Blue Emission Research Articles

Structural consideration on Eu2+ distribution inside glaserite-type Na(Ba, Sr)PO4: Eu2+ phosphor: high-intensity and broadband emission consisting of three overlapping Eu2+ emission bands

Glaserite-type NaBaPO4: Eu2+ phosphor has attracted considerable attention because of the intense blue emission. Although this emission was discussed under the assumption that Eu2+ ions were distributed only in A- and B-sites of the crystal structure, this assumption has proved inconsistent with previous results and hindered the quantitative evaluation of the emission. This study aims to quantitatively interpret the emission characteristics in Eu2+-activated Na(Ba, Sr)PO4 solid solutions by tracking spectroscopic changes resulting from the modifications in the crystal structure when Ba2+ in NaBaPO4 is replaced by Sr2+. The broadband emission observed in Na(Ba, Sr)PO4: Eu2+ consists of three partially overlapping bands. Electron spin resonance (ESR) spectroscopy reveals that the three bands correspond to 4f65d1-4f7 interconfigurational electron transitions in crystallographically distinct three Eu2+. The distribution in three sites has not been observed in M3MgSi2O8 or A2MMgP2O8 (A: Li, Na, M: Ba, Ca, Sr), and specific to NaBaPO4 host. Because the emission wavelengths of the three Eu2+ ions are close, NaBaPO4: Eu2+ exhibits a high resultant emission intensity. Based on the Eu2+’s preference for sites with high Sr2+ occupancy, Eu2+ distribution and the associated Na(Ba, Sr)PO4: Eu2+ emission color can be tailored through Ba2+/Sr2+ replacement. The structure-emission relationship revealed in this study provides valuable insights for designing high-luminous-efficiency in glaserite-type phosphors.

The role of BaTiO3 nanoparticles as photocatalysts in the synthesis and characterization of novel fruit dyes is investigated.

In the present work, the photocatalytic activity against the natural dye extracted from the novel fruits has been studied by the BaTiO3 nanoparticles (NPs) under a ultra-violet (UV) light source. The large concentrations of an essential phenolic agent present in this phytochemical extract superimposed with cloths fibers make strong stain and degrade into another form of toxic, which is excluded from the many textiles industries as the colorful waste waters without recycling and removal of that dye pigments have been investigated using both photodegradation and photoluminescence techniques. The entitled nanoparticles (NPs) were prepared using the soft chemical root-modified solvothermal synthesis combo method and exposure to heat treatment such that the annealing process has been done for different temperatures ranging from 100°C to 250°C. As for as concern the characterization, as a start, structural and morphology studies have been reported here that highly crystalline oriented peaks data using powder x-ray diffraction techniques (PXRD) as well as the surface morphology including the size, shape, and mass distribution using the field emission scanning electron microscopy (FESEM) techniques, which purely belong to rutile tetragonal structure of the crystal system and circular and noncircular flakes like rough surface morphology materials respectively. The lattice dissociation constant 'ε' value of the BaTiO3 NPs has determined to be ~2.71 × 10-3 using the Williamson-Hall (W-H plot) analysis of crystallographic data. In the UV visible spectroscopy findings, since the extreme quantum confinement of BaTiO3 nanoflakes/nanodisc, the optical energy bandgap has been estimated to be a range of 1.98 to 2.67 eV (~2.48 eV) found from the Tauc plot analysis, which contributes to the significantly owing to the enhanced photocatalytic efficiency with excellent performance along exciton formation, superoxide ions, and hydroxyl free radicals generations under UV-vis light irradiation resulting in efficient degradation of typical novel fruit organic dye. Photoluminescence spectra observed at room temperature and low temperature have been observed for the BaTiO3 nanoflakes, which exhibit the blue emission due to the crystalline defects such as the appearance of Ba vacancies leads to the conceivable beginning of p-type conductivity and the origination of free exciton emission reveals the direct bandgap transition nature of nanoflakes. RESEARCH HIGHLIGHTS: According to our findings, 89.71% of the natural syzygium cumin is degraded by photocatalysis reaction. As a plausible mechanism for the destruction of natural dyes under solar light, photocatalytic destruction has been proposed. The reaction between these reactive free radical species leads to high efficiency photodegradation with a short decay time. In addition to water treatment and environmental cleaning applications, the excellent performance of this photocatalyst makes it a promising candidate for other applications. Hence, the synthesized BaTiO3 nanoflakes showcase a highly significant advancement towards the development of a textiles dye recycling method.

