Emission Centers Research Articles

Glutathione-capped gold nanoclusters as near-infrared-emitting efficient contrast agents for confocal fluorescence imaging of tissue-mimicking phantoms.

An innovative research has been conducted focused on demonstrating the ability of novel dual-emissive glutathione-stabilized gold nanoclusters (GSH-AuNCs) to perform bright near-infrared (NIR)-emitting contrast agents inside tissue-mimicking agarose-phantoms via two complementary confocal fluorescence imaging techniques. First, using a new and fast microwave-assisted approach, we synthesized photostable dual-emitting GSH-AuNCs with an average size of 3.2 ± 0.4 nm and NIR emission quantum yield of 9.9%. Steady-state fluorescence measurements coupled with fluorescence lifetime imaging microscopy (FLIM) assays performed on lyophilized GSH-AuNCs revealed that the obtained GSH-AuNCs exhibit PL emissions at 610nm (red PL) and, respectively, 800nm (NIR PL) in both solution and powder solid-state. Time-resolved fluorescence measurements showed that the two PL components are characterized by average lifetimes of 407ns (red PL) and 1821ns (NIR PL), respectively. Additionally, due to a partial overlap between the red PL and the absorption of the NIR PL, an energy transfer between the two coexisting emissive centers was discovered and confirmed via steady-state and time-resolved fluorescence measurements. Furthermore, the FLIM analysis performed on powder GSH-AuNCs under 640nm, an excitation more suitable for bioimaging applications, revealed a homogeneous and photostable NIR PL signal from GSH-AuNCs. Finally, the ability of GSH-AuNCs to operate as reliable NIR-emitting contrast agents inside tissue-mimicking agarose-phantoms was demonstrated here for the first time via complementary FLIM and re-scan confocal fluorescence imaging techniques. In consequence, GSH-AuNCs show great promise for future in vivo imaging applications via confocal fluorescence microscopy.

Hybrid Carbon Nanotubes-Graphene Nanostructures: Modeling, Formation, Characterization.

A technology for the formation and bonding with a substrate of hybrid carbon nanostructures from single-walled carbon nanotubes (SWCNT) and reduced graphene oxide (rGO) by laser radiation is proposed. Molecular dynamics modeling by the real-time time-dependent density functional tight-binding (TD-DFTB) method made it possible to reveal the mechanism of field emission centers formation in carbon nanostructures layers. Laser radiation stimulates the formation of graphene-nanotube covalent contacts and also induces a dipole moment of hybrid nanostructures, which ensures their orientation along the force lines of the radiation field. The main mechanical and emission characteristics of the formed hybrid nanostructures were determined. By Raman spectroscopy, the effect of laser radiation energy on the defectiveness of all types of layers formed from nanostructures was determined. Laser exposure increased the hardness of all samples more than twice. Maximum hardness was obtained for hybrid nanostructure with a buffer layer (bl) of rGO and the main layer of SWCNT—rGO(bl)-SWCNT and was 54.4 GPa. In addition, the adhesion of rGO to the substrate and electron transport between the substrate and rGO(bl)-SWCNT increased. The rGO(bl)-SWCNT cathode with an area of ~1 mm2 showed a field emission current density of 562 mA/cm2 and stability for 9 h at a current of 1 mA. The developed technology for the formation of hybrid nanostructures can be used both to create high-performance and stable field emission cathodes and in other applications where nanomaterials coating with good adhesion, strength, and electrical conductivity is required.

Center for Mental Health Research and Innovation in Treatment Engagement and Service (MH-RITES Center) at the University of Houston

The Center for Mental Health Research and Innovation in Treatment Engagement and Service (MH-RITES Center) at the Graduate College of Social Work, University of Houston is an international multidisciplinary research center focused on improving treatment engagement and outcomes for those experiencing mental health concerns. Established in 2017, the mission of the MH-RITES Center is to drive empirically supported and evidence-based innovation that achieves optimal treatment access and engagement in mental health services by individuals and families who need them, specifically in historically marginalized communities. This article describes the history and guiding principles, organizational structure, funding sources, and physical resources of the MH-RITES Center while highlighting completed, ongoing, and future projects supporting the Center's mission.

