Latent Fingerprint Identification Research Articles

Highly crystallization-induced emissive luminophores with mechanoluminescent features for two-photon harvesting fluorescence imaging and latent fingerprint identification

Highly crystallization-induced emissive luminophores with mechanoluminescent features for two-photon harvesting fluorescence imaging and latent fingerprint identification

A ternary dual-emission Eu(III)-functionalized HOF/COF hybrid: Tryptophan, 5-hydroxyindoleacetic acid ratiometric fluorescence detection and latent fingerprint identification

Fluorescent covalent organic framework (COFs) and lanthanide functionalized hydrogen-bonded organic framework have been widely studied in the field of fluorescence sensing due to their excellent properties. To our knowledge, there is no report about HOF/COF composites by combining HOF and COF. In our work, we propose a simple in-situ growth method to synthesize HOF/COF by adding pre-synthesized fluorescent COF into HOF preparation system. Based on the coordination post-synthetic modification, the ternary Eu(III) functional HOF/COF hybrid material (Eu@HOF/COF) is obtained, in which partial organic linkers of HOF are transformed to a new structure induced by Eu(III). At the single excitation wavelength, Eu@HOF/COF has two emission peaks corresponding to COF and Eu(III), respectively, and its luminescence is little affected by water molecules, which is relatively rare in previous work. Eu@HOF/COF, as a ratiometric fluorescence sensor can detect tryptophan and its metabolite 5-hydroxyindoleacetic acid with high selectivity, fast response, good sensitivity and recovery. Eu@HOF/COF has good fluorescence emission of Eu(III) and COF, and a large number of free carboxyl groups of HOF react with residues in latent fingerprint (LFP), which is beneficial in LFP identification. In summary, this study not only provides a useful reference for the construction of hybrid materials with Eu(III) and COF dual-emission centers, but also reveals that the new structure formed after the coordination of Eu(III) and HOF to sensitize Eu(III) luminescence, and also has the potential for the early detection of depression and diagnosis of carcinoid tumors.

Simple synthesis of carbon dots/organosilicon composites with tunable solid-state emission and size for accurate latent fingerprint identification

The CDs–OSi composites with tunable emission and size were prepared by adjusting the volume ratio of H2O and EtOH in solvothermal. The CDs–OSi composites were applied in identification of latent fingerprint with effective definition and contrast.

Solid state reaction preparation of BaMg2Si4O10F2:Eu3+ synthetic-mica phosphor for latent fingerprint identification

Synthetic-mica materials have shown multifunctional performances due to their distinctive adhesion and cation exchange ability. In this work, a novel Eu3+-doped synthetic-mica named as barium tetrasilicate fluorphlogopite (BaMg2Si4O10F2) phosphor was prepared by the high-temperature solid state reaction process for the first time. The as-prepared mica samples possess a distinct lamellar structure, as indexed by X-ray diffraction, scanning and transmission electron microscopy means. The photoluminescence results manifest that the phosphor can generate bright red emission at 614 nm corresponding to the characteristic 5D0→7F2 transition of Eu3+ as excited with UV light, and the luminescence intensity is nearly 9-fold in comparison with that in original fluorphlogopite. The more fantastic result is that the emission intensity at 373 K still retains 95 % in respect to that at ambient temperature, demonstrating the phosphor system with excellent optical thermal stability. The optimal BaMg2Si4O10F2:8%Eu3+ phosphor powder has been used to discern the latent fingerprints on the surface of diverse non-porous and semi-porous substrates, which reveal the superior visibility as irradiated with 254 nm UV light. The Eu3+-doped BaMg2Si4O10F2 synthetic-mica is a promising phosphor material for latent fingerprint identification application.

The inter-molecular hydrogen bonds modulated reversible ACQ-AIE conversion and dual-states sensing applications of shikimic acid derived hydrogen bond dimers