Phototuning of Multi-Color Emission in PMMA Composite Films for Information Encryption Applications

A strategy centered on dynamically tunable excited-state proton transfer (ESPT) processes is proposed for the design and synthesis of luminescent compounds. An emitter based on guanidine-substituted 1,8-naphthalimide (R-1) with ESPT characteristics has been meticulously engineered. Upon incorporation into poly (methyl methacrylate) (PMMA) matrices, the tunable ESPT process, transitioning between blue and yellow-green emission within the composite film, can be precisely controlled through irradiation in different pH environments. Moreover, the luminescence of the R-1/PMMA composite film exhibits variations in response to environmental changes, and demonstrates excellent fatigue resistance. Exploiting this characteristic, information such as “2020” can be encoded, and this encoded information automatically manifests in response to fluctuations in external pH. Specifically, employing a designated method is essential for accurately deciphering the information. The pH-dependent nature of this feature imparts a higher level of security to the material and offers new insights into information encryption.

Colloidal Synthesis of Blue-Emitting Cs3TmCl6 Nanocrystals via Localized Excitonic Recombination for Down-Conversion White Light-Emitting Diodes.

Lead-halide perovskite nanocrystals (NCs) have gained significant attention for their promising applications in lighting and display technologies. However, blue-emitting NCs have struggled to match the high efficiency of their red and green counterparts. Moreover, many reported blue-emitting perovskite NCs contain heavy metal lead (Pb), which poses risks to human health and the environment. In this study, we synthesized rare-earth-based Cs3TmCl6 NCs via the hot injection method, which exhibit a broadband blue emission at 440 nm. Combined experimental and theoretical studies indicate that the broadband emission in Cs3TmCl6 arises from self-trapped excitons due to the excited-state structural distortion of the [TmCl6]3- cluster. Furthermore, the ultrafast dynamics of charge carriers were analyzed using time-resolved photoluminescence and transient absorption measurements. Encouraged by the remarkable thermal, light, and water stabilities of Cs3TmCl6 NCs, as evidenced by experimental and theoretical results, a white light-emitting diode was further designed and fabricated using the Cs3TmCl6 NCs as the color converter. The device exhibits outstanding performance, achieving a long half-lifetime of 336 h and a large color-rendering index of 87.0. Combining eco-friendly features and a facile synthesis method, the rare-earth-based Cs3TmCl6 NCs mark a significant breakthrough as a reliable blue emitter, showcasing their future potential in lighting and display applications.

Novel Strategy of Treating 2-Nitrobenzoic Acid Crystals with Energetic N2 Neutrals Using Cold Plasma

The organic adduct compounds of 2-nitrobenzoic acid crystals were grown as optically transparent crystals using the conventional slow evaporation solution technique. The crystals were powdered and irradiated with cold plasma. Cell parameter analysis confirmed the formation of a new crystalline material that resides in the triclinic P crystal system with space group P1. Fourier transform infrared spectra were recorded using the KBr pellet technique to determine the vibrational functional groups in the compound. Powder X-ray diffraction analysis was used to reveal the crystalline orientation of the powdered samples of the grown crystals. The obtained full width at half maximum for the (001) plane in the XRD spectrum indicates the excellent crystalline quality of the 2-nitrobenzoic acid crystals. The recorded UV–Vis absorption spectra reveal that the grown powdered crystal samples possess cut-off edges wavelengths at 428 and 428 nm and 353 and 354 nm for pure and plasma-treated samples, respectively. The optical energy bandgaps were found to be 2.0, 2.25, 4.06, and 4.02 eV for the pure and plasma-treated samples, respectively. The photoluminescence spectra show the blue emissions of the crystal. The FE-SEM images show the morphological modifications in which rounded platelets appear on the surfaces of the treated crystals.

The Role of Spacers as a Probe in Variation of Photoluminescence Properties of Mono- and Bi-nuclear Boron Compounds.

