Multimode luminescence relates to how charge carriers are transported and recombined in response to various physical excitations. It shows promising applications in many fields like advanced anti-counterfeiting, information storage and encryption. Enabling a stable single compound with multimode luminescence is a unique technology but still remains a challenge. Herein, a versatile and high-performance energy storage LiTaO₃:0.01Tb³⁺,xGd³⁺ perovskite is discovered by utilizing the interplay of electron-trapping defect levels and hole-trapping Tb³⁺. It combines an excellent charge carrier storage capacity (≈7 and 12 times higher than state-of-the-art BaFBr(I):Eu²⁺ and Al₂O₃:C), >1200 h storage duration, >40 h afterglow, efficient optically stimulated luminescence, persistent mechanoluminescence, and force-induced charge carrier storage features. Particularly, it well responds to various stimuli channels, i.e., wide-range X-rays to 850 nm infrared photons, thermal activation, mechanical force grinding, or compression. To elucidate this multimode luminescence, charge carrier trapping and release processes in LiTaO₃:0.01Tb³⁺,xGd³⁺ with various physical stimulations will be unraveled by combining the vacuum-referred binding diagram construction, spectroscopy, thermoluminescence, and mechanoluminescence techniques. The versatile and high-performance LiTaO₃:0.01Tb³⁺,xGd³⁺ enables promising proof-of-concept multimode luminescence applications in advanced anti-counterfeiting, flexible X-ray imaging, continuous compression force sensing, and non-real-time recording.

Developing X-ray charged dosimeters with excellent charge carrier storage capacity and stability is challenging. Such energy storage dosimeters have fascinating use in developing novel applications, for instance, in radiation detection, advanced multimode anti-counterfeiting, and flexible X-ray imaging of curved objects. Herein, novel LiTaO₃:Ln³⁺,Eu³⁺ (Ln = Tb or Pr) perovskite dosimeters are reported by combining the vacuum referred binding energy (VRBE) diagram of LiTaO₃ and the optimization of dopant's concentration and compound synthesis condition. Based on the VRBE diagram prediction, charge carrier capturing and de-trapping processes in Eu³⁺ and/or Ln³⁺ (Ln = Tb or Pr) doped LiTaO₃ will be studied to unravel the role of Eu³⁺ as a good electron trapping centre and to discover a record storage phosphor. The ratios of the thermoluminescence intensity of the optimized LiTaO₃:0.005Tb³⁺,0.001Eu³⁺ to that of the state-of-the-art BaFBr(I):Eu²⁺, Al₂O₃:C, or NaLuF₄:Tb³⁺ are 5.2, 8.8, or 2.8, respectively. The charge carriers can be stored more than 1000 h in LiTaO₃:0.005Tb³⁺,0.001Eu³⁺. Proof-of-concept anti-counterfeiting application will be demonstrated by combining the colour-tailorable photoluminescence, afterglow, thermally, or optically stimulated luminescence in LiTaO₃:0.005Tb³⁺,xEu³⁺ and LiTaO₃:0.005Pr³⁺,0.001Eu³⁺. Multimode anti-counterfeiting application will be proposed by combining a high absolute X-ray scintillation light yield of 19000 ± 1800 ph/MeV of LiTaO₃:0.005Tb³⁺,0.001Eu³⁺. Proof-of-concept flexible X-ray imaging application will be demonstrated by using the optimized LiTaO₃:0.005Tb³⁺, 0.001Eu³⁺ dispersed in a silicone gel film.

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.

