Development of red-emitting Ba2LaSbO6:Mn4+ phosphors for latent fingerprint detection

Latent fingerprints provide crucial affirmations of identity in forensic science. However, they are microscopic. In this study, novel fluorescence materials, Ba₂LaSbO₆:Mn⁴⁺ (BLSO:Mn⁴⁺) phosphors, were developed by a sol–gel method for the fluorescence imaging of latent fingerprints. The structural properties of the phosphors were investigated by powder X-ray diffraction (XRD) and its Rietveld refinement analyses, and transmission electron microscopy and scanning electron microscopy techniques. The photoluminescence properties of the BLSO:Mn⁴⁺ phosphors were evaluated comprehensively by recording the emission, excitation, and decay curves. The BLSO:Mn⁴⁺ phosphors provide a high-intensity red emission at 677 nm under 350 nm excitation caused by the ²E_g→⁴A_2g transition of Mn⁴⁺. The optimum concentration of Mn⁴⁺ in the BLSO host was determined to be ~0.2 mol%. The calculated Commission International de L'Eclairage (CIE) chromaticity coordinates (0.716, 0.283) of the emission from the BLSO:Mn⁴⁺ phosphor are located in the pure red region of the CIE 1931 diagram. The red-emitting BLSO:0.2Mn⁴⁺ phosphor was used as a fluorescence imaging powder for visualizing latent fingerprints on various substrates with high resolution, high contrast, and high efficiency, as well as good selectivity.     

A highly intense double perovskite BaSrYZrO5.5: Eu3+ phosphor for latent fingerprint and security ink applications

A novel double perovskite BaSrYZrO_5.5:Eu³⁺ red-emitting phosphor was synthesized and characterized by XRD, SEM and PL analyses. The structure of the prepared phosphor was confirmed through JCPDS as well as Rietveld refinement analysis. The present phosphor shows an intense red emission at 613 nm when excited by 394 nm. The CIE colour coordinates value of BaSrYZrO_5.5:Eu³⁺ (9 mol%) phosphor is found to be (0.6181, 0.3783) and it has high colour purity of 99.1%. The 613 nm transition integrated intensity of the present phosphor is 4.44 times higher compared to the commercial red phosphor. The thermal stability and Quantum yield of optimized BSYZ:Eu³⁺ (9 mol%) phosphor were also calculated. The BSYZ:Eu³⁺ phosphor results can be employed as an efficient red component in latent fingerprint detection and anti-counterfeiting applications.     

A turn-on fluorescent solid-sensor for Hg(II) detection

A rhodamine organosilane derivative (Rh-UTES) has been obtained by one-pot synthesis. The chemical structure of Rh-UTES was confirmed by nuclear magnetic resonance (NMR) and infrared (FTIR) techniques. To obtain an inorganic-organic hybrid sensor, Rh-UTES was covalently immobilized on a porous silicon microcavity (PSiMc) via triethoxysilane groups. The attachment of the organic derivative into PSiMc was confirmed by FTIR, specular reflectance, and scanning electron microscopy (SEM). The optical performance of Rh-UTES receptor for Hg²⁺ detection was investigated by fluorescent spectroscopy and microscopy. Upon the addition of increasing amounts of Hg²⁺ ions, a remarkable enhancement in emission intensity was produced in both systems. In the solid phase, an increase of integrated fluorescent emission of 0.12- and 0.15-fold after Hg²⁺ receptor coordination was observed. The light harvesting capability of PSiMc devices allowed obtaining an enhanced fluorescent emission after Rh-UTES immobilization (277-fold). The fluorescence microscopy of hybrid PSiMc sensor provided an optical qualitative test for Hg²⁺ detection.     

海洋溢油化学指纹分析鉴定方法探讨

石油资源分布不均推动石油勘探和运输规模不断扩大,溢油事故日益增多,包括井喷,船舶漏油等,带来环境损害评估等问题。油指纹分析鉴定通过研究油品风化周期,推断溢油对环境的影响时间,通过生物毒性实验判断对环境影响程度。为事故调查处理提供科学依据,包括缩小调查对象范围,确定溢油来源种类。针对当前溢油鉴定中的问题进行研究,表明油品混合可能存在化学变化,扩大混合前油品特征比值差异,正构烷烃特征比值与萜烷类特征比值相同,可能为不同油品,说明多采集油品特征信息是溢油鉴定的重要基础。     

The use of fluorescent probes for the detection of under-film corrosion

An inexpensive and practical method for detecting under-film aluminium corrosion using a hand-held UV inspection lamp is described. A novel fluorescent probe for under-film iron corrosion is demonstrated. Studies of light transmission and ion transport through three types of paint film show polyester to be the best barrier to ions and epoxy to be the most transparent in the near UV.     