A series of N,O donor-based mono- and binuclear four-coordinated boron complexes were synthesized. Depending on the substitution and spacer, these complexes exhibit intense blue, green and yellow emission in solution states. Notably, the fluorescence quantum yields (ФF) and fluorescence decay (lifetime, τ) of mononuclear boron complexes (2a-2e) were higher than the binuclear boron complexes (2f-2k). The lowest lifetime and quantum yield in binuclear boron complexes were due to intramolecular rotation induced non radiative processes. The disulphide spacer-based boron complexes2i-2kshowed aggregation-caused quenching in the THF/H2O mixture whereas no other complexes were ACQ responsive. These complexes show large Stokes shift, one of them i.e.2ehas the highest Stokes shift of 130 nm among them. Further, the electrochemical study suggests the presence of two redox incidences. Theoretical studies show close corroboration between the TD-DFT computed and experimentally measured absorption maxima as well as DFT (GIAO) calculated and experimentally measured11B NMR values. This complements the appropriate selection of the theoretical methods to shed light on the electronic transitions in the mono- and binuclear BF2complexes.

Repurposing expired metformin to fluorescent carbon quantum dots for ratiometric and color tonality visual detection of tetracycline with greenness evaluation

Repurposing expired drugs is highly significant as it prevents the accumulation of pharmaceutical wastes, optimizes resource usage, and reduces environmental harm. Metformin, used for type II diabetes, lowers blood sugar via decreasing liver glucose production and increasing muscle insulin sensitivity. However, the growing number of expired tablets annually necessitates a strategic approach for repurposing or reusing these tablets. Herein, we develop a simple hydrothermal approach for converting expired metformin to valuable fluorescent carbon quantum dots (m-CQDs) with sizes smaller than 10 nm. The m-CQDs displayed a blue emission at 420 nm when excited at 350 nm. Interestingly, when tetracycline (TC) was added, the blue emission diminished, and a greenish-yellow emission emerged at 530 nm. This emission tunning was the resulting of combination of inner filter effect and aggregation induced emission. Leveraging this dynamic emission tunning, we developed both ratiometric-based fluorescence and color tonality-based visual detection methods for detecting TC in pharmaceuticals and wastewater. More importantly, three assessment tools, ComplexMoGAPI, AGREE, and BAGI were used to evaluate the environmental sustainability of the proposed analytical method. The evaluation confirmed the sustainability of the method and the alignment with the greenness guidelines for analytical methods.

De(sulfon)amidative Cyclization: The Synthesis of Dibenzolactams and Dibenzosultams for Organic Light Emitting Diode Materials

This study addresses a challenge in organic synthetic chemistry: the direct cleavage of amide bonds, which is typically hampered by the thermodynamic stability of the C(Ar)–C(acyl) bond. Previous methods often rely on “CO” extrusion‐jointing transition metal‐catalyzed process and require activated tertiary amides, limiting their applicability due to incompatibility with reactive functional groups such as halogens. Herein, we report a transition metal‐free approach for the deamidative cyclization of biaryl diamides via a radical process, yielding dibenzolactam derivatives. Along this line, we have developed the desulfonamidative cyclization of biaryl disulfonamides to produce dibenzosultams through direct nucleophilic aromatic substitution, demonstrating high selectivity for unsymmetrical structures. Additionally, unsymmetrical sulfamoyl biaryl amides, containing both amide and sulfonamide functionalities, can selectively undergo desulfonamidative coupling with the amide to form dibenzolactams, which offers a complementary synthetic pathway to unsymmetric dibenzolactams. These protocols exhibit excellent compatibility with reactive functional groups, including halogens, providing an innovative synthetic toolbox for the development of thermally activated delayed fluorescence (TADF) materials used in organic light emitting diodes (OLEDs). DMAC‐PDO, incorporating a dibenzolactam as the acceptor unit, serves as an efficient blue TADF emitter with a maximum external quantum efficiency (EQEmax) of 23.4%.

De(sulfon)amidative Cyclization: The Synthesis of Dibenzolactams and Dibenzosultams for Organic Light Emitting Diode Materials.