A dual-emission Eu(Ⅲ) functionalized multi-ligand MOFs for wide range pH sensing

Reliable sensing of pH is very important in daily life. Herein, we construct a luminescent material Eu(BTA)@CPP3 for wide range pH sensing (1.19–13.90) with blue (∼430 nm) and red (∼613 nm) luminescent centers. First, amino-terephthalic acid (BDC-NH2) is partially replaced by 1,2,4-Benzenetricarboxylic acid (BTC) to construct multi-ligand UiO-66-NH2. Second, using the coordinating post-synthetic method, we successfully incorporate a red emission center (Eu-BTA, benzoyltrifluoroacetone) into the frameworks of multi-ligand UiO-66-NH2. To obtain the best luminescent material, all the parameters during the synthesis process are adjusted. Interestingly, Eu(BTA)@CPP3 shows three types of luminescent response modes in the process of pH sensing, including red emission quenching (1.19 < pH < 7.56), red emission quenching while blue emission enhancing (8.36 < pH < 12.04), and blue emission quenching (12.20 < pH < 13.98). The response mechanisms of each mode are discussed carefully. The luminescent color changes from red (natural and acidic solution) to blue (base solution), which can be identified by the naked eye. Furthermore, a luminescent pH test paper based on Eu(BTA)@CPP3 is prepared and is used to determine the pH practically.

A cognitive neurogenetic approach to uncovering the structure of executive functions

One central mission of cognitive neuroscience is to understand the ontology of complex cognitive functions. We addressed this question with a cognitive neurogenetic approach using a large-scale dataset of executive functions (EFs), whole-brain resting-state functional connectivity, and genetic polymorphisms. We found that the bifactor model with common and shifting-specific components not only was parsimonious but also showed maximal dissociations among the EF components at behavioral, neural, and genetic levels. In particular, the genes with enhanced expression in the middle frontal gyrus (MFG) and the subcallosal cingulate gyrus (SCG) showed enrichment for the common and shifting-specific component, respectively. Finally, High-dimensional mediation models further revealed that the functional connectivity patterns significantly mediated the genetic effect on the common EF component. Our study not only reveals insights into the ontology of EFs and their neurogenetic basis, but also provides useful tools to uncover the structure of complex constructs of human cognition.

Silicon quantum dots and MOFs hybrid multicolor fluorescent nanosensor for ultrasensitive and visual intelligent sensing of tetracycline

Metal-organic frameworks (MOFs) with multiple emission centers have recently bloomed out as attractive fluorescence (FL) sensors due to their high sensitivity and selectivity to multiple target species. Herein, a novel silicon quantum dots (SiQDs) hybride MOFs multicolor fluorescent nanosensor (SiQDs@MOF-Eu) was elaborately tailored for tetracycline detection, using in situ composition of SiQDs@MOF and further decoration of Eu3+ on its surface due to the coordination of free carboxyl groups and Eu3+. In this nanosensor, both the SiQDs with blue emission (λem=472 nm) and Eu3+ ions with potential red FL (λem=616 nm) can be served as specific recognition units of TC based on the inner filter effect (IFE) and the antenna effect, respectively. Upon the addition of TC, the emission intensity of the SiQDs decreased slowly while that of the Eu3+ ion increased significantly, accompanied by obvious blue-red color switching, resulting in ultrahigh sensitivity (detection limit 3.16 nM). Furthermore, real-time visual determination of TC in actual samples was successfully achieved. With the assistance of color scanning APP in smart phones, real-time intelligent determination of TC can be realized.