It is challenging to rational design persistent luminescence and storage phosphors with high storage capacity of electrons and holes after X-ray charging. Such phosphors have potential applications in anti-counterfeiting and X-ray imaging. Here we have combined vacuum referred binding energy diagram (VRBE) construction, photoluminescence spectroscopy, and thermoluminescence to study the trapping processes of charge carriers in NaYGeO₄. In NaYGeO₄:0.004Bi³⁺ and NaYGeO₄:0.004Bi³⁺,0.005Ln³⁺ (Ln = Tb or Pr), Bi³⁺ appears to act as a shallow electron trap, while Bi³⁺ and Ln³⁺ act as deep hole trapping and recombination centres. We will show how to experimentally determine the VRBE in the Bi^{2+ 2}P_1/2 ground state in NaYGeO₄ and NaLuGeO₄ by thermoluminescence study. The electron trap depth produced by Bi³⁺ codopant in NaLu_1-xY_xGeO₄:0.003Bi³⁺,0.008 Tb³⁺ can be adjusted, by increasing x, resulting in conduction band engineering. By combining Bi³⁺ as an electron trap and Bi³⁺ and Tb³⁺ as the hole traps, excellent X-ray charged afterglow phosphors were developed. The integrated TL intensity of the optimized NaYGeO₄:0.004Bi³⁺ and NaYGeO₄:0.003Bi³⁺,0.008Tb³⁺ after exposure to X-rays is about 4.5 and 1.1 times higher than that of the state-of-the-art BaFBr(I):Eu²⁺ storage phosphor. Intense initial Tb³⁺ 4f → 4f afterglow appears in NaYGeO₄:0.003Bi³⁺,0.008Tb³⁺ and more than 40 h afterglow is measurable in NaYGeO₄:0.004Bi³⁺ and NaYGeO₄:0.003Bi³⁺, 0.008 Tb³⁺ after X-ray charging. We will show proof-of-concept anti-counterfeiting and X-ray imaging applications by using the developed afterglow phosphors and CsPbI₃ quantum dots. This work not only provides experimental evidence on the VRBE in the Bi^{2+ 2}P_1/2 ground state in NaYGeO₄, but also shows how to design and develop good afterglow phosphors for anti-counterfeiting and X-ray imaging by deeply studying and controlling the trapping processes of charge carriers in bismuth and/or lanthanides doped inorganic compounds.

Developing X-ray or UV-light charged storage and mechanoluminescence (ML) materials with high charge carrier storage capacity is challenging. Such materials have promising utilization in developing new applications, for example, in flexible X-ray imaging, stress sensing, or non-real-time recording. Herein, the study reports on such materials; Bi³⁺, Tb³⁺, Ga³⁺, or Ge⁴⁺ doped LiTaO₃ perovskite storage and ML phosphors. Their photoluminescence, thermoluminescence (TL), and ML properties are studied. The charge carrier trapping and release processes in the Bi³⁺, Tb³⁺, Ga³⁺, or Ge⁴⁺ doped LiTaO₃ are explained by using the constructed vacuum referred binding energy diagram of LiTaO₃ including the energy level locations of unintended defects, Tb³⁺, Bi³⁺, and Bi²⁺. The ratio of the TL intensity after X-ray charging of the optimized LiTaO₃:0.005Bi³⁺,0.006Tb³⁺,0.05Ga³⁺, or LiTaO₃:0.005Bi³⁺,0.006Tb³⁺,0.05Ge⁴⁺ to that of the state-of-the-art BaFBr(I):Eu²⁺ is ≈1.2 and 2.7, respectively. Force induced charge carrier storage phenomena is studied in the Tb³⁺, Bi³⁺, Ga³⁺, or Ge⁴⁺ doped LiTaO₃. Proof-of-concept compression force distribution sensing and X-ray imaging is demonstrated by using optimized LiTaO₃:0.005Bi³⁺,0.006Tb³⁺,0.05Ga³⁺ dispersed in a hard epoxy resin disc and in a silicone gel film. Proof-of-concept color-tailorable ML for anti-counterfeiting is demonstrated by admixing commercial ZnS:Cu⁺,Mn²⁺ with optimized LiTaO₃:0.005Bi³⁺,0.006Tb³⁺,0.05Ge⁴⁺ in an epoxy resin disc.