Wide Range X-Ray to Infrared Photon Detection and Energy Storage in LiTaO₃:Bi³⁺,Dy³⁺ Perovskite

Abstract

It is challenging to obtain a material that can detect photons ranging from X-rays to infrared light. Such materials have promising use to develop advanced applications like in information storage, anticounterfeiting, or X-ray imaging. This article reports on such a material; LiTaO₃:xBi³⁺,yDy³⁺ perovskite phosphor. Experimental spectroscopy, thermoluminescence, and vacuum referred binding energy diagram (VRBE) construction are combined to study the trapping processes of charge carriers. The VRBEs in the ground or excited states of Bi³⁺ and Bi²⁺ are discussed. Bi³⁺ emerges to act as a ≈1.3 eV deep hole capturing center and it may possibly also act as a 0.80 ± 0.5 eV deep electron trapping center. A linear relation between the amount of stored charge carriers and a photochromic phenomenon both induced by X-rays or 254 nm UV-light charging appears. The stored charge carriers in LiTaO₃:xBi³⁺,yDy³⁺ are removed by heating or with an optically stimulated process with 365 nm UV light to 850 nm infrared laser. More than 3 or 40 h of Bi³⁺ and Dy³⁺ based white afterglow is measurable in LiTaO₃:0.005Bi³⁺,0.004Dy³⁺ after exposure to X-rays or 254 nm UV light. Proof-of-concept light detection applications like 2D information storage and anticounterfeiting or X-ray imaging are demonstrated by using the phtotochromic and white afterglow LiTaO₃:xBi³⁺,yDy³⁺ phosphors.