This study addresses a challenge in organic synthetic chemistry: the direct cleavage of amide bonds, which is typically hampered by the thermodynamic stability of the C(Ar)-C(acyl) bond. Previous methods often rely on "CO" extrusion-jointing transition metal-catalyzed process and require activated tertiary amides, limiting their applicability due to incompatibility with reactive functional groups such as halogens. Herein, we report a transition metal-free approach for the deamidative cyclization of biaryl diamides via a radical process, yielding dibenzolactam derivatives. Along this line, we have developed the desulfonamidative cyclization of biaryl disulfonamides to produce dibenzosultams through direct nucleophilic aromatic substitution, demonstrating high selectivity for unsymmetrical structures. Additionally, unsymmetrical sulfamoyl biaryl amides, containing both amide and sulfonamide functionalities, can selectively undergo desulfonamidative coupling with the amide to form dibenzolactams, which offers a complementary synthetic pathway to unsymmetric dibenzolactams. These protocols exhibit excellent compatibility with reactive functional groups, including halogens, providing an innovative synthetic toolbox for the development of thermally activated delayed fluorescence (TADF) materials used in organic light emitting diodes (OLEDs). DMAC-PDO, incorporating a dibenzolactam as the acceptor unit, serves as an efficient blue TADF emitter with a maximum external quantum efficiency (EQEmax) of 23.4%.

Synthesis, Optical, Electrical, Fluorescence, Dielectric, Thermal, and Mechanical Characterization of 3-Aminopyridine (Scaffold in Drugs) Single Crystal

Objectives: To screen the optical, electrical, fluorescence, dielectric, thermal, and mechanical behavior of the 3-aminopyridine single crystal for its suitability in optoelectronic applications. Methods: A good single crystal of 3-aminopyridine (3-AP) was grown by the slow evaporation method. Findings: The lattice parameters of the grown crystal were determined using a single crystal X-ray diffractometer as, a = 6.184 (4) Å, b = 15.350 (6) Å, c = 5.361 (7) Å and the required functional groups C-N, NH2 bonds of 3-AP were recognized by the FTIR studies. The grown crystal was screened using the UV-Vis-NIR spectrum to understand the transmission and absorption character of the crystal. The various optical constants such as absorption coefficient, optical conductivity, and electrical conductivity of the crystal have been determined from the UV-Vis transmission plot. The lower cut-off wavelength of the 3-AP crystal was observed at 250 nm. The band gap of the grown crystal is found to be 4.5 eV. The emission property of the crystal was studied using fluorescence spectra. Violet, blue, and red emissions are observed from the fluorescence spectra. Thermal screening of the 3-AP crystal was performed using TGA and DTA. The 3-AP crystal remains stable up to 220 ºC and then the crystal begins to decompose up to 260 ºC due to the loss of the -NH2 group of the 3-aminopyridine. The Vickers hardness test revealed the nature of the material as soft type with Meyer’s index (n) of 2. The electronic polarization behavior of the crystal was examined using the dielectric study. Novelty: The lower cut-off wavelength of 250 nm, wide band gap of 4.5 eV, excellent transparency in the entire visible and near-infrared region, violet, blue, and red emission by the material are the distinguishing and mandatory features for optoelectronic applications. These features are good as compared to the 3-AP derivatives reported earlier. Keywords: Unit cell, Absorption, Emission, Conductivity, Strength, Loss

Mechanism of frequency-dependent gate breakdown in p-GaN/AlGaN/GaN HEMTs

In this Letter, time-dependent gate breakdown (TDB) characteristics under dynamic switching conditions were investigated in p-GaN/AlGaN/GaN high-electron-mobility transistors (HEMTs) with either Schottky-type or Ohmic-type gates. The dynamic TDB of the Schottky-type devices increased with frequencies ranging from 100 Hz to 100 kHz, while that of the Ohmic-type devices remained frequency-independent. This was analyzed by the frequency-dependent electroluminescence (EL) characteristics on both types of devices with semi-transparent gate electrodes. The electroluminescence (EL) emission intensity of Schottky-type devices increased with elevated frequencies, notably for blue and ultraviolet emissions, which exhibited a pronounced positive correlation with frequency. In contrast, the EL emissions of Ohmic-type devices were frequency-independent. Energy band diagrams were drawn to explain the different TDB and EL behaviors between two types of devices. The frequency-enhanced EL emissions of the Schottky-type devices indicated the frequency-enhanced hole injection and radiative recombination, which then suppressed the hot-electron effects on the metal/p-GaN junction and enhanced the dynamic TDB in p-GaN/AlGaN/GaN HEMTs.

