Absolute Quantum Yield Research Articles

Molecular Engineering of Xanthene Dyes with 3D Multimodal-Imaging Ability to Guide Photothermal Therapy.

Phototheranostics integrates light-based diagnostic techniques with therapeutic interventions, offering a non-invasive, precise, and swift approach for both disease detection and treatment. The efficacy of this approach hinges on the multimodal imaging potential and photothermal conversion efficiency (PCE) of phototheranostic agents (PTAs). Despite the promise, crafting multifunctional phototheranostic organic small molecules brims with challenges. In this research, four innovative xanthene-derived PTAs are synthesized by fine-tuning the donor-π-acceptor (D-π-A) system to strike a balance between radiative and nonradiative decay. The inherent robust photostability and intense fluorescence of the traditional xanthene core are preserved, meanwhile the addition of highly electron-withdrawing groups boosts the non-radiative decay rate to enhance PCE and photoacoustic imaging capabilities. Remarkably, one of the PTAs, DMBA, demonstrates an exceptional absolute fluorescence quantum yield of 2.46% in PBS, and when encapsulated into nanoparticles, it achieves a high PCE of 79.5%. Consequently, DMBA nanoparticles (DMBA-NPs) are effectively employed in fluorescence, 3D photoacoustic, and photothermal imaging-guiding tumor photothermal therapy. This represents the first instance of a multimodal phototheranostic xanthene agent achieving synergistic fluorescence and photoacoustic imaging for diagnostic purposes. Furthermore, this work paves the way for leveraging xanthene fluorophores as versatile tools in the development of multifunctional reagents.

Aryl/fluoroaryl-substituted triphenylene discotic liquid crystals: Synthesis, mesomorphism, and photophysical properties

Fluorine aromatic hydrocarbons are ubiquitous optoelectronic functional materials and their efficient synthetic methods are still the subject of rapid, ongoing development. Here, several aryl- and fluoroaryl-substituted triphenylenes (Ar-TP/FAr-TP) were synthesized via either Suzuki-Miyaura cross-coupling or aromatic nucleophilic substitution (SNAr) of perfluoroarenes, respectively, starting indifferently from 2-bromo-3,6,7,10,11-pentakis(hexyloxy)triphenylene (Br-TP). These compounds possess very high thermal stability with initial decomposition temperature over 300 °C, as measured by thermal gravimetric analysis (TGA). Differential scanning calorimetry (DSC), polarized optical microscopy (POM), and small/wide angle X-ray scattering (S/WAXS) revealed that they all self-organize into hexagonal columnar (Colhex) mesophase over broad temperature ranges, occurring at room temperature for some of them, with higher stability than the archetypical 2,3,6,7,10,11-hexakis(hexyloxy)triphenylene parent compound. Under the combined influence of the conjugated π-system and core-side arm distortion, the clearing temperatures and mesophase ranges increase from phenyl- (P-TP), naphthyl- (N-TP), to biphenyl-triphenylene (BP-TP). The number of fluorine atoms on the side fluoroaryl group also impacts the columnar mesomorphism: the more fluorine atoms, the higher the clearing temperatures and the wider the Colhex phase ranges, concomitantly with increasing arene-fluorarene intermolecular interactions. In addition, these compounds show blue-violet photoluminescence in solution: the largest fluorescent absolute quantum yield is measured for BP-TP (45 %), while the smallest is for 7FN-TP (10 %). Perfluoroaryls tend to lower the LUMO, which results in fluorescence red-shift. The arene-perfluoroarene polar-π interactions improve the physical properties of these FAr-TP discotic liquid crystals.

Construction of 2-azidacetic acid functionalized high-crystallinity fluorescent covalent organic framework: Applications in mitoxantrone and Fe3+ sensing and adsorption

