practical perspectives. Despite the potential, further development of the UCC technology is restricted by the limited types of excitation light sources. Here, we use a white flashlight as excitation to investigate the UCC performance of storage phosphors. We demonstrate, as an example, that a Y3Al2Ga3O12:Pr3+ phosphor exhibits long-lasting emissions in the ultraviolet and visible regions after intense illumination from the flashlight. Thermoluminescence investigations reveal that both excited-state absorption and energy-transfer upconversion are involved in the UCC process. Based on the luminescence performance of the white-light charged phosphor, a conceptual thermometry approach is introduced, which can remotely sense the local temperature by monitoring the afterglow intensity ratio. Considering the wide use of flashlight, such a white-light excitability and the associated glow emission may potentially revolutionize the way to utilize storage phosphors.