Dual Sulfone-Bridged Triphenylamine Heteroaromatics for High-Performance Blue Organic Electroluminescence.

Polycyclic heteroaromatics (PHAs) are a highly versatile class of functional materials, especially applicable as efficient luminophores in organic light-emitting diodes (OLEDs). Those constructed by tethered phenyl surrounding the main group center attract extensive attention due to their excellent OLED device performance. However, the development of such a class of emitters is often limited to boron, nitrogen-doped π-conjugated heterocycles. Herein, we proposed a novel kind of blue emitter by constructing a donor-acceptor molecular configuration, utilizing a dual sulfone-bridged triphenylamine (BTPO) core and mono/di-diphenylamine (DPA) substituents. The twisted D-A molecular structures and appropriate donor strength facilitate the effective separation of natural transition orbitals, endowing the emitters with charge-transfer dominant hybridized local and charge-transfer characteristics for the excited states. Both BTPO-DPA and BTPO-2DPA own small S1-T1 splitting energy, thus demonstrating blue thermally activated delayed fluorescence. The more symmetrical structure and enhanced CT features brought by additional DPA moiety confer BTPO-2DPA with a shorter delayed fluorescence lifetime, a higher fluorescence quantum yield and narrower emission. Therefore, BTPO-2DPA based OLED devices exhibit superior blue electroluminescence performance, with external quantum efficiencies reaching 12.31 %.

High‐Efficiency Deep‐Blue Solution‐Processed Organic Light‐Emitting Diodes Using Carbazole Dendrons Modified Hybridized Local and Charge‐Transfer Emitters

In the pursuit of efficient and cost‐effective organic light‐emitting diodes (OLEDs), the development of solution‐processed hybridized local and charge transfer (HLCT) emitters presents a promising approach. HLCT materials uniquely integrate the advantages of both singlet and triplet excitons, surpassing the traditional spin statistical limit of 25% while offering high photoluminescence efficiency and balanced charge transport properties. Herein, we report the synthesis and characterization of two new deep blue, solution‐processable HLCT fluorophores, G1FTPI and G2FTPI. These compounds incorporate fluorenyl carbazole dendron units into the HLCT luminogenic triphenylamine‐phenanthroimidazole (TPI) molecule. Their HLCT and photoluminescence (PL) properties were experimentally and theoretically investigated using solvation effects and density functional theory (DFT) calculations. The molecules exhibit deep blue emission with a high solid‐state fluorescence quantum yield, good solution‐processed film‐forming quality, and high hole mobility values of 2.18 – 2.61 × 10‐6 cm2 V‐1s‐1. Both compounds were successfully employed as non‐doped emissive layers in solution‐processed OLEDs, demonstrating excellent electroluminescent (EL) performance. Notably, the G2FTPI‐based device emitted a deep blue light at 432 nm with CIE coordinates of (0.158, 0.098) and achieved a a maximum current efficiency (CEmax) of 3.13 cd A‐1 and a maximum external quantum efficiency (EQEmax) of 5.30%.

Conformational Modulation of Efficient Macrocyclic Emitters Featuring Delayed Fluorescence by Conjugation Length and Cavity Dimensions.

