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To better understand the relationship between molecular structure of the mono-/bis-BF 2 -core compounds and mechanofluoroboron behaviors, two pyridine-based difluoroboron compounds with triphenylamine group (TPA-ts-BF 2 and TPA-ts-2BF 2 ) were designed and successfully synthesized, which TPA-ts-BF 2 including a BF 2 fluorophore and TPA-ts-2BF 2 containing the bisBF 2 fluorophores. Based on the photophysical properties measurements results, it was found that TPA-ts-2BF 2 had more excellent intramolecular charge transfer characteristics than that of TPA-ts-BF 2 , and exhibited significant aggregation-induced emission activity, however, TPA-ts-BF 2 displayed typical aggregation-caused quenching phenomenon. Meanwhile, the emission spectrum of the solid powders of TPA-ts-2BF 2 was red-shifted 52 nm after grinding, that of TPA-ts-BF 2 was red-shifted 46 nm, which was resulted from crystalline state switching to amorphous state. According to the theoretical calculations, we conjectured that TPA-ts-BF 2 with uncoordinated amide linkage moiety had a tendency to forming a more twisted conformance and higher molecular polarity, which made that mechanofluorochromic behavior was worse than that of TPA-ts-2BF 2 . Additionally, TPA-ts-2BF 2 was applied to latent fingerprint detection due to its prime aggregation-induced emission property., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Diverse strategies have been developed to visualize latent fingerprints (LFPs) that are undetectable by the naked eye. Among them, fluorescence-based approaches have emerged as an attractive method for enabling high-resolution LFP imaging. However, the use of fluorescent probes for LFP detection remains challenging due to cumbersome processing, low selectivity, and high background interference. Here, we demonstrate highly efficient, sensitive, and background-free LFP detection with dual-color emission arising from manganese (Mn)-doped lead halide perovskite (CsPb(Cl 1-y Br y ) 3 ) nanocrystals (NCs). The resulting bright, fluorescent, solid-state nanopowder (NP) permits the visualization of LFP ridge structures and the resolution of level 1-3 LFP features. The dual-color emission of the Mn-doped perovskite NP provides a simple, robust, and effective route to overcome background interference, thereby increasing the resolution and sensitivity of the LFP detection. The combination of the high quantum efficiency and dual emission of Mn-doped perovskite NP offers great potential for forensic science.

The present work elucidates the fabrication of Barium Lanthanum Oxide nanosheets (BaLa 2 O 4 NSs) via a simple one-pot precipitation method. The acquired results show an orthorhombic crystal system with an average crystallite size of 27 nm. The morphological studies revealed irregular-shaped sheets stacked together in a layered structure, with the confirmation of the precursor elements. The diffused reflectance studies revealed a strong absorption between 200 nm and 350 nm, from which the band-gap energy was evaluated to be 4.03 eV. Furthermore, the fluorescence spectrum was recorded for the prepared samples; the excitation spectrum shows a strong peak at 397 nm, attributed to the 4 F 7/2 → 4 G 11/2 transition, while the emission shows two prominent peaks at 420 nm ( 4 G 7/2 → 4 F 7/2 ) and 440 nm ( 4 G 5/2 → 4 F 7/2 ). The acquired emission results were utilized to confirm the color emission using a chromaticity plot, which found the coordinates to be at (0.1529 0.1040), and the calculated temperature was 3171 K. The as-prepared nanosheets were utilized in detecting latent fingerprints (LFPs) on various non-porous surfaces. The powder-dusting method was used to develop latent fingerprints on various non-porous surfaces, which resulted in detecting all the three ridge patterns. Furthermore, the as-synthesized nanosheets were used to degrade methyl red (MR) dye, the results of which show more than 60% degradation at the 70th minute. It was also found that there was no further degradation after 70 min. All the acquired results suggest the clear potential of the prepared BaLa 2 O 4 NSs for use in advanced forensic and photocatalytic applications.

Multifunctional solid-state luminescent materials are strongly desired in a wide variety of applications. In this work, green emissive carbon dots@montmorillonite (g-CDs@MMT) composites were synthesized based on green emissive carbon dots and MMT clays in a convenient method by embedding g-CDs into the MMT clays. Due to the confinement of g-CDs in the layered structure of the MMT clay matrix, g-CDs are uniformly dispersed in the resulting g-CDs@MMT solid-state composites. This efficiently prevents the aggregation-induced solid-state luminescence quenching of g-CDs, and a photoluminescence quantum yield of 11% could be achieved by the g-CDs@MMT composites under a 405 nm light. Additionally, the g-CDs@MMT composites exhibit low-toxicity, excellent thermal stability, photostability, resistance to organic solvents, and a small particle size. All of these advantages enable applications in fabricating white light-emitting diodes with different color temperatures, where the g-CDs@MMT composites are applied as the color conversion layer. Furthermore, by using the g-CDs@MMT composites as a fluorescence labeling marker, the latent fingerprint detection on a variety of object surfaces could be realized., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Nile red has been an alternative reagent for detecting latent fingerprints on wetted substrates. However, the presence of methanol in nile red solution could make injury to handlers and destroy the traces on surfaces, such as texts on thermal papers. A novel small particle reagent formulation constituting of mesoporous silica nanoparticles (MSNs) based on nile red was prepared to overcome the problem. Compared with the conventional reagents Oil Red O or nile red solution, the nile red-loaded MSNs are highly selective to lipid residues of fingerprints and showed a greater ability to develop clear, sharp, and detailed fingerprints on thermal papers after these were immersed in water. In addition, it can retain texts on the thermal papers well and use only water as a solvent. These suggested that nile red-loaded MSNs are a safe, efficient, and convenient method to develop latent fingerprints on wide range of substrates of forensic importance., (© 2018 American Academy of Forensic Sciences.)

Fingerprint fluorescence imaging has become one of the most prominent technologies in the field of forensic medicine, but it seldom considers the security protection of detection information, which is of great importance in modern society. Herein we demonstrate that luminescent Tb III -carboxymethyl cellulose (CMC) complex binding aptamer hydrogels that are reversibly responsive to ClO - /SCN - can be used for the selective detection, protection, and storage of fingerprint information. The imaging information of the fingerprint can be quenched and recovered by ClO - /SCN - regulation, respectively, resulting in reversible on/off conversion of the luminescence signals for the encryption and decryption of multiple levels of information. The present study opens new avenues for multilevel imaging, data recording, and security protection of fingerprint information with tunable fluorescent hydrogels., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)