Upconversion Luminescence Reversible Modulation of Photochromic Ba2YTaO6 Double Perovskite Phosphors Toward Anticounterfeiting Application

Abstract Double perovskite (DP) phosphors attract extensive attention due to their potential applications in the field of optoelectronics. Photochromism‐induced luminescence modulation can extend their application fields. However, designing and preparing DP phosphors with expected photochromic and luminescent properties is still challenging. Herein, the photochromic Ba 2 YTaO 6 : Yb 3+ , Er 3+ , Co 2+ DP with upconversion luminescence properties is developed. The color of the sample turns from white to pink upon 254 nm UV light irradiation, which is fast fading upon 473 nm laser illumination. The mechanism of photochromism is related to the formation of color centers, and the doping of Co 2+ ions is crucial for the improvement of photochromism, which is from the increasing of traps depth, the oxygen vacancies, and the carrier concentration of the matrix caused by Co 2+ doping. The upconversion luminescence of Er 3+ ions can be reversibly modulated by the photochromic effect, exhibiting excellent reproducibility and high stability. The potential application of photochromic Ba 2 YTaO 6 : Yb 3+ , Er 3+ , Co 2+ phosphor is demonstrated in the field of anticounterfeiting and three‐dimensional (3D) artwork. This work not only offers insight into the photochromic mechanism of DP but also presents guidance for developing other photochromic DP phosphors.