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Photonic glasses (PGs) based on the self-assembly of monosized nanoparticles can be an effective tool for realizing disordered structures capable of tailoring light diffusion due to the establishment of Mie resonances. In particular, the wavelength position of these resonances depends mainly on the morphology (dimension) and optical properties (refractive index) of the building blocks. In this study, we report the fabrication and optical characterization of photonic glasses obtained via a self-assembling technique. Furthermore, we have demonstrated that the infiltration of these systems with a green-emitting polymer enhances the properties of the polymer, resulting in a large increase in its photoluminescence quantum yield and a 3 ps growing time of the photoluminescence time decay Finally, the development of the aforementioned system can serve as a suitable low-cost platform for the realization of lasers and fluorescence-based bio-sensors.

Quinoa has been identified as a climate-resilient crop that can overcome unfavorable conditions. This study explores the photochemical efficiency of quinoa compared to maize subjected to drought stress. The JIP-test was used to assess the photochemical efficiency of both crops. Proline content, leaf water potential, and membrane leakage were also determined. The maximum photochemical efficiency (Fv/Fm) did not change for quinoa and maize under moderate stress. However, severe drought conditions resulted in a decline in Fv/Fm in maize but not quinoa. Furthermore, the PSII performance index (PIABS,total) declined steadily in maize soon after the onset of drought stress. The decline in the PIABS,total values for quinoa was only observed after a period of severe drought stress. Membrane leakage was also more prevalent in the maize plants, while quinoa had higher proline contents. This study concluded that both quinoa and maize maintained PSII structure and function under moderate drought conditions. However, only quinoa maintained PSII structure and function under severe drought conditions.

An introduction to articles published in the issue which focused on advances in photokinetics is presented on topics including sunlight-based photocatalysis for the purpose of simultaneously degrading a wide variety of pollutants from polluted water sources, an illustration of a biological photosystem, and fundamental photo kinetic concepts and tools.

Aiming at the low luminous‐efficiency of two‐dimensional (2D) perovskite, its quantum yield (QY) and stability are effectively improved by a fluorinated second insulator layer 3,4‐difluoroaniline (F2PA) outside of the first insulator 2‐(2,4‐difluorophenyl) ethylamine (FPEA). The QY of perovskite with two insulator layers is improved by 3.4‐time in contrast with its counterpart with one insulator, which originates from the defect suppression and reduction of exciton Bohr radius by the second layer. The optical stability has extended 1.5‐time by the introduced second layer, as an isolation role for inner decomposed products to volatilize and for outer water molecules to penetrate. The perovskite with two insulator layers retained 90% of its initial optical properties in relative humidity 90%–95% atmosphere for 600 h, meanwhile only 50% for its counterpart with one layer. Two‐more fluorine with stronger hydrophobicity can account for this feature. Adding a second insulator layer is an effective strategy to engineer 2D perovskites and push forward its applications in optoelectronic devices. [ABSTRACT FROM AUTHOR]

A hydrogen‐bonded solvate (HBS) model is herein proposed to construct hydrogen‐bonded organic frameworks (HOFs), for enhancing the solid‐state one‐/two‐photon excited fluorescence (1/2PEF) of organic fluorophores. Two photonic HOFs (ZJU‐HOF‐25 and ZJU‐HOF‐26) are synthesized by using the same organic fluorophore and the fluorophore in them features similar arrangement. The most obvious structural distinction between the two HOFs is the existence of solvent molecules in the crystal cell of ZJU‐HOF‐25. ZJU‐HOF‐25 is regarded as an ideal HBS material where solvent molecules separate fluorophores apart just like dissolving them. But ZJU‐HOF‐26 contains no solvent molecules and the fluorophores are connected directly via hydrogen bonds among them. A significant quantum yield (η) increase is realized from amorphous fluorophores (η ≈0%) to HBS‐based ZJU‐HOF‐25 (η ≈21.75%), while ZJU‐HOF‐26 displays poor 1PEF (η ≈0%). ZJU‐HOF‐25 also exhibits much stronger 2PEF with the two‐photon action cross section larger than ZJU‐HOF‐26 by almost two orders of magnitude. These phenomena are mainly attributed to that the solvent molecules in ZJU‐HOF‐25 benefit the homogeneous separation and conformation fixation of fluorophores, suppressing the non‐radiative transition. The HBS model thus shows the fantastic validity to improve solid‐state optical properties of organic materials, providing guidance for exploring advanced optical materials. [ABSTRACT FROM AUTHOR]