Smart molecules with adjustable and reversible ACQ-AIE transformation which could be used as luminescence sensors both in solvent and solid-state are rarely reported. Planar luminophores with strong inter-molecular hydrogen bonds and a rotor might exhibit reversible ACQ-AIE conversion by modulating the inter-molecular hydrogen bonds. As a proof of concept, herein, two smart hydrogen bond dimers (Qufu-1 and Qufu-2) with reversible ACQ-AIE transformation were derived from the renewable bio-feedstock shikimic acid. Qufu-1 and Qufu-2 possessing a novel 4-oxo-3,4-dihydrobenzofuro[2,3-d]pyrimidine key structure and both exhibit crystallization induced ACQ (CIACQ) and precipitation induced AIE (PIAIE) in solid-state. Single crystal analysis indicates that the large planar configuration formed in the dimers of Qufu-1 and Qufu-2 due to the inter-molecular hydrogen bonds, which would result in the strong π-π stacking and ACQ in crystal. The AIE state could be facile realized by breaking the inter-molecular hydrogen bonds and changing the aggregation state from crystal to precipitation. Moreover, ACQ to AIE transformation could also accomplish for Qufu-1 and Qufu-2 in solution by modulating the inter-molecular hydrogen bonds with acid. In addition, three-level structures latent fingerprint identification in real environment and fluorescent sensing of hazardous biogenic amines in food samples were performed with Qufu-1.

Post-Synthetic Modification of a Fluorescent Covalent Organic Framework as a Multifunctional Sensor for Efficient Detection of 5-Hydroxytryptamine and Its Metabolite and Latent Fingerprint Identification

In this study, a functionalized vinyl-linked 2D fluorescent covalent organic framework (COF) (TMT-TA-COOH) is constructed by post-synthetic modification (PSM) of a TMT-TA COF, which is composed of trimethyltriazine (TMT) and terephthalaldehyde (TA). The fluorescent COF (TMT-TA) has the characteristics of good crystallization and stability, but the dispersibility in water is poor, which requires further PSM. After PSM, the obtained TMT-TA-COOH not only exhibits good dispersibility in water but also displays stronger binding ability to analytes, which presents high sensitivity for quantitative identification of 5-hydroxytryptamine (5-HT) and its metabolite 5-hydroxyindole-3-acetic acid (5-HIAA) in water. Moreover, TMT-TA-COOH can specifically recognize 5-HT in serum and 5-HIAA in urine with a fast response, good anti-interference performance, and real-time visualization, which enables the TMT-TA-COOH to be a tool for early detection of neurological diseases and biomarkers for carcinoid tumors. In addition, TMT-TA-COOH is also a good candidate for latent fingerprint (LFP) identification, which has the characteristics of high contrast and low background interference. This work not only provides a promising platform for the sensing application of fluorescent COFs in aqueous solution but also opens up a new way for the detection of LFP information.

Novel development of zinc oxide-coated carbon nanoparticles from pineapple leaves using sol gel method foroptimal adsorption of Cu2+ and reuse in latent fingerprint application.

This study underlines a latest approach of preparing nitrogen carbon nanoparticles fused on zinc oxide nanoparticle nanocomposite (N-CNPs/ZnONP nanocomposite) for the uptake of copper ions (Cu2+) from wastewater using a sol gel method. The metal loaded adsorbent was then applied in the latent fingerprint application. N-CNPs/ZnONP nanocomposite proved to be a good sorbent for the optimal adsorption of Cu2+ at pH 8 and 1.0g/L dosage. Langmuir isotherm best fitted the process with the maximum adsorption capacity of 285.71mg/g that was superior to most values reported in other studies for the removal of Cu2+. At 25°C, the adsorption was spontaneous and endothermic. Furthermore, Cu2+-N-CNPs/ZnONP nanocomposite revealed to be sensitive and selective for latent fingerprint (LFP) identification on a variety of porous surfaces. As a result, it is an excellent identifying chemical for latent fingerprint recognition in forensic science.

Multifunctional Eu(III)-modified HOFs: roxarsone and aristolochic acid carcinogen monitoring and latent fingerprint identification based on artificial intelligence.

The exploration of multifunctional materials and intelligent technologies used for fluorescence sensing and latent fingerprint (LFP) identification is a research hotspot of material science. In this study, an emerging crystalline luminescent material, Eu3+-functionalized hydrogen-bonded organic framework (Eu@HOF-BTB, Eu@1), is fabricated successfully. Eu@1 can emit purple red fluorescence with a high photoluminescence quantum yield of 36.82%. Combined with artificial intelligence (AI) algorithms including support vector machine, principal component analysis, and hierarchical clustering analysis, Eu@1 as a sensor can concurrently distinguish two carcinogens, roxarsone and aristolochic acid, based on different mechanisms. The sensing process exhibits high selectivity, high efficiency, and excellent anti-interference. Meanwhile, Eu@1 is also an excellent eikonogen for LFP identification with high-resolution and high-contrast. Based on an automatic fingerprint identification system, the simultaneous differentiation of two fingerprint images is achieved. Moreover, a simulation experiment of criminal arrest is conducted. By virtue of the Alexnet-based fingerprint analysis platform of AI, unknown LFPs can be compared with a database to identify the criminal within one second with over 90% recognition accuracy. With AI technology, HOFs are applied for the first time in the LFP identification field, which provides a new material and solution for investigators to track criminal clues and handle cases efficiently.