Due to the dual functions of fluorescence detection and adsorption, fluorescent covalent organic frameworks (COFs) have attracted significant attention. However, common fluorescent COFs often exhibit unsatisfactory fluorescence properties and selectivity, coupled with poor solution dispersibility, which limit their effectiveness in detection and adsorption applications. In response, a novel post-modified fluorescent COF (named AZC-COF) was synthesized by connecting a fluorescent COF (COF-TB) with 2-azidacetic acid through a copper-catalyzed aide-alkyne cycloaddition (CuAAC) reaction. AZC-COF demonstrated excellent solution dispersibility and robust green fluorescence, boasting an absolute fluorescence quantum yield (QY) of 7.58%, which was 13.5 times higher than that of COF-TB. Furthermore, leveraging the active carboxylic acid and triazole sites, AZC-COF exhibited remarkable binding abilities for mitoxantrone (MIX) and Fe3+, enabling sensitive detection and efficient adsorption of them. In contrast, due to the absence of these functional sites, COF-TB showed poor detection and enrichment capabilities for MIX and Fe3+. The impressive detection and adsorption efficiencies of MIX and Fe3+ in environmental water, aquatic organism (fish) and plasma samples underscore the potential of AZC-COF as a detection-adsorption platform. Additionally, AZC-COF demonstrated low toxicity and hemolytic activity, alongside promising potential for cell imaging and detection of MIX and Fe3+, highlighting its considerable application prospect in biological systems.

Enhanced hypersensitive (5D0→7F2) transition characteristics of Eu3+ doped β-Ga2O3 microrods

Exploring and realizing the luminescence characteristics of rare earth metal (RE) ions doped gallium oxide (Ga2O3) is crucial for developing optoelectronic device applications. The current research used the solid-state reaction approach to synthesize Ga2O3 microrods doped with various europium (Eu3+) concentrations (0.1, 0.2, 0.3, 0.5, 0.75, and 1 mol). X-ray diffraction (XRD) and Raman spectral analyses confirm the monoclinic structure of β-Ga2O3. The intensity of the Raman phonon modes decreased and a peak shift was observed for Eu:β-Ga2O3. The electron microscopy (SEM, TEM) images depicted a nearly uniform distribution of microrods for undoped and Eu:β-Ga2O3 samples. The interplanar distance (d = 0.290 nm, 0.561 nm, and 0.433 nm), from HR-TEM images, corresponding to (0 0 4), (1 0 0), and (1 0 2) crystallographic orientations confirm the monoclinic structure of β-Ga2O3. The elemental mapping images showed a nearly homogeneous Ga, O, and Eu distribution. The UV–visible diffuse reflectance spectroscopy (UV-DRS) showed a notable reduction in the bandgap as the Eu3+ concentration increased. The emission spectra of Eu: β-Ga2O3 microrods showed a narrow red emission at 612 nm (5D0 → 7F2), which relates to the 5D0 → 7Fj (j = 0, 1, 2, 3) energy level arising from an intra-4f transition of Eu3+ ions upon 394 and 465 nm excitation. The red emission was found to increase with Eu content up to 0.5 mol.%. A quenching of emission due to the multipole–multipole interactions was obtained beyond 0.5 mol.% of Eu. The absolute quantum yield (η) calculated for Eu: β-Ga2O3 (0.5 mol.%) was 3.82 %. The luminescence decay curve using the bi-exponential fit and the average lifetime (τ) of the Eu: β-Ga2O3 (0.5 mol.%) was found to be ∼0.172 ms. CIE chromaticity and correlated color temperature analyses of Eu:β-Ga2O3 microrods yielded a red emission with a superior color purity (93 %). The obtained results suggest that Eu:β-Ga2O3 (0.5 wt.%) microrods could be one of the potential candidates for red light sources.

L-cysteine capped MoS2 QDs for dual-channel imaging and superior Fe3+ ion sensing in biological systems.

MoS2 quantum dots (MQDs) with an average size of 1.9 ± 0.7 nm were synthesized using a microwave-assisted method. Absorbance studies confirmed characteristic transitions of MoS2, with absorption humps at 260-280 nm and 300-330 nm, and a band gap of 3.6 ± 0.1 eV. Fluorescence emission studies showed dominant blue and some green emissions under 315 nm excitation, with an absolute quantum yield of ∼9%. The MQDs exhibited fluorescence stability over time after repeated quenching cycles across various pH and media systems. In vitro toxicity tests indicated cytocompatibility, with around 80% cell survival at 1000 mg L-1. Confocal imaging demonstrated significant uptake and vibrant fluorescence in cancerous and non-cancerous cell lines. The MQDs showed strong selectivity towards Fe3+ ions, with a detection limit of 27.61 ± 0.25 nM. Recovery rates for Fe3+ in phosphate buffer saline (PBS) and simulated body fluid (SBF) systems were >97% and >98%, respectively, with a relative standard deviation (RSD) within 3%, indicating precision. These findings suggest that MQDs have high potential for diagnostic applications involving Fe3+ detection due to their fluorescence stability, robustness, enhanced cell viability, and dual-channel imaging properties.