Flaring-associated Complex Dynamics in Two M Dwarfs Revealed by Fast, Time-resolved Spectroscopy

Habitability of an exoplanet is believed to be profoundly affected by activities of the host stars, although the related coronal mass ejections (CMEs) are still rarely detected in solar-like and late-type stars. We here report an observational study on the flares of two M dwarfs triggered by the high-cadence survey performed by the Ground-based Wide Angle Camera system. In both events, the fast, time-resolved spectroscopy enables us to identify symmetric broad Hα emission with not only a nearly zero bulk velocity, but also a large projected maximum velocity as high as ∼700–800 km s−1. This broadening could be resulted from either the Stark (pressure) effect or a flaring-associated CME at the stellar limb. In the context of the CME scenario, the CME mass is estimated to be ∼4 × 1018 and 2 × 1019 g. In addition, our spectral analysis reveals a temporal variation of the line center of the narrow Hα emission in both events. The variation amplitudes are at tens of kilometers per second, which could be ascribed to the chromospheric evaporation in one event, and to a binary scenario in the other one. With the total flaring energy determined from our photometric monitor, we show a reinforced trend in which the larger the flaring energy, the higher the CME mass is.

Effective Photosensitization in Excited-State Equilibrium: Brilliant Luminescence of TbIII Coordination Polymers Through Ancillary Ligand Modifications.

Molecular photosensitizers provide efficient light-absorbing abilities for photo-functional materials. Herein, effective photosensitization in excited-state equilibrium is demonstrated using five TbIII coordination polymers. The coordination polymers are composed of TbIII ions (emission center), hexafluoroacetylacetonato (photosensitizer ligands), and phosphine oxide-based bridges (ancillary ligands). The two types of ligand combinations induces a rigid coordination structure via intermolecular interactions, resulting in high thermal stability (with decomposition temperatures above 300 °C). Excited-triplet-state lifetimes of photosensitizer ligands (τ=120-1320 μs) are strongly dependent on the structure of the ancillary ligands. The photosensitizer with a long excited-triplet-state lifetime (τ≥1120 μs) controls the excited state equilibrium between the photosensitizer and TbIII , allowing the construction of TbIII coordination polymer with high TbIII emission quantum yield (≥70 %).

Preparation of lysosomal targeted fluorescent carbon dots and its applications in multi-color cell imaging and information encryption

In this study, carbon dots (CDs) were obtained by secondary hydrothermal method using ammonium citrate and folic acid as precursors. It had stable properties, small particle size and good water solubility, and its absolute quantum yield was up to 19.48%. Moreover, the emission centers of CDs shifted from green to yellow under different excitation and were successfully used for multi-color cell imaging and targeting of lysosomes. The CDs also showed different color in 254 nm and 365 nm UV light, which could be used to a fluorescent ink for information encryption. In addition, the fluorescence of CDs was quenched at pH 6–8 and showed a good linear relationship with a linear correlation coefficient of 0.9989, which had been implemented for the measurement of pH in tap water.

Tunable Luminescence of Sb3+ Doped 0D Cs4PbCl6 Nanocrystals from Three Distinct Emission Centers

AbstractMetal halide nanocrystals (NCs) with multiple emission centers are high‐potential luminescent materials used in versatile optoelectronic applications. However, technical challenges hinder the achievement of tunable emission bands in single‐component NCs. In this study, by elaborately using 0D Cs4PbCl6 to design Cs4PbCl6:Sb3+ NCs, multiple photoluminescence excited at specific energies without energy transfer occurred owing to the isolated and distinct centers in the 0D frame. The three emission centers at 368, 450 and 570 nm can be assigned to the 3P1 → 1S0 transition of Pb2+ ions, D‐state emission of Pb2+ ions, and 3P1 → 1S0 transition of Sb3+ ions, respectively. The emission colors of Cs4PbCl6:Sb3+ NCs can be easily tuned from ultraviolet to yellow by precisely modulating the excitation wavelength, and white‐light emission at 360 nm excitation with a color coordinate of (0.3026, 0.3264) is obtained owing to the simultaneous activation of Sb3+ ions and the D‐state. This study not only demonstrates a feasible scheme for designing multiple‐emitting metal halide NCs but also provides guidance for expansion of their applications in flexible optoelectronic devices.