FingerGAN: A Constrained Fingerprint Generation Scheme for Latent Fingerprint Enhancement.

Latent fingerprint enhancement is an essential preprocessing step for latent fingerprint identification. Most latent fingerprint enhancement methods try to restore corrupted gray ridges/valleys. In this paper, we propose a new method that formulates latent fingerprint enhancement as a constrained fingerprint generation problem within a generative adversarial network (GAN) framework. We name the proposed network FingerGAN. It can enforce its generated fingerprint (i.e, enhanced latent fingerprint) indistinguishable from the corresponding ground truth instance in terms of the fingerprint skeleton map weighted by minutia locations and the orientation field regularized by the FOMFE model. Because minutia is the primary feature for fingerprint recognition and minutia can be retrieved directly from the fingerprint skeleton map, we offer a holistic framework that can perform latent fingerprint enhancement in the context of directly optimizing minutia information. This will help improve latent fingerprint identification performance significantly. Experimental results on two public latent fingerprint databases demonstrate that our method outperforms the state of the arts significantly. The codes will be available for non-commercial purposes from https://github.com/HubYZ/LatentEnhancement.

Zn2SiO4: Mn2+, Yb3+ long afterglow materials prepared employing Zn-based coordination polymer as precursor: Properties, Mechanism and Application

An excellent green persistent luminescence (PersL) phosphor Zn2SiO4: Mn2+, Yb3+ was synthesized through a new method via reacting Zn-based coordination polymer particles with SiO2 submicrospheres. The structure properties including the phase purity, structural parameters and crystal structure were investigated in details. Morphological analysis revealed that Zn2SiO4: Mn2+, Yb3+ retained the morphology of SiO2 submicrospheres with diameter ∼200 nm. The PersL of Zn2SiO4: Mn2+ displayed a remarkably enhanced afterglow duration by codoping with Yb3+, in which the duration time prolonged from 5 min to 114 min (∼23 times) as compared with that of Zn2SiO4 host or singly Mn2+ doped. The depths of the traps responsible for PersL were estimated to be in the range of 0.696–1.112 eV, and an additional trap that are deemed to play a role for the improvement was discussed. The prepared phosphors were successfully used for the latent fingerprint visualization and exhibited high accuracy of fingerprint recognition. These findings not only provids a new synthetic approach for PersL materials with designated morphology and dimensions, but also indicates the product may find applications in advanced latent fingerprint identification, information storage and anticounterfeiting technology.

In-sensor reservoir computing system for latent fingerprint recognition with deep ultraviolet photo-synapses and memristor array

Detection and recognition of latent fingerprints play crucial roles in identification and security. However, the separation of sensor, memory, and processor in conventional ex-situ fingerprint recognition system seriously deteriorates the latency of decision-making and inevitably increases the overall computing power. In this work, a photoelectronic reservoir computing (RC) system, consisting of DUV photo-synapses and nonvolatile memristor array, is developed to detect and recognize the latent fingerprint with in-sensor and parallel in-memory computing. Through the Ga-rich design, we achieve amorphous GaOx (a-GaOx) photo-synapses with an enhanced persistent photoconductivity (PPC) effect. The PPC effect, which induces nonlinearly tunable conductivity, renders the a-GaOx photo-synapses an ideal deep ultraviolet (DUV) photoelectronic reservoir, thus mapping the complex input vector into a dimensionality-reduced output vector. Connecting the reservoirs and a memristor array, we further construct an in-sensor RC system for latent fingerprint identification. The system maintains over 90% recognition accuracy for latent fingerprint within 15% stochastic noise level via the proposed dual-feature strategy. This work provides a subversive prototype system of DUV in-sensor RC for highly efficient recognition of latent fingerprints.