A smartphone-integrated ratiometric fluorescent sensor for ascorbic acid determination using microplasma-enabled carbon dots and rhodamine B

A switchable ratiometric fluorescent smartphone-assisted sensing platform based on nitrogen-doped carbon dots (N-CDs) and Rhodamine B was fabricated for the determination of the ascorbic acid (AA) content in fruits by quenching the fluorescence of N-CDs with Hg2+ (turn-off) and recovering with AA (turn-on). The blue-emission N-CDs was synthesized by liquid dielectric barrier discharge microplasma with an average size of 3.65 nm and an absolute quantum yield of 18 % (excited at 345 nm). In addition, the fluorescence color was converted to RGB values, enabling visual and quantitative determination of AA. Under optimal parameters, the linear ranges for detecting AA were found to be 3–170 μM and 5–170 μM for fluorescence spectrometer and smartphone sensing platform. The detection limits were 0.98 μM and 2.90 μM, respectively. Furthermore, the satisfactory recoveries in fruits were obtained by RF probe and smartphone platform. This smartphone-assisted platform will facilitate sensitive and visual determination for AA.

Boron cluster-based TADF emitter via through-space charge transfer enabling efficient orange-red electroluminescence

Thermally activated delayed fluorescence (TADF) materials driven by a through-space charge transfer (TSCT) mechanism have garnered wide interest. However, access of TSCT-TADF molecules with long-wavelength emission remains a formidable challenge. In this study, we introduce a novel V-type D-A-D-A' emitter, Trz-mCzCbCz, by using a carborane scaffold. This design strategically incorporates carbazole (Cz) and 2,4,6-triphenyl-1,3,5-triazine (Trz) as donor and acceptor moieties, respectively. Theoretical calculations alongside experimental validations affirm the typical TSCT-TADF characteristics of this luminogen. Owing to the unique structural and electronic attributes of carboranes, Trz-mCzCbCz exhibits an orange-red emission, markedly diverging from the traditional blue-to-green emissions observed in classical Cz and Trz-based TADF molecules. Moreover, bright emission in aggregates was observed for Trz-mCzCbCz with absolute photoluminescence quantum yield (PLQY) of up to 88.8%. As such, we have successfully fabricated five organic light-emitting diodes (OLEDs) by utilizing Trz-mCzCbCz as the emitting layer. It is important to note that both the reverse intersystem crossing process and the TADF properties are profoundly influenced by host materials. The fabricated OLED devices reached a maximum external quantum efficiency (EQE) of 12.7%, with an emission peak at 592 nm. This represents the highest recorded efficiency for TSCT-TADF OLEDs employing carborane derivatives as emitting layers.

Synthesis and photoluminescent spectroscopic analysis of lanthanum (III) coordinated with 1,10-Phenanthroline: A study of its thermally stable behavior

A blue-emitting phosphor designed by lanthanum (III) coordinated with two 1,10-Phenanthroline and three nitrate ligands, [La(Phen)2(NO3)3], was obtained by an effective and simple precipitation method. Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffraction (PXRD) revealed the coordination modes in the compound and the chemical structure, crystallizing in a monoclinic system in the C2/c space group. The luminescence properties, absolute quantum yield (ϕ), and luminescence lifetime decay (τ) were determined by photoluminescence spectroscopy. Under a 350 nm excitation, the sample presents three emission bands corresponding to the π* → π transitions belonging to the organic ligand. The luminescence lifetime (τ) was determined through a monoexponentially fit, obtaining a value of 5616 ns. The [La(Phen)2(NO3)3] complex exhibits an absolute quantum yield of 3 % with the same excitation conditions. In addition, the photometric analysis shows that the luminescent response to a 350 nm excitation is that of a blue-emitting high-purity phosphor with 96 % and chromatic coordinates of 0.15, 0.05. The temperature-dependent luminescence properties revealed considerable thermal stability in the 20–150 °C range with a signal loss of 47 % and an activation energy of thermal quenching (ΔE) of 0.13 eV, the first value reported for a lanthanum complex based on 1,10-Phenanthroline.

Fluorescent and colorimetric dual-mode detection of Cu2+ based on carbon dots.