Synthesis of Li+-ion activated NaYF4: Er3+/Yb3+ phosphors via a modified solid-state process for latent fingerprint detection

Li⁺-ion codoped NaYF₄: Er³⁺/Yb³⁺ phosphors (β-NaYF₄) with a hexagonal structure were synthesized via a modified solid-state route. High-speed planetary ball milling and solid-liquid mixing were simultaneously used to overcome the drawbacks of high synthesis temperatures in conventional routes. A pure β-NaYF₄ phase was obtained through calcination at 600?°C for 3?h. Increases in the codoping content of Li⁺ ion caused a slight shift in X-ray diffraction peak positions toward high angles owing to the distortion of the local crystal field. Field emission scanning electron microscope images showed agglomerated spherical particles of approximately 0.7?µm with narrow size distribution. The upconversion properties of β-NaYF₄ codoped with Li⁺-ion were explored. Two emission bands in the green regions (520?nm and 545?nm) and one emission band in the red region (615?nm) were observed owing to the ²H_11/2→⁴I_15/2, ⁴S_3/2→⁴I_15/2, and ⁴F_9/2→⁴I_15/2 transitions of Er³⁺, respectively. Codoping with 6?mol% Li⁺ increased the upconversion intensity by three times, which was explained using the energy level diagram. The present phosphors with improved upconversion properties were utilized for latent fingerprint detection on smooth surfaces of regularly used polymer sheets, glass substrates, and compact discs. Using the present phosphors, the base elements with three-level features, such as sharp ridges, valleys, ridge flow, bifurcation, ridge shapes, and dots, were observed on all hydrophilic and hydrophobic surfaces. The prepared phosphors exhibited promising characteristics to detect the features of fingerprint impression for individual identification in forensic applications.     

A polymer based fluorescent sensor for Zn detection and its application for constructing logic gates

A polymer-based fluorescent sensor was synthesized by polymerization of (S)-6,6′-dibutyl-3,3′-(di-5-salicylde-ethynyl)-2,2′-binaphthol (M-1) with (R,R)-1,2-diaminocyclohexane (M-2) via nucleophilic addition-elimination reaction. The responsive optical properties of the polymer on transition metal ions were investigated by fluorescence and UV-vis spectra. The polymer (1.0 × 10⁻⁵ mol/L in THF) could emit fluorescence at 550 nm and exhibit high selectivity for sensing Zn²⁺ with 36.1-fold fluorescence enhancement. Three logic gates were designed according to the different fluorescence responses of this polymer sensor to Zn²⁺ and Cu²⁺.     

适用于催化剂和发光材料研究的并行合成和高通量表征技术

介绍了作者课题组近年来所发展的适用于催化材料和发光材料研究的并行合成和高通量表征技术,以及在新材料筛选方面开展的工作。在并行合成方面包括组合喷射合成仪、微型阵列式溶液燃烧技术以及结合四元掩模和连续掩模的磁控溅射和脉冲激光沉积系统;高通量表征部分包括真空紫外荧光照相系统和组合光谱扫描仪、红外热成像筛选装置和同步辐射红外光谱成像系统。最后,简要介绍了利用所发展的组合技术在稀土聚合物敏化发光材料、真空紫外荧光材料以及可见光响应光催化材料方面开展的工作。     

A novel far-red phosphors Li2ZnTi3O8:Cr3+ for indoor plant cultivation:Synthesis and luminescence properties

A novel far-red phosphors Li₂ZnTi₃O₈:Cr³⁺ were successfully synthesized via the conventional solid-state method. The structural characteristics, luminescence properties and concentration quenching of the Li₂ZnTi₃O₈:Cr³⁺ phosphors were investigated systematically. Under the excitation at 360 nm and 468 nm, the Li₂ZnTi₃O₈:Cr³⁺ phosphors displays the emission spectra in the range from 600 nm to 850 nm. The far-red emission centered at 735 nm was attributed to the spin-forbidden ²E→⁴A₂ transition of Cr³⁺ ions. The research results of this paper indicate that the phosphors Li₂ZnTi₃O₈:Cr³⁺ has prospective applications in indoor plant cultivation.     