Interstitial Li+ Occupancy Enabling Radiative/Nonradiative Transition Control toward Highly Efficient Cr3+-Based Near-Infrared Luminescence.

Highly efficient and stable broadband near-infrared (NIR) emission phosphors are crucial for the construction of next-generation smart lighting sources; however, the discovery of target phosphors remains a great challenge. Benefiting from the interstitial Li+ occupancy-induced relatively large distorted octahedral environment for Cr3+ and suppressed nonradiative relaxation of the emission centers, an NIR emission fluoride phosphor Na3GaF6:Cr3+,Li+ peaking at 758 nm with a high internal quantum efficiency of 95.8% and an external quantum efficiency of 38.3% is demonstrated. Moreover, it exhibits a good thermal stability (84.9%@150 °C of the integrated emission intensity at 25 °C) and excellent moisture resistance as well. A high-power light-emitting diode (LED) with a record watt-level NIR output (974.12 mW) and a photoelectric conversion efficiency of 20.9% is demonstrated by combining Na3GaF6:Cr3+,Li+ and a blue InGaN chip, and a special information encryption/decryption technology suitable for rapid and long-distance identification of machines is further presented based on this device. This study not only advances the development of efficient NIR emission phosphors for broadband NIR LEDs but also for NIR-related emerging applications and devices.

New Approach toward Dual-Emissive Organic-Inorganic Hybrids by Integrating Mn(II) and Cu(I) Emission Centers in Ionic Crystals.

Inorganic-organic hybrid luminescent materials have received great attention for their potential applications in a wide range of clean/renewable energy-related areas, including photovoltaics and solid-state lighting. Herein, we present a unique and general "Mn + Cu" approach by blending two earth-abundant luminogenic metals, manganese and copper, within a single ionic structure to construct a remarkable family of low-cost and multifunctional hybrid materials featuring dual emission, as well as triboluminescence and second-harmonic generation response. The novel hybrid materials are made of diphosphine dioxide-chelated [Mn(O∧O)3]2+ cations and various anionic [CuxIy](y-x)- clusters, ensuring manifestation of dual phosphorescence streamed from octahedral Mn2+ ions (605-648 nm) and iodocuprate anions (480-728 nm). Noteworthily, the relative ratio of the emission bands, and hence a resulting emission chromaticity, can be tuned in a wide range through modification of cluster [CuxIy](y-x)- modules. The structural diversity, enhanced robustness, and up to 100% luminescence quantum yield make the designed materials promising phosphors for lighting and sensing applications.

Red emission from clustered Mn2+ dopant in a tin-based perovskite semiconductor

Doping Mn2+ brings in new energy levels to a variety of II-VI family and perovskite semiconductors. Although the Mn2+ luminescence in most cases appears yellow to orange, photoexcitation of the tin-based perovskite material CsSn0.9Mn0.1Cl3 (CTMC) leads to an unusual red emission at 647 nm. Characterizations using time-resolved photoluminescence (PL) and electron paramagnetic resonance (EPR) indicate that most of the Mn2+ contents in CTMC are clustered like trimer chloromanganates, which accept photoexcitation energy from the perovskite matrix and acts as emission centers. These results are in sharp contrast from Mn2+-doped CsCaCl3 or CsPbCl3, where individual Mn2+ centers dominate the PL and EPR spectra. Our results provide a new approach to broadening the color range of Mn2+ emission in perovskite semiconductors.

Improved optical and electrical properties of Fe doped ZnO nanostructures facilely deposited by low-cost SILAR method for photosensor applications