Tuning the morphology of Mg2TiO4: Mn4+ for luminescence performance and latent fingerprint visualization

Mn4+ doped Mg2TiO4 samples were prepared through a solvothermal calcination method. The samples with hollow sphere structure about 400 nm were obtained using a hard template, and the uniform size distribution could be realized by prolonging the aging time. Compared with the solid sphere sample, the Mn4+ doped Mg2TiO4 samples with hollow sphere structure exhibited excellent luminescence performance owing to the boosted radiation light. Simultaneously, the hollow sphere structure with the loose shell could also make the luminescence intensity of Mg2TiO4: Mn4+ improved by reducing the light scattering on the exterior of sphere and enhancing the reflecting in interior of sphere. By the virtues of their strong emission intensities, the samples are applied to visualize the potential fingerprints on the glass surfaces. Under UV light, the pattern and ridge flow of the fingerprint are clearly identified. More importantly, we demonstrated that the Mn4+ doped Mg2TiO4 samples with hollow sphere structure are highly sensitivity in identifying three-level features of fingerprint, such as pores and scars. The advantages for light intensity and resolution of fingerprint images coated with the Mg2TiO4: Mn4+ samples give it potential application in the field of latent fingerprint identification.

Cd2+ ion adsorption and re-use of spent adsorbent with N-doped carbon nanoparticles coated on cerium oxide nanorods nanocomposite for fingerprint detection

This work provides a novel approach to prepare nitrogen-doped carbon nanoparticles (CNPs) coated on a cerium oxide nanorods nanocomposite (N-CNPs/CeO2NRsnC) for the uptake of cadmium (Cd2+) ions and re-using the spent adsorbent, Cd2+-CNPs/CeO2NRsnC for latent fingerprint detection (LFP). N-CNPs were prepared by a thermal method with urea and cabbage powder as precursors. N-CNPs/CeO2NRsnC was developed with N-CNPs and CeO2NRs with a hydrothermal method and characterized by various instrument methods like UV-visible, FT-IR, XRD, BET, XPS, SEM, and TEM. The N-CNPs/CeO2NRsnC had a greater surface area (9.96 m2/g) than N-CNPs (0.64 m2/g). The synthesized N-CNPs/CeO2NRsnC proved to be a good sorbent material to remove Cd2+ from water at a maximum pH 8 and dosage 10 mg/L. The adsorption was spontaneous and endothermic at 25 ºC. In addition, Cd2+-N-CNPs/CeO2NRsnC has been shown to be sensitive and selective for LFP identification on several porous substrates. It is therefore a good labeling agent for latent fingerprint identification in forensic science.

A Study on Automatic Latent Fingerprint Identification System

Latent fingerprints are the unintentional impressions found at the crime scenes and are considered crucial evidence in criminal identification. Law enforcement and forensic agencies have been using latent fingerprints as testimony in courts. However, since the latent fingerprints are accidentally leftover on different surfaces, the lifted prints look inferior. Therefore, a tremendous amount of research is being carried out in automatic latent fingerprint identification to improve the overall fingerprint recognition performance. As a result, there is an ever-growing demand to develop reliable and robust systems. In this regard, we present a comprehensive literature review of the existing methods utilized in latent fingerprint acquisition, segmentation, quality assessment, enhancement, feature extraction, and matching steps. Later, we provide insight into different benchmark latent datasets available to perform research in this area. Our study highlights various research challenges and gaps by performing detailed analysis on the existing state-of-the-art segmentation, enhancement, extraction, and matching approaches to strengthen the research.

Improved stability of all-inorganic perovskite nanocrystals in hierarchical ZSM-5 zeolites for multimodal applications

All-inorganic perovskite quantum dots (PQDs) CsPbX3 (X = Cl and Br) are expected a new generation of promising luminescent materials with narrow-band emissions, color-tunability, and high photoluminescence quantum yields (PLQYs), but the instability towards humid environments and high temperatures restrict their practical applicability. In this work, a hierarchically structured zeolite (HSZ) of ZSM-5 (Si/Al = 50) featured micro-mesoporous cross-linked architecture was applied to encapsulate CsPbX3 PQDs through a simple thermal diffusion strategy. The luminescence performances of CsPbX3 PQDs hybridized ZSM-5 nanocomposites can be optimized in the hierarchical micro-mesoporous structures. Particularly, the CsPbBr3-HSZ ZSM-5 composite calcined at 700 °C exhibited highly water-stable luminescence performance with a full-width at half-maximum (FWHM) of 22 nm and a high photoluminescence quantum yield (PLQY, 62%), maintaining 92% of the initial emission intensity even after 100 days of immersion in water. The highly water-resistant and stable luminescent performance of the composite was attributed to the interconnected micro-mesoporous network of HSZ ZSM-5, in which micropores provide a shielding wall to isolate the CsPbBr3 PQDs from the external environment and mesopores help to promote the diffusivity of precursors towards the successful space-confinement of CsPbX3 (X = Cl and Br) PQDs. The temperature-dependent fluorescence intensity and spectral shift characteristics of CsPbBr3-HSZ ZSM-5 composite afford its capacity acting as dual-mode optical thermometers, and the water-stable latent fingerprint identification has been also demonstrated by applying the CsPbBr3-HSZ ZSM-5 nanocomposite.