CdTe/CdS核壳量子点的合成和指纹检测研究

本文用水相合成法分别合成了巯基乙酸和谷胱甘肽修饰的CdTe/CdS量子点,讨论了不同反应时间对量子点大小的影响。发现随着回流时间延长量子点的粒径逐渐变大,其荧光发射及吸收峰位置也发生相应的红移,从而量子点发光颜色呈现递变。鉴于量子点这一优良的发光特性,将其应用于光滑客体表面潜在指纹的显现,结果表明此方法灵敏度高,简便,快速。     

Glass-ceramic phosphors for solid state lighting: A review

Solid state lighting, including phosphor converted light-emitting diodes (LEDs) and laser diodes (LDs), have released high demand to develop thermally stable phosphors. For this purpose, inorganic glass-ceramics (GCs) embedded with phosphor particles can act as competitive candidates. They are superior to traditional phosphors or resin/silica composites through successfully overcoming thermal aging and color temperature drifting problems and simultaneously maintaining high luminescent efficiencies. Inorganic GC phosphors can be classified into devitrified glass-ceramics, PiG (Phosphor-in-Glass) and sintered glass-ceramics. This review summarized the recent progress on LED/LD GC phosphors from the aspects of design principles, synthesis methods, microstructure-property relationships and their application studies. In addition, some challenging issues (e.g., crystallization behavior of luminous phase in glass, corrosion behavior of phosphor by glass matrix) are also discussed in detail. Significant issues of glass-ceramics packed LED/LD, such as luminescence efficiency, chromaticity, correlated color temperature and color gamut, are sorted out as well. Potential research directions are further suggested for not only developing new glass-ceramic phosphors but feeding upon various practical application.     

指纹特征-毛细管气相色谱法定性检测大米中矿物油

针对皂化法鉴定矿物油的不足,利用毛细管气相色谱仪,结合矿物油组成特点建立了大米中矿物油气相色谱指纹定性检测方法,通过比较大米提取物的色谱峰组成来对大米是否掺加矿物油进行定性,方法定性可靠直观,应用到大米的检测中效果良好。     

Mechanism-based fluorescent reporter for protein kinase A detection

A novel mechanism-based fluorescent reporter was designed for the detection of protein kinase A (PKA), which is known to mediate a variety of cellular responses in most eukaryotic cells. The probe consists of a specific binding peptide sequence, LRRRRFAFC, conjugated with 2'-thioethyl-5-(or -6)-carboxyfluoresceinamide (FAMS; 2) and 5-(or 6-)carboxytetramethylrhodamine (TAMRA) at the cysteine and leucine residues, respectively. In the absence of PKA, the two fluorophores associate by hydrophobic interactions, forming an intramolecular ground-state dimer; this results in fluorescein quenching (>93 %). Upon PKA addition, the reporter reacts with the sulfhydryl functionality at Cys199 through a disulfide-exchange mechanism. FAMS is subsequently released, resulting in significant fluorescence amplification. The remaining peptide sequence, which acts as an inhibitor, is attached covalently to the enzyme. Our results suggest that this type of sensors could have far-reaching applications in the molecular sensing of enzymes.     

Design and development of fluorescent nanostructures for bioimaging

Because fluorescence-based techniques are inherently sensitive, selective, convenient, diverse, non-destructive, potentially real time and in situ, they have been widely used in biological imaging. Especially those, with specific fluorescent nanostructures (FNSs) as detecting media in bioimaging, have already been intensively studied for more than a decade because of the convenient transduction of optical signal, high sensitivity and rapid response of FNSs. In this review, we summarize the major strategies to design FNSs with specific structures for biological imaging. First, recent advances are briefly introduced. Then, the specific design of FNSs and their applications are reviewed, in which their fluorescence mechanism, strategies in designing and development, preparation methods, and some representative applications in bioimaging are described. Finally, future perspectives and ongoing issues of FNSs and their applications in bioimaging are discussed. Although many FNSs have been synthesized and applied biologically, many studies still should be done before they can be widely employed as fluorescent probes in clinical tests. With further advances in design and synthesis of high quality multifunctional FNSs, the widespread application of FNSs may be expected not only in advanced bioimaging, but also in ultra-sensitive molecular diagnosis, novel light-emitting nanodevices and intracellular drug delivery.     