The π-conjugated macrocyclic emitters with thermally activated delayed fluorescence (TADF) characteristics have attracted widespread attention in the field of organic electroluminescence (EL) materials due to their unique geometries and excellent luminescence performance. Despite the significant impact of conjugation length and cavity dimensions on molecular conformation, the influence of these factors on the excited-state properties remains understudied. Herein, we formulated a strategy aimed at modulating the conformation of TADF macrocyclic molecules containing aniline as the donor (D) unit, and triazine as the acceptor (A), linked in D-A and D-π-A alternative macrocyclic construction (MC-TNT and MC-TST). Corroborated by experimental and theoretical analyses, the compact and conformationally twisted MC-TNT exhibits efficient blue luminescence in crystalline state, facilitating EL at high doping concentrations with maximum external quantum efficiency (EQEmax) of 13.9%, leading the field of blue macrocyclic emitters. Notably, MC-TST with π-bridge and flat conformation, demonstrates diminished Coulombic repulsion, achieving nearly 100% photoluminescence quantum yield and superior horizontal dipole orientation of 85% in 5 wt% doped films, and the corresponding device's EQEmax reaches record-high 32.7% within the TADF macrocyclic domain.

Conformational Modulation of Efficient Macrocyclic Emitters Featuring Delayed Fluorescence by Conjugation Length and Cavity Dimensions

The π‐conjugated macrocyclic emitters with thermally activated delayed fluorescence (TADF) characteristics have attracted widespread attention in the field of organic electroluminescence (EL) materials due to their unique geometries and excellent luminescence performance. Despite the significant impact of conjugation length and cavity dimensions on molecular conformation, the influence of these factors on the excited‐state properties remains understudied. Herein, we formulated a strategy aimed at modulating the conformation of TADF macrocyclic molecules containing aniline as the donor (D) unit, and triazine as the acceptor (A), linked in D‐A and D‐π‐A alternative macrocyclic construction (MC‐TNT and MC‐TST). Corroborated by experimental and theoretical analyses, the compact and conformationally twisted MC‐TNT exhibits efficient blue luminescence in crystalline state, facilitating EL at high doping concentrations with maximum external quantum efficiency (EQEmax) of 13.9%, leading the field of blue macrocyclic emitters. Notably, MC‐TST with π‐bridge and flat conformation, demonstrates diminished Coulombic repulsion, achieving nearly 100% photoluminescence quantum yield and superior horizontal dipole orientation of 85% in 5 wt% doped films, and the corresponding device's EQEmax reaches record‐high 32.7% within the TADF macrocyclic domain.

Intrinsic Narrowband Blue Phosphorescent Materials and Their Applications in 3D Printed Self-monitoring Microfluidic Chips.

Organic room-temperature phosphorescent (RTP) materials, especially with narrowband emission properties, exhibit great potential for applications in display and sensing, but have been seldom reported. Herein, a rare example of the intrinsic narrowband blue RTP material is fabricated and reported. A series of indolo[3,2,1-kl]phenothiazine derivatives, named Cphpz, 1O-Cphpz, and 2O-Cphpz, are designed and synthesized. Due to their relatively rigid structures, these three compounds showed deep blue narrowband emissions ranging from 396 to 434nm with the full width at half maximum (FWHM) of 31, 26, and 31nm, respectively. To the delight, compound 2O-Cphpz displayed intrinsic narrowband blue RTP at 448 nm with FWHM of 36 nm and a long-lived lifetime of 1.08 s in hydroxyethyl acrylate and acrylic acid matrix. Photophysical studies, single crystal analyses, and TD-DFT calculations are performed to elucidate further the relationships between molecular structures and the narrowband blue RTP properties. Meanwhile, because the narrowband blue RTP is highly sensitive to humidity, a visualizing droplet path optical microfluidic chip is efficiently fabricated through the digital light processing 3D printing.This work provides a rare example and a reliable strategy to realize narrowband blue RTP and further expand their applications in self-monitoring 3D printed structures.

Innovative synthesis and forensic applications of bio-mediated SrO–MgO–In[formula omitted]O[formula omitted] nanocomposites with blue photoluminescence

The first of its kind Strontium oxide–Magnesium Oxide–Indium oxide (SMI) nanocomposites were synthesized utilizing a bio-mediated method with Euphorbiatirucalli latex as a reducing agent, followed by calcination. Synthesis of SMI NCs is confirmed by Bragg reflections of SrO, MgO, and In2O3, among them peaks belonging to In2O3 are observed to be prominent. The crystallite size, and other parameters like dislocation density, strain, structural factor, and crystallinity were estimated. Due to lower surface energy and the adhesion of particles with weak forces, morphology of the surface contains a larger degree of agglomeration. The direct energy band gap was determined to be 3.18 eV. Furthermore, the PL (photoluminescence) emission spectra, CIE, and CCT coordinates strongly indicate high-intensity emission in the region of blue color. Dusting of powder reveals latent fingerprints. Synthesized SMI nanocomposite exhibits highly-resolved patterns in the form of ridges used to analyze specific latent fingerprints with clarity. Thus, the recently synthesized nanocomposite may have been used in forensics, fluorescence labeling, and blue light emission.