A dual-stimuli-responsive intelligent layered lanthanide hydroxide for application in information security and latent fingerprint identification

With the rapid changes in the field of information, the research and development of optical storage materials with high security and large storage capacity are particularly important in the development of contemporary society. However, conventional memory materials with static fluorescent outputs have the disadvantages of easy simulation and forgery, which limits their practical application in the protection of confidential information. In this research, a dual-stimuli-responsive intelligent fluorescent material based on Tb3+ and Eu3+ ions doped layered lanthanide hydroxide (LYH:EuxTb1–xDPA) was fabricated, which can realize reversible multi-color luminescence conversion (from green to red) by varying the pH and temperature. Combined with the Morse code and security pattern, the multiple encryption and decryption of confidential information and anti-counterfeiting can also be realized. Therefore, the obtained intelligent fluorescent material has a great application prospect for information security. In addition, due to the excellent color tunability, the material can provide the possibility to obtain potential fingerprints with high contrast and no background interference on different color substrates. The unique dual-stimuli-responsive behavior of this material provides more ingenious design inspiration for the design of multi-color intelligent fluorescent devices.

Impact of Minutiae Errors in Latent Fingerprint Identification: Assessment and Prediction

We study the impact of minutiae errors in the performance of latent fingerprint identification systems. We perform several experiments in which we remove ground-truth minutiae from latent fingerprints and evaluate the effects on matching score and rank-n identification using two different matchers and the popular NIST SD27 dataset. We observe how missing even one minutia from a fingerprint can have a significant negative impact on the identification performance. Our experimental results show that a fingerprint which has a top rank can be demoted to a bottom rank when two or more minutiae are missed. From our experimental results, we have noticed that some minutiae are more critical than others to correctly identify a latent fingerprint. Based on this finding, we have created a dataset to train several machine learning models trying to predict the impact of each minutia in the matching score of a fingerprint identification system. Finally, our best-trained model can successfully predict if a minutia will increase or decrease the matching score of a latent fingerprint.

Latent Fingerprint Identification System Based on a Local Combination of Minutiae Feature Points

Latent Fingerprint Identification System Based on a Local Combination of Minutiae Feature Points

Construction and Multifunctional Applications of Visible-Light-Excited Multicolor Long Afterglow Carbon Dots/Boron Oxide Composites

Compared to ultraviolet light, visible light as an excitation light source has lower phototoxicity and deeper penetrability. This is of importance to explore the application of long afterglow materials with visible light as the excitation wavelength. In this work, multicolor long afterglow materials excited by visible light were prepared by embedding carbon dots (CDs) in boron oxide (B₂O₃) and the formation of carbon–boron bonds, and the glassy state of B₂O₃ during the heating process protected the triplet excitons from being quenched, thereby promoting the emission of long afterglow. In addition, some CDs/B₂O₃ composites show dual-mode afterglow emission with thermally activated delayed fluorescence (TADF) and room-temperature phosphorescence (RTP) at the same time. These as-designed multicolor CDs/B₂O₃ composites exhibit a long lifetime of 445.9 ms, a high afterglow quantum efficiency of 17.61%, and high stability. Meanwhile, the afterglow can be observed at room temperature by the naked eye and lasts for several seconds when the visible light is just switched off. These as-obtained CDs/B₂O₃ composites with visible-light-excited multicolor long afterglow emission have shown potential in reversible ratiometric temperature sensing, latent fingerprint identification, information anticounterfeiting, and encryption.

Large scale synthesis of red emissive carbon dots powder by solid state reaction for fingerprint identification

Red emissive carbon dots (CDs) powder was synthesized on a large scale from phloroglucinol and boric acid by a novel solid state reaction with yield up to 75%. This method is safe and convenient, for it needs neither high pressure reactors nor complicated post-treatment procedures. The as-prepared carbon dots powder exhibited strong red fluorescence with excitation-independent behavior. XPS measurement and PL spectra suggest that such red fluorescence arise from boron-doped structures in CDs, which increases along with the boron concentration on CDs surface but decreases when the concentration quenching effect takes place. To overcome the aggregation induced fluorescence quenching of the solid CDs powder, the conventional methods are dispersing CDs into a large amount of inert substrates. But our present work provides a new strategy to realize strong red fluorescence of CDs in solid state. As a result, such carbon dots powder works well for latent fingerprint identification on various material surfaces.