Multimodal Luminescent Yb³⁺/Er³⁺/Bi³⁺‐Doped Perovskite Single Crystals for X‐ray Detection and Anti‐Counterfeiting

Abstract

luminescence, and also the recent hologram technique. [1-3] Compared to other conventional techniques, the fluorescence printing patterns supply promising high security to the key information valuable documents due to the tunable emission properties. [4,5] As counterfeiting technology has also been quickly developed, the traditional mono-mode anti-counterfeiting is far from the requirement of practical applications to guarantee a high level of data and information safety. The traditional anti-counterfeiting luminescence is achieved by the mono-mode downshifting (DS) luminescence, which converts the high energy photon into lower energy luminescence. To address such concern, developing more complicated anti-counterfeiting techniques by increasing the luminescent modes becomes the most challenging topic. Presently, the realization of concurrent upconversion (UC) and DS have been successfully utilized in anti-counterfeiting based on the lanthanide-based dopants. [6-9] The Eu-doped down-shift luminescent materials have been applied in the Euro banknotes, which enables the visible photoluminescence (PL) based on UV lamp excitation. Meanwhile, the Bank of China also introduced the Yb/Er-doped UC phosphors in the banknotes as the counterfeiting technique, which emits the Anti-counterfeiting techniques have become a global topic since they is correlated to the information and data safety, in which multimodal luminescence is one of the most desirable candidates for practical applications. However, it is a long-standing challenge to actualize robust multimodal luminescence with high thermal stability and humid resistance. Conventionally, the multimodal luminescence is usually achieved by the combination of upconversion and downshifting luminescence, which only responds to the electromagnetic waves in a limited range. Herein, the Yb 3+ /Er 3+ /Bi 3+ co-doped Cs 2 Ag 0.6 Na 0.4 InCl 6 perovskite material is reported as an efficient multimodal luminescence material. Beyond the excitation of ultraviolet light and nearinfrared laser (980 nm), this work extends multimodal luminescence to the excitation of X-ray. Besides the flexible excitation sources, this material also shows the exceptional luminescence performance, in which the X-ray detection limit reaches the level of nGy s −1 , indicating a great potential for further application as a colorless pigment in the anti-counterfeiting field. More importantly, the obtained double perovskite features high stability against both humidity and temperature up to 400 °C. This integrated multifunctional luminescent material provides a new directional solution for the development of multifunctional optical materials and devices.

Broadband Detection of X‐ray, Ultraviolet, and Near‐Infrared Photons using Solution‐Processed Perovskite–Lanthanide Nanotransducers

“…In addition, the experimental results demonstrate that the use of mSiO 2 ‐shell coating leads to high material stability under continuous X‐ray, UV, and NIR excitations (Figure S12, Supporting Information). Based on the multicolor properties of UCNPs@mSiO 2 @MAPbX 3 composites, multi‐mode luminescence anti‐counterfeiting can be realized [ 8 ] (Figures S13 and S14, Supporting Information).…”

“…Recently, low‑temperature solution‑processed metal‐halide perovskite materials have emerged as a class of photoactive semiconductors that are technologically attractive for development of the next‐generation optoelectronic devices. [ 6–12 ] Highly sensitive photodetectors using perovskite materials as an active layer have been extensively studied to realize the performance in photodetection of UV–vis light, [ 13–15 ] and X‐rays, [ 16–20 ] respectively. This is mainly benefitted from their low‐cost fabrication and excellent optoelectronic properties such as long carrier diffusion length, high carrier mobility, and large UV–vis and X‐ray absorption coefficient.…”

Halide perovskites scintillators: unique promise and current limitations

“… 88 Higher doses have also been tolerated by PVK scintillators, with Cs 2 Ag 0.6 Na 0.4 In 0.85 Bi 0.15 Cl 6 showing negligible losses after 50 hours and a 34 Gy cumulative dose, 78 whereas 800 Gy reduced the RL intensity of CsPbBr 3 NCs with an organic dye to just 85% of its initial value. 75 Although reductions in light output begin to show at these doses 74 – tridoped Cs 2 Ag 0.6 Na 0.4 InCl 6 :Yb 3+ /Er 3+ /Bi 3+ reduced its RL to 49% after 53 Gy 89 – they still outperform traditional materials, as CsI:Tl emission dropped to 28% after the same dose. An improved understanding of the degradation mechanisms from more focussed studies correlating the effect of the high-energy radiation on both the PVK material and the scintillation performance would benefit the field enormously.…”

Lattice Doping of Lanthanide Ions in Cs 2 AgInCl 6 Nanocrystals Enabling Tunable Photoluminescence

“…Generally, lanthanide (Ln 3+ ) ions would be the most suitable dopants for their rich and unique PL emissions in the visible to near-infrared range [28,29], which could be utilized to achieve tunable luminescence and increased PLQY [30]. Moreover, the successful incorporation of rare earth ions for the lead-based halide perovskites [31,32] and the structural similarity between lead-based and lead-free perovskites (both with the six octahedral coordination number) have provided the reference and opportunities to conduct the further lanthanide doping study on Cs 2 AgInCl 6 NCs [33][34][35].…”