A fluorescent and colorimetric dual-mode strategy based on carbon dots (CDs) was rationally designed for sensitive determination of Cu2+. Green fluorescent CDs with high absolute quantum yield of 72.9% were synthesized by facile one-step hydrothermal treatment of triethylenetetramine and Rose Bengal. Cu2+ could trigger the oxidative and chromogenic reaction of p-phenylenediamine (PPD) to generate chromogenic PPDox, accompanied by the fluorescence quenching of the CDs. The quenching mechanism was identified as the inner filter effect between PPDox and CDs. Therefore, a colorimetric/fluorescent dual-mode detection method for Cu2+ recognition was constructed. The limits of detection for Cu2+ were 4.14μM and 1.28μM for colorimetric and fluorescent mode, respectively. In addition, this method had achieved satisfactory results in the detection of Cu2+ in real serum samples.

Developing an off-on fluorescence sensor based on red copper nanoclusters wrapped by sulfhydryl and polymer double ligands for sensitive detection of N-acetyl-L-cysteine

N-acetyl-L-cysteine (NAC) as a class of thiols is commonly used in the treatment of lung diseases, detoxification and prevention of liver damage. In this paper, 4-mercaptobenzoic acid (4-MBA) coated and polyvinylpyrrolidone (PVP) attached copper nanoclusters (4-MBA@PVP-CuNCs) were successfully synthesized using a simple one-pot method with an absolute quantum yield of 10.98 %, and its synthetic conditions (like effects of single/double ligands and temperature) were studied intensively. Then Hg2+ could quench the fluorescence of the 4-MBA@PVP-CuNCs and its fluorescence was restored with the addition of NAC. Based on the above principles, an off–on switching system was established to detect NAC. That is, the 4-MBA@PVP-CuNCs-Hg probe was prepared by adding Hg2+ to switch off the fluorescence of the CuNCs by static quenching, and then NAC was added to switch on the fluorescence of the probe based on the chelation of NAC and Hg2+. Moreover, the effects of metal ion types and mercury ion doses for the probe construction were also further discussed. The method showed excellent linearity in the range of 0.05–1.25 µM and low detection limit of 16 nM. Meanwhile, good recoveries in real urine, tablets and pellets were observed, which proved the reliability of the method and provided a convenient, fast and sensitive method for NAC detection.

Chlorine passivation of PbS quantum dots in all solid glass matrix for high efficiency luminescence

Lead sulfide quantum dots (PbS QDs) show great potential application in near infrared range, and incorporation of PbS QDs into all solid glass matrix improves both their chemical and thermal stabilities as well as the shaping ability. However, the incorporation of PbS QDs into all solid glass matrix makes it difficult to modify their surface, resulting in the relatively low absolute photoluminescence quantum yield (PL QY) caused by the surface defects. Here, PbS QDs with tunable photoluminescence band in near-infrared range in silicate glasses were prepared by melting-quenching method. By addition of chloride and forming PbClx shell around PbS QDs in glass, defects induced by surficial lead ions of above PbS QDs can be effectively passivated, reducing subsequent trapping of photo-generated electrons accordingly. PL QY of PbS QDs inbuilt glasses is enhanced eventually and achieved as high as 49.3 %. Furthermore, thermo- and photo-stabilities of PbS QDs in glass are greatly improved compared with those without surface chlorine passivation. These high performance PbS QDs embedded glasses with excellent stability show significant potential in light-emitting diodes, lasers and fiber amplifiers in near-infrared range.

Fabrication of ZnO-quantum dot hybrid nanocomposites with enhanced light scattering and emission characteristics for micro LED display applications

Herein, a facile method is reported to fabricate a color conversion layer comprised of zinc oxide nanoparticles (ZnO NPs) and quantum dots (QDs) for micro-light emitting diode (μ-LED) displays. Further, 11-mercaptoundecanoic acid (MUA)-treated ZnO NPs (ZnO@MUA NPs) are synthesized via a high-energy ball milling method, which bypasses the need for complex synthesis processes and enables functional groups to attach to the surface, thereby facilitating the formation of ZnO@MUA NPs-QD hybrid composites (ZQCs). The particle size, surface characteristics, elemental composition, and binding energy are analyzed to elucidate the reaction mechanism and to confirm that the fabricated ZQC exhibits a chemically bonded structure. To ascertain the optimal molar concentration for incorporating the QDs, parameters such as QD bonding efficiency, quantity of bonded QDs, interparticle distance, and absolute photoluminescence quantum yield (PLQY) are evaluated as functions of molar concentration. As a result, the optimal molar concentration is found to be 1930 nM, giving a bonding efficiency of 96.8 %, along with the bonded QDs of 1.51 × 1011 per a unit area of 1 mm2 of ZnO NPs and a PLQY of 64.8 %. Furthermore, comprehensive optical analyses are performed to assess the potential of the ZQC as a color conversion material for μ-LED displays, in comparison to the use of pristine QDs and silica NP-QD composites.

