Thermally Induced Reversible Fluorescence Switching of Lead Chloride Hybrids for Anticounterfeiting and Encryption

Abstract

Metal halide hybrids with thermally induced fluorescence transition have the potential to be utilized as the next generation of smart materials in optoelectronic devices. However, the fabrication of thermochromic materials with simultaneously reversible and lower transition temperatures is still a challenge. Herein, we present a novel one-dimensional (1D) organic–inorganic lead chloride hybrid (TPA)PbCl3-Green (TPA = tetrapropylammonium) single crystal that exhibits green emission and up to 30% photoluminescence quantum yield (PLQY). It is worth noting that the (TPA)PbCl3-Green crystal changes emission from green to blue light when heated at 323 K. The emission spectra indicate that the blue light is attributed to the combination of two emission peaks located at 438 and 520 nm, respectively. Furthermore, the green luminescence is restored after natural cooling to room temperature. The dynamic transition process is demonstrated via steady-state photoluminescence, single-crystal X-ray diffraction (SCXRD), and powder X-ray diffraction (XRD). (TPA)PbCl3-Green crystals and (TPA)PbCl3-Green@PVP complexes have also been explored as fluorescent security inks for dynamic anticounterfeiting and message encryption as well as optical logic gate applications due to the excellent cycling stability and low transition temperature. This material offers a completely new option for thermochromic materials used for security information.

High‐Temperature, Reversible, and Robust Thermochromic Fluorescence Based on Rb2MnBr4(H2O)2 for Anti‐Counterfeiting

“…The latter ones usually can only survive several cycles and even reported inorganic materials can survive less than 40 cycles. [3,8,30] Compared with other TFMs based on the metal halide perovskites, Rb 2 MnBr 4 (H 2 O) 2 possesses the highest thermochromic fluorescence temperature among reported results with higher stability (Table S3, Supporting Information). The outstanding reversibility for Rb 2 MnBr 4 (H 2 O) 2 crystals holds promising stimuliresponsive applications.…”

“…Therefore, developing thermochromic fluorescence materials (TFMs), especially those responding under extreme temperature conditions, for advanced photonics application is significant and has recently attracted much attention. Xie et al reported that (TPA)PbCl 3 -green possessed sensitive reversible thermochromic fluorescence, which exhibited green emission at room temperature and transformed to (TPA)PbCl 3blue with blue emission at 323 K. [8] Besides, other hybrid metal halides, such as Sb 3+ , Cu + , and Mn 2+ related halides, with fascinating temperature-responsive PL switching behavior have also been reported. Huang et al observed reversible structural and PL transformation triggered by moisture or heat in hybrid chloroantimonates (III).…”

“…Xie et al. reported that (TPA)PbCl 3 ‐green possessed sensitive reversible thermochromic fluorescence, which exhibited green emission at room temperature and transformed to (TPA)PbCl 3 ‐blue with blue emission at 323 K. [ 8 ] Besides, other hybrid metal halides, such as Sb 3+ , Cu + , and Mn 2+ related halides, with fascinating temperature‐responsive PL switching behavior have also been reported. Huang et al.…”

“…The durability and operation reversibility of the hybrid halides and organic materials against temperature are unsatisfactory due to the organic component, which cannot endure high temperature and can only work under mild temperature conditions. [ 8,12 ] Then, they can easily be replicated or imitated and in particular, the organic materials are usually in the face of synthetic and purification challenges. [ 13 ] Theoretically, inorganic metal halides are relatively more suitable for practical application in light of their higher stability.…”

Temperature-Induced Reversible Fluorescence Discoloration of Cs3Cu2Br5 and Its Application in X-ray Imaging

“…All-inorganic metal halide materials also have ultralow X-ray detection limits. , These excellent properties make them a strong competitor to conventional scintillators . Additionally, research has shown that certain materials exhibit significant changes in their photoluminescence (PL) colors with temperature, – which are commonly referred to as thermochromic fluorescent materials. Owing to their high responsiveness under special temperature conditions, their use in advanced photonics applications is significant and has recently attracted considerable attention.…”