The method of successive ionic layer adsorption and reaction (SILAR) was used to make Fe doped ZnO thin films by varying Fe concentrations (0, 2, 4, 6, and 8%). The prepared films were using the various analytical techniques such as X-ray diffraction (XRD), Field Emission scanning electron microscope (FESEM), Energy dispersive X-ray analysis (EDX), UV-Visible spectroscopy, photoluminescence (PL) spectroscopy and photosensing properties. XRD studies revealed the presence of Fe at the ZnO lattice, and all the prepared films exhibit hexagonal wurtzite structure. The SEM micrographs revealed the agglomerated particles over the surface of thin films. The UV–Vis studies showed that the optical band gap of undoped ZnO and 4% ZnO:Fe thin film were decreasing from 3.42 to 3.32 eV and started to increase up to 3.41 eV for further increase in Fe concentrations. The PL studies showed the emission centers at 393, 415, 435, 450, 480, and 525 nm. The 4% ZnO:Fe thin film has the maximum photoluminescence intensity due to the increasing Zn and O vacant sites, occupation of Fe2+ ions in the ZnO lattice revealed the enhancement of photosensing behavior. The photo detection properties and its significant parameters such as responsivity (R), External quantum efficiency (EQE) and detectivity (D*) of 4% ZnO:Fe thin film were determined and found to be as 1.96 × 10−1 AW−1, 45.83% and 4.95 × 1010 Jones respectively which is higher than other prepared sample films.

Structural Origin of Enhanced Circularly Polarized Luminescence in Hybrid Manganese Bromides

AbstractChiral hybrid metal halides with a high dissymmetry factor (glum) and a superior photoluminescence quantum yield (PLQY) are promising candidates for circularly polarized luminescence (CPL) light sources. Here, we report eight new chiral hybrid manganese halides, crystallizing in the non‐centrosymmetric space group P212121 and showing intense CPL emissions. Oppositely‐signed circular dichroism (CD) and CPL signals are detected according to the R‐ and S‐configurations of the chiral alkanolammonium cations. Time‐resolved PL spectra show long averaged decay lifetimes up to 1 ms for (R‐3‐quinuclidinol)MnBr3 (R‐1). The glum of polycrystalline samples for coordinated structures (23×10−3) is more than doubled compared with the non‐coordinated ones (8.5×10−3), due to the structural variations. R‐1 exhibit both a high glum and a high PLQY (50.2 %). The effective chirality transfer mechanism through coordination bonds, with strongly emissive MnII centers, enables a new class of high‐performance CPL materials.

Structural Origin of Enhanced Circularly Polarized Luminescence in Hybrid Manganese Bromides.

Chiral hybrid metal halides with a high dissymmetry factor (glum ) and a superior photoluminescence quantum yield (PLQY) are promising candidates for circularly polarized luminescence (CPL) light sources. Here, we report eight new chiral hybrid manganese halides, crystallizing in the non-centrosymmetric space group P21 21 21 and showing intense CPL emissions. Oppositely-signed circular dichroism (CD) and CPL signals are detected according to the R- and S-configurations of the chiral alkanolammonium cations. Time-resolved PL spectra show long averaged decay lifetimes up to 1 ms for (R-3-quinuclidinol)MnBr3 (R-1). The glum of polycrystalline samples for coordinated structures (23×10-3 ) is more than doubled compared with the non-coordinated ones (8.5×10-3 ), due to the structural variations. R-1 exhibit both a high glum and a high PLQY (50.2 %). The effective chirality transfer mechanism through coordination bonds, with strongly emissive MnII centers, enables a new class of high-performance CPL materials.

Exploring Potential Ways to Reduce the Carbon Emission Gap in an Urban Metabolic System: A Network Perspective.

To meet the global need for carbon neutrality, we must first understand the role of urban carbon metabolism. In this study, we developed a land–energy–carbon framework to model the spatial and temporal variation of carbon flows in Beijing from 1990 to 2018. Based on the changes in carbon sequestration and energy consumption, we used ecological network analysis to identify the critical paths for achieving carbon neutrality during land-use changes, thereby revealing possible decarbonization pathways to achieve carbon neutrality. By using GIS software, changes in the center of gravity for carbon flows were visualized in each period, and future urban construction scenarios were explored based on land-use policy. We found that the direct carbon emission peaked in 2010, mostly due to a growing area of transportation and industrial land. Total integrated flows through the network decreased at an average annual rate of 3.8%, and the change from cultivated land to the socioeconomic sectors and the paths between each socioeconomic component accounted for 29.5 and 31.7% of the integrated flows during the study period. The socioeconomic sectors as key nodes in the network should focus both on their scale expansion and on using cleaner energy to reduce carbon emissions. The center of gravity gradually moved southward, indicating that the new emission centers should seek a greener mixture of land use. Reducing carbon emission will strongly relied on transforming Beijing’s energy consumption structure and increasing green areas to improve carbon sinks. Our results provide insights into carbon flow paths that must be modified by implementing land-use policies to reduce carbon emission and produce a more sustainable urban metabolism.