Nitrated benzothiadiazole-based D-A electrochromic polymers with tunable spectral properties

Nitrated benzothiadiazole (BT) is the promising acceptor units in constructing D-A-D electrochromic polymers, but its researches in the electrochromic field was very limited so far. In this work, four kinds of nitrated polymer precursors (Th-NO2-BT, EDOT-NO2-BT, Th-2NO2-BT, and EDOT-2NO2-BT) were synthesized by Stille coupling reaction with EDOT and thiophene units as the end groups (electron donor units) and mono-nitrated benzothiadiazole and di-nitrated benzothiadiazole as the core groups (electron acceptor units). The chemical structure and optical properties of the precursor were investigated by means of 1H NMR, UV–vis absorption and fluorescence spectra; the corresponding mono-nitrated polymer films were obtained in CH2Cl2-Bu4NPF6 system by electrochemical deposition method. The optical band gap of di-nitrated polymer precursor is obviously larger than the corresponding mono-nitrated polymer precursor (both ultraviolet and fluorescence spectra are obviously blue-shifted), accompanied with the obvious increased initial oxidation potential. Due to the fluorescence quenching effect of -NO2 group, their absolute quantum yields are all very low (0.0006–0.015). The spectroelectrochemistry and electrochromic kinetics of mono-nitrated polymer films (P(Th-NO2-BT) and P(EDOT-NO2-BT)) were studied. It was found that P(EDOT-NO2-BT) can show better electrochromic performance than P(Th-NO2-BT), with dark green in the neutral state and more obvious electrochromic performance in the near-infrared region (optical contrast: 38.4 %, coloration efficiency: 129.1 cm2/C, and fast response time: 1.4 s). This systematically study about the effects of nitro substitution effect on the properties of D-A electrochromic polymers, which will further expand the selection of the new acceptor units and the application prospect of nitrated electrochromic materials.

Polymerized Carbon Dots with Broad Emission and Suppressed Aggregation‐Caused Quenching Effect Toward Electroluminescent White Light‐Emitting Diodes

AbstractCarbon dots (CDs) possess intrinsically broad emission spectra, making them suitable for modulating high‐quality white light‐emitting diodes (WLEDs). However, the chief technical challenge in applying CDs to WLEDs is the aggregation‐caused quenching (ACQ) effect. A common solution is polymer post‐modification on the surface of CDs, which is a low‐yield, hard‐to‐purified, and complicated process. Herein, polymerized CDs with broad emission (full width at half maxima, FWHM = 187 nm) are synthesized via a one‐step solvothermal method. The obtained polymerized CDs display excellent solution‐processed and film‐forming capabilities, with absolute photoluminescence quantum yield as high as 4.7% in thin film state, creating a firm foundation for assembling solution‐processed WLEDs. Moreover, the polymerization steps of CDs are analyzed and described in detail. The polymer chains prevent ACQ and create new energy levels, resulting in the broad emission of CDs in an aggregated state. Subsequently, WLEDs are fabricated using polymerized CDs as the single active emitting material. The optimal device achieves the maximum brightness of 337.50 cd m−2 and FWHM of 242 nm, covering nearly the entire visible spectral window. The results present a new approach to obtaining polymerized CDs and further fabricating WLED with a straightforward, cost‐effective method.

Facile Light-Driven Synthesis of Highly Luminous Sulfur Quantum Dots for Fluorescence Sensing and Cell Imaging.