Preparation and photoluminescence properties with the site‐selected excitations of Bi3+‐activated Ba3Sc4O9 phosphors

A series of novel Bi³⁺‐doped Ba₃Sc₄O₉ phosphors were synthesized through the solid‐state reaction. Their photoluminescence, decay curves, and thermal quenching properties were investigated in detail. The Ba₃Sc₄O₉:Bi³⁺ phosphors could be efficiently excited in the ultraviolet and near‐ultraviolet region (300‐400 nm), and the photoluminescence properties possess an obvious site‐selected excitations phenomenon. When excited at the ultraviolet light (320‐360 nm), the phosphors present a green or a bluish green emission, and when excited at the near‐ultraviolet light (370‐390 nm), the phosphors always show a yellow emission. The emission spectra excited at the different wavelength can be decomposed into four components, which accord with the four cationic sites in the structure of Ba₃Sc₄O₉. The influence of the Bi³⁺ concentration on the photoluminescence properties is also investigated. Upon excitation at 330 and 377 nm, the Ba₃Sc₄O₉:Bi³⁺ both have good thermal quenching properties; their emission intensity of the peak at 150°C both exceed 60% of the initial value. The above results indicate that the Ba₃Sc₄O₉:Bi³⁺ phosphor is a promising candidate to provide green or yellow components for UV or near‐UV LEDs.     

Combustion synthesis of borate phosphors for use in plasma display panels and mercury-free fluorescent lamps

Discussed are the photoluminescence properties of combustion synthesized red and green emitting borate phosphors—YBO₃ : Eu³⁺, BaZr(BO₃)₂ : Eu³⁺, YCaBO₄ : Eu³⁺, YAl₃(BO₃)₄ : Eu³⁺, YAl₃(BO₃)₄ : Tb³⁺, LaBaB₉O₁₆ : Tb³⁺, LaBaB₉O₁₆ : (Ce³⁺,Tb³⁺), and Na₃La₂(BO₃)₃ : Tb³⁺-promising for use in plasma display panels and mercury-free fluorescent lamps.     

A highly selective fluorescent sensor for Hg based on the water-soluble poly(p-phenyleneethynylene)

The conjugated polymer P-1 could be synthesized by the polymerization of 4,7-diethynyl-benzo[2,1,3]thiadiazole (M-1) and 1,4-bis[3′-(N,N-diethylamino)-1′-oxapropyl]-2,5-diiodobenzene (M-2) via Pd-catalyzed Sonogashira reaction. The water-soluble conjugated polyelectrolyte P-2 could be obtained by the reaction of P-1 with ethyl bromide. Both P-1 and P-2 can emit orange fluorescence. The responsive optical properties of P-1 and P-2 on Hg²⁺ were investigated by fluorescence spectra. Hg²⁺ can lead to nearly complete fluorescence quenching of P-1. On the contrary, Hg²⁺ can show the most pronounced fluorescence enhancement response of P-2 in aqueous solution without interference from those coexistent ions, such as K⁺, Mg²⁺, Pb²⁺, Co²⁺, Ni²⁺, Ag⁺, Cd²⁺, Cu²⁺, Fe³⁺ and Zn²⁺. The results also exhibit that this kind of water-soluble conjugated polyelectrolyte can be used as a highly sensitive and selective fluorescence sensor for Hg²⁺ detection in water.     

Phase formation and spectral evolution of (Sr,Ba)2Si(O,N)4:Eu2+ phosphors

Sr_2‐xBa_xSi(O,N)₄:Eu²⁺ (SB_xSON:Eu²⁺) oxynitridosilicate phosphors were prepared via incorporation of N^3?, Eu²⁺, and Ba²⁺ ions into Sr₂SiO₄ (SSO) lattices. X‐ray diffraction patterns of the prepared powders revealed that SB_xSON:Eu²⁺ was a solid‐solution form of SSO. An increase in x values caused a phase transition and an expansion of the unit cell. The photoluminescence excitation (PLE) spectra of SB_xSON:Eu²⁺ were broad, covering the ultraviolet range to the visible range. Corresponding PL emission spectra strongly depended on the excitation wavelengths and consisted of two emission bands, one in the green‐blue region (A‐band) and the other in the red region (B‐band), which were assigned to Eu(I) and Eu(II), respectively. The B‐band resulted from a dramatic red‐shift of the green emission band assigned to Eu(II) of SSO:Eu²⁺, revealing that the nitridation process preferentially affected the Eu(II) sites. This behavior was explained by crystal field splitting, the fluorescence decay time, and thermal quenching. The Ba²⁺ substitution caused evolution of the PL spectra, and its effects on the spectra were discussed under consideration of ionic size and covalence.     

A ratiometric fluorescent sensor for zinc(II) with high selectivity

Spectroscopic studies revealed that the compound [N,N′-di(quinoline-2-methylene) -1,2-phenylenediimine] (1) exhibited a rather high selectivity toward Zn²⁺ over other metal ions, even Cd²⁺. In acetonitrile, the red shift of fluorescent emission from 396 nm to 426 nm upon zinc binding is due to the formation of a 1:1 metal/ligand complex.