Art, Science, and the Paradox of Knowledge: Decolonizing the European Avant-Garde

Art, Science, and the Paradox of Knowledge:Decolonizing the European Avant-Garde Thomas O. Haakenson (bio) The 2021 GSA Distinguished Lecture In the Thick of German Studies: The GSA Distinguished Lecture Series As part of the German Studies Association's cooperation with the Free University of Berlin's Program for Advanced German and European Studies, it was both an honor and a pleasure to launch our winter semester 2020/21 with the GSA Distinguished Lecture by Thomas O. Haakenson, Associate Professor in Critical and Visual Studies at the California College of the Arts on October 20, 2021. In his timely contribution, Art, Science, and the Paradox of Knowledge: Decolonizing the European Avantgarde, Professor Haakenson offered critical reflections on the European avant-garde's role in conceptualizing Western knowledge since the mid-nineteenth century. Haakenson's presentation was the ninth in our annual Distinguished Lecture Series. Initiated by GSA long-time Executive Director David Barclay, the series is designed to feature outstanding research by GSA members at Free University of Berlin and to strengthen ties between scholars working in these fields. We have had the privilege of hosting distinguished speakers on a broad array of subjects and it was David Barclay who delivered the first lecture on "Old Glory und Berliner Bär. Die USA und West-Berlin 1948–1994" in 2013. Suzanne Marchand followed in 2014 exploring "Orientalism and the Classical Tradition in Germany." For 2015, Joy Calico spoke on "Arnold Schoenberg's A Survivor from Warsaw in Postwar Europe: Musical Remigration and Holocaust Commemoration." Irene Kacandes took up another timely subject in 2016 and examined possibilities for "Memory Work for/ in the 21st Century." In her 2017 intervention "The Proletarian Prometheus," Sabine Hake applied the notion of cultural appropriation to examine the working class's use of bourgeois cultural tropes for political empowerment. Exploring the statue of a Hawaiian female deity in Berlin's ethnological collection, H. Glenn Penny engaged with the public controversies around ethnological museums in Europe in his 2018 contribution "Kihawahine: German Ethnology and its Histories of the World." Another compelling matter was taken up by Johannes von Moltke in 2019 who explored "The Meme is the Message: Alt-Right/Neue Rechte and the Political Affordances of Social Media." A strong case for considering Europe as a progressive alternative to Trump's America was made by historian Konrad H. Jarausch in his 2020 lecture "Embattled Europe: A Progressive Alternative." [End Page 329] The GSA Distinguished Lecture Series has given us much food for thought in the last decade and has served the program's central mission, to deepen the understanding of Germany and Europe in an exemplary way. Karin Goihl, Berlin Program Academic Coordinator, Free University of Berlin [End Page 330] The Wonderful World of Words My aunt Hiede Miyazaki was born in Kumamoto, Japan, on March 10, 1931. She was an excellent student, preparing at the end of World War II for college when her father passed away from cancer (Figure 1). At seventeen years old, she became the family's primary provider, often working several jobs and going hungry to support her mother, four siblings, and herself. Eventually, Hiede's English-language skills led to a position with the US Armed Forces at Camp Kumamoto and later on at both Itazuke Air Base in Fukuoka and Johnson Air Base in Tokyo. She continued her creative practice at the same time and became a skilled, much-sought-after Japanese Sumi-E artist, exhibiting widely and teaching classes in mainland Japan, the United States, Canada, and Germany. In the early 1960s, my Aunt Hiede met, and shortly thereafter married, my Uncle Gene. They were together for almost fifty-eight years. My first encounter with Germany, with German culture and the German language, was made possible thanks to my Aunt Hiede. In 1987, when I was fifteen years old, I flew to Germany to visit her and my Uncle Gene, who at the time lived in a small town in southern Germany near a US military base. I traveled alone transatlantically, with no German language skills and, quite frankly, a rather limited grasp of the English language as well. It was only my second time aboard an...