Sulfur quantum dots (SQDs) are emerging fluorescent nanomaterials, whereas most of the methods for synthesizing SQDs are limited to thermal synthesis. In this study, we report the first case of a light-driven strategy for facile synthesis of SQDs and further applied the SQDs for fluorescence cell imaging. The light-driven synthesis strategy only utilized Na2S as the sulfur source and nano-TiO2 as the photosensitizer. Under ultraviolet illumination, the nano-TiO2 photosensitizer generated a large number of •O2- and •OH to oxidize S2- to Sx2- and further to elemental sulfur, which could be obtained as monodispersed SQDs after etching by H2O2. The prepared SQDs exhibit excellent tunable photoluminescence properties, superior stability, and a uniform small size, with particle diameters in the range of 0.5-4 nm, and the fluorescence absolute quantum yield is as high as 27.8%. Meanwhile, the prepared SQDs also exhibited extreme biocompatibility and stability, and we further applied it for intracellular imaging and Hg2+ sensing with satisfactory results. In comparison to the widely reported thermal synthesis, the light-driven synthesis method is greener and simpler, opening a new way for the preparation of biocompatible SQDs.

Green Fluorescent Carbon Dots with Critically Controlled Surface States: Make Silk Shine via Feeding Silkworms.

Feeding silkworms with functional materials as additives to produce naturally modified silk is a facile, diverse, controllable, and environmentally friendly method with a low cost of time and investment. Among various additives, carbon dots (CDs) show unique advantages due to their excellent biocompatibility and fluorescence stability. Here, a new type of green fluorescent carbon dots (G-CDs) is synthesized with a high oil-water partition ratio of 147, a low isoelectric point of 5.16, an absolute quantum yield of 71%, and critically controlled surface states. After feeding with G-CDs, the silkworms weave light yellow cocoons whose green fluorescence is visible to the naked eye under UV light. The luminous silk is sewn onto the cloth to create striking patterns with beautiful fluorescence. Such G-CDs have no adverse effect on the survival rate and the life cycle of silkworms and enable their whole bodies to glow under UV light. Based on the strong fluorescence, chemical stability, and biological safety, G-CDs are found in the digestive tracts, silk glands, feces, cocoons, and even moth bodies. G-CDs accumulate in the posterior silk glands where fibroin protein is secreted, indicating its stronger combination with fibroin than sericin, which meets the requirements for practical applications.

Studies of Anticancer Activities In Vitro and In Vivo for Butyltin(IV)-Iridium(III) Imidazole-Phenanthroline Complexes with Aggregation-Induced Emission Properties.

Organotin(IV) and iridium(III) complexes have shown good application potential in the field of anticancer; however, the aggregation-caused quenching (ACQ) effect induced by high concentration or dose has limited the research on their targeting and anticancer mechanism. Then, a series of aggregation-induced emission (AIE)-activated butyltin(IV)-iridium(III) imidazole-phenanthroline complexes were prepared in this study. Complexes exhibited significant fluorescence improvement in the aggregated state because of the restricted intramolecular rotation (RIR), accompanied by an absolute fluorescence quantum yield of up to 29.2% (IrSn9). Complexes demonstrated potential in vitro antiproliferative and antimigration activity against A549 cells, following a lysosomal-mitochondrial apoptotic pathway. Nude mouse models further confirmed that complexes had favorable in vivo antitumor and antimigration activity in comparison to cisplatin. Therefore, butyltin(IV)-iridium(III) imidazole-phenanthroline complexes possess the potential as potential substitutes for platinum-based drugs.

Investigation of column purified dye derived carbon nanomaterials for security printing and supercapacitor applications