Green synthesis of highly fluorescent carbon quantum dots from almond resin for advanced theranostics in biomedical applications

Fluorescent Carbon Quantum Dots (CQDs) are being used in medical applications, particularly in theranostics. These Carbon Quantum Dots have been gaining more attention lately due to their potential as an effective replacement for hazardous synthetic organic dyes in a variety of biomedical applications, including live cell imaging and diagnostics. In this study, highly fluorescent Carbon Quantum Dots by one pot microwave based green route with a size of less than 10 nm, was prepared from commercially available almond resin, Prunus dulcis and conjugated with honey as additional reagent for surface functionalization. They exhibit a deep blue emission on excitation at 350 nm with an elevated quantum yield at 61%. They possess atomic nature and basic features such as high photo-stability, varying fluorescence, greater biocompatibility, and better water solubility. These fluorescent labels exhibit faster cellular invagination without disturbing the cell stability. The CQDs present cell imaging capacity with multi-coloration for visualizing the fine architecture of the nucleus naming, the nuclear membrane and nucleolus, which is linked with their varied, surface structures such as amphiphilic property and higher positive charges. These characteristics with minimal invasion have made carbon quantum dots to become the spotlight in theranostics. They can be used as alternatives to synthetic dyes for fluorescence- related cell-imaging. The intriguing fact about this approach is that it opens the possibility of combining therapy and diagnostics into one unit, which can alter how some diseases are handled and, in turn, transform the field of healthcare.

Supramolecular Luminescent Copper-Nanocluster-Based Dough with Excellent Electrical Conductivity Sensing Properties.

In recent years, the rapid advancement of flexible conductive materials has significantly increased the demand for dough materials that offer high flexibility and conductivity for diverse applications. Here, we developed a flexible, stretchable, and self-healing dough utilizing hydrogen-bonding interactions between glutathione-stabilized copper nanoclusters (GSH-Cu NCs) and poly(acrylic acid) (PAA). The dough materials can be kneaded, readily reshaped, and further processed to create bulk materials of arbitrary form factors. The incorporation of PAA not only preserved the vibrant blue emission of GSH-Cu NCs but also enhanced their electrical conductivity and stretchability. The dough can be stretched up to 25 times its initial length and achieves complete self-healing in a short time. Moreover, the dough can automatically repair physical damage and return to its initial conductivity levels after healing. Surprisingly, the electrical conductivity of the dough can reach as high as 2.97 S/m, which is relatively superior compared to that of conventional conductive materials. This study presents a dough that serves as a highly sensitive strain sensor, capable of effectively monitoring human movement across a broad range of strains.

Intense and Stable Blue Light Emission From CsPbBr3/Cs4PbBr6 Heterostructures Embedded in Transparent Nanoporous Films

AbstractLead halide perovskite nanocrystals are attractive for light emitting devices both as electroluminescent and color‐converting materials since they combine intense and narrow emissions with good charge injection and transport properties. However, while most perovskite nanocrystals shine at green and red wavelengths, the observation of intense and stable blue emission still remains a challenging target. In this work, a method is reported to attain intense and enduring blue emission (470–480 nm), with a photoluminescence quantum yield (PLQY) of 40%, originating from very small CsPbBr3 nanocrystals (diameter < 3 nm) formed by controllably exposing Cs4PbBr6 to humidity. This process is mediated by the void network of a mesoporous transparent scaffold in which the zero‐dimensional Cs4PbBr6 lattice is embedded, which allows the fine control over water adsorption and condensation that determines the optimization of the synthetic procedure and, eventually, the nanocrystal size. The approach provides a means to attain highly efficient transparent and stable blue light‐emitting films that complete the palette offered by perovskite nanocrystals for lighting and display applications.