Ultrafast synthesized monometallic nanohybrids as an efficient quencher and recognition antenna of upconversion nanoparticles for the detection of xanthine with enhanced sensitivity and selectivity

Upconversion nanoparticles (UCNPs) have shown great promise in bioanalytical applications owing to their excellent optical properties. Generally, most analytical applications are based on the fluorescence resonance energy transfer (FRET) principle to quench the fluorescence of UCNPs. However, each UCNP contains thousands of emission center ions, and most of them exceed the FRET critical distance, which hinders FRET efficiency and leads to a low signal-to-background ratio (SBR). Herein, a novel nanoprobe for the detection of Xanthine (XA) based on inner filter effects (IFE) and cascade signal amplification strategy was constructed by decorating UCNP with trypsin-chymotrypsin-stabilized gold nanoparticles-gold nanoclusters (Try-chy-AuNPs-AuNCs) monometallic nanohybrids. The Try-chy-AuNPs-AuNCs prepared by ultrafast (3 min) and green synthesis method have efficient upconversion fluorescence quenching ability (the quenching efficiency up to 90.9%), which can effectively improve the SBR of the probe, so as to improve the sensitivity. In addition, the Try-chy-AuNPs-AuNCs have a unique spatial structure, which can effectively prevent the interaction between large-size biothiol (glutathione) and the probe, thus improving its selectivity. Besides, combined with the excellent optical performance of UCNPs and cascaded signal amplification strategy, the sensitivity of the probe can be further improved. Under the optimized conditions, the linear response range of the probe was obtained from 0.05 to 50 μM, 0.06–80 μM and with the low detection limit of 22.6 nM and 26.3 nM for H2O2 and XA, respectively. Meanwhile, the developed method has been further applied to the detection of XA in human serum with satisfactory results.

Monosystem Discriminative Sensor toward Inorganic Anions via Incorporating Three Different Luminescent Channels in Metal-Organic Frameworks.

Because there are great demands of distinguishing multiple chemically similar analytes, chemical sensors for multivariate analyses have been developed rapidly in the past few decades. However, designing luminescent discriminative sensors based on a monosystem has been a challenge until now. In this work, we first develop a triemitting luminescent discriminative platform named RGB@TLU-2 with three different emission centers: blue-emitting center (BDC-NH2), green-emitting (Tb@BDC-SO3-), and red-emitting center (rhodamine B, RhB). The different luminescent mechanisms (ligand emission, LMET emission, guest emission) in these emission centers endow RGB@TLU-2 with high cross-reactivity, which is essential for discriminating applications. To balance the three luminescent centers, all variables in the synthesis process are optimized carefully. Surprisingly, the RGB@TLU-2 shows a variety of luminescent response patterns when immersed into 12 inorganic anions. Two unsupervised multidimensional analysis methods, (principal component analysis and hierarchical cluster analysis), are used to explore the relationship between these anions. On the basis of the luminescent response of analytes, 5 response modes are obtained and 12 inorganic anions are classified into 6 groups. The sensing mechanisms are discussed in detail. Detection limits of typical anions Cr2O72-, PO43-, ClO-, and NO2- are calculated as 2.895 × 10-8, 6.353 × 10-6, 1.134 × 10-5, and 4.56 × 10-4 mol/L, respectively. Furthermore, the RGB@TLU-2 also shows the ability to distinguish 4 (Fe3+, Fe2+, Cu2+ and Cr3+) of 12 metal ions and 3 (Trp, Pro, and Arg) of 11 amino acids.