Literature evidence reveals versatile applications of carbon dots (CDs), but generally mixtures of various types of carbon nanomaterials, molecular intermediates as well as side products are obtained upon hydrothermal treatment of the precursor material. This demands isolation of pure components and their complete characterization before these nano carbonaceous materials are chosen for suitable applications. In the present study, perylenetetracarboxylic dianhydride (PTCDA) is subjected to hydrothermal treatment and the mother liquor obtained is separated using column chromatography technique using dichloromethane-methanol solvent system to isolate fractions of various fluorescent carbonaceous nanostructures. The TEM imaging of nano carbonaceous particles of all five fractions indicated that the first and third fractions were composed of nanoribbons, while the latter two fractions largely contained quasi-spherical nanoparticles of both lesser (carbon quantum dots) and greater (carbon nanodots) than 10 nm dimensions. The XPS results of all the fractions suggested separation based on polarity difference. The ID/IG ratios obtained from Raman spectra implied the presence of several defects on the CDs. The time resolved fluorescence spectra of third, fourth and fifth fractions revealed mono-exponential decay of fluorophores with excitation independent average lifetime values. The fifth fraction exhibited good biocompatibility and the highest absolute fluorescence quantum yield of 58.47 % among all the isolated samples. As these CDs displayed a remarkable rise in the quantum yield to 88.60 % when dispersed in water, a water-based flexo-ink was formulated. The photostable pale yellow flexo print proofs obtained on UV dull paper exhibited a green fluorescence under 365 nm illumination, whereas a yellow glow when shined with blue light, which can serve as an authentication feature for security documents and currency notes. Moreover, as the third fraction constitutes mainly of carbon nanoribbons (CNRs), an optimized polymer electrolyte was prepared along with sodium alginate (SA), and MgCl2 to understand their potential use in energy storage application. A supercapacitor was fabricated and tested for its electrochemical performance such as cyclic voltammtery (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge (GCD). An enhanced current window was observed in the CV of SA/CNRs compared to pure SA and SA/CNRs/Mg films, which indicated a structural interaction of CNRs with SA. The conductivity of SA/CNRs/Mg was lesser than SA/CNRs in EIS studies due to the presence of Mg ions, while pure SA showed lesser conductivity. The dual ionic interaction of Na and Mg along with enhanced structural stability due to doped CNRs favors its convenient supercapacitor application. The fabricated eco-friendly supercapacitor showed a specific capacitance of 84 F/g. The GCD of the device displayed pseudocapacitance behaviour and was quite stable for 2000 cycles with coulombic efficiency of 96 %.

Ultra Broad‐Band Excitable Organic–Inorganic Copper(I) Halides: Large‐Scale Synthesis, Outstanding Stability, and Highly Efficient White Light‐Emitting Diodes Application

AbstractOrganic–inorganic copper(I) halides (OICHs) have recently attracted great attentions for their unique optoelectronic properties. However, most of them have poor stability and narrow excitation in UV region, which seriously hinder their applications in efficient white light‐emitting diodes (WLEDs). Herein, 0D (C19H18P)2Cu4I6 with super broad‐band excitation (300–500 nm) and yellow emission with the absolute photoluminescence quantum yield of 87.4% is synthesized in a quantity of gram scale. Specifically, (C19H18P)2Cu4I6 possesses exceptional thermal‐, photo‐, air‐stability, and can maintain efficient emission even if soaked in water, ethyl acetate, and isopropanol over 30 days. WLEDs with remarkable color stability under various driven currents are fabricated using 450, 400, 365, and 310 nm LED chips. The ideal WLEDs based on single (C19H18P)2Cu4I6 by 450 nm LED chip presents high color rendering index of 86.7, and outstanding luminous efficiency of 90 lm W−1. To the best of the knowledge, this is the highest value that is achieved based on single‐component OICHs using blue light chip. This work not only promotes the prospect of OICHs in WLEDs but also significantly broadens their application in special lighting fields, such as underwater illumination.

Fluorescent detection of nitrofuran antibiotics with a recordly brilliant covalent organic framework

The antibiotic residues in the water have serious effects on ecological security despite its importance for human in countering bacterium infection. The effective detection of antibiotics in drinking water could give fast, accurate diagnostic evidence, and help prevent antibiotic contamination. Herein, we report a novel fluorescent covalent organic framework (TAPA-BTD-COF) for the highly effective detection of nitrofuran antibiotics. TAPA-BTD-COF is synthesized by condensation of benzothiadiazole and tris(4-aminophenyl) amine. It exhibits an extremely strong blue fluorescence and has a record absolute fluorescence quantum yield (PLQY) in organic solvents. Besides, the COF had strong light-absorption. These properties rendered it very brilliant fluorescence, which is convenient for achieving fluorescent sensing applications. TAPA-BTD-COF exhibited efficient turn-off fluorescence response to four different kinds of nitrofuran antibiotics. Moreover, TAPA-BTD-COF fluorescence sensor exhibited a fast response to nitrofuran antibiotics with a wide detection range and linear relationship, with satisfactory LOD of 0.10 μM. And the rapid response can be achieved within 10 s. Real samples of three kinds of different water and three different kinds of meat were analyzed by adding standard recovery test. The experimental results indicated that the fluorescent sensor exhibited paralleled excellent recovery in comparison with ISO standard liquid-chromatography method. Besides, IR and XPS experiments were conducted to investigate the underlying mechanism for this efficient fluorescence sensing. The results revealed a static quenching mechanism by forming electron donor–acceptor adducts between COF sensor electron-rich triphenylamine group and nitrofuran antibiotics electron-deficient nitrofuran groups.