Recently, near-infrared (NIR) light-emitting diodes (LED) have attracted much research attention globally. To advance this technology, NIR phosphors with high efficiency, thermal stability, and broad bands are required. In this work, we modified ZnGa 2 O4:Cr3+ phosphor with Mg2+ ions. Results show that this method improves the luminescence intensity of ZnGa 2 O4:Cr3+ phosphor, and the emission wavelength of the sample can be changed by doping different Mg2+ concentrations. This method also improved the thermal stability of the samples. The quantum yield of Mg-modified ZnGa 2 O 4 :Cr3+ phosphors reached 87.12%, and the white LED fabricated with Zn 0.4 Mg 0.6 Ga 2 O 4 :0.01Cr3+ phosphor and commercial Y 3 Al 5 O 12 :Ce3+ phosphor demonstrated good performance. The NIR-LED fabricated with Zn 0.4 Mg 0.6 Ga 2 O 4 :0.01Cr3+ phosphor achieved a photoelectric conversion efficiency of 7.17%. The lines on the surface of an orange taken by a NIR camera reveal that phosphor can be used in night vision lighting. Meanwhile, the distribution of blood vessels in the human palm highlights the promising biological applications of the Zn 0.4 Mg 0.6 Ga 2 O 4 :0.01Cr3+ phosphor. [ABSTRACT FROM AUTHOR]

Lead-free perovskite is one of the ideal solutions for the toxicity and instability of lead halide perovskite quantum dots. As the most ideal lead-free perovskite at present, bismuth-based perovskite quantum dots still have the problem of a low photoluminescence quantum yield, and its biocompatibility also needs to be explored. In this paper, Ce3+ ions were successfully introduced into the Cs3Bi2Cl9 lattice using a modified antisolvent method. The photoluminescence quantum yield of Cs3Bi2Cl9:Ce is up to 22.12%, which is 71% higher than that of undoped Cs3Bi2Cl9. The two quantum dots show high water-soluble stability and good biocompatibility. Under the excitation of a 750 nm femtosecond laser, high-intensity up-conversion fluorescence images of human liver hepatocellular carcinoma cells cultured with the quantum dots were obtained, and the fluorescence of the two quantum dots was observed in the image of the nucleus. The fluorescence intensity of cells cultured with Cs3Bi2Cl9:Ce was 3.20 times of that of the control group and 4.54 times of the control group for the fluorescence intensity of the nucleus, respectively. This paper provides a new strategy to develop the biocompatibility and water stability of perovskite and expands the application of perovskite in the field. [ABSTRACT FROM AUTHOR]

In this study, we fabricated three different ZnO tetrapodal nanostructures (ZnO-Ts) by a combustion process and studied their physicochemical properties by different techniques to evaluate their potentiality for label-free biosensing purposes. Then, we explored the chemical reactivity of ZnO-Ts by quantifying the available functional hydroxyl groups (–OH) on the transducer surface necessary for biosensor development. The best ZnO-T sample was chemically modified and bioconjugated with biotin as a model bioprobe by a multi-step procedure based on silanization and carbodiimide chemistry. The results demonstrated that the ZnO-Ts could be easily and efficiently biomodified, and sensing experiments based on the streptavidin target detection confirmed these structures' suitability for biosensing applications. [ABSTRACT FROM AUTHOR]

Chemical actinometry can be used to determine photons absorbed for a photochemical reaction, which is required to calculate the quantum yield. A photochemical reaction with a known quantum yield can be used as a relative standard for the determination of an unknown quantum yield for a light-driven reaction. Herein, we have developed a simplified approach to using the popular potassium ferrioxalate actinometer. Traditionally, the photoreduction of Fe(III) to Fe(II) is monitored by following the absorbance of Fe(II) by reacting aliquots of the actinometry solution with 9,10-phenanthroline to form a red colored complex. The multiple steps for this method make it tedious and vulnerable to errors, especially inadvertent light exposure. In lieu of spectroscopic measurements of the Fe(II) concentration, the production of CO2 was measured to determine the number of photons absorbed over time. CO2 production was measured in two different ways: by the pressure increase in a sealed system and the volume change by trapping the CO2. Both methods were considerably less laborious and showed agreeable results compared with the traditional spectroscopic method. [ABSTRACT FROM AUTHOR]

In order to find new functional materials and materials with improved performance for next-generation electrochemical devices, several new materials for various purposes have been synthesized. In particular, BiVO4 films were obtained by electrochemical synthesis using interferometric control of film thickness during their deposition. Previously, it was found that the use of thin BiVO4 films with a thickness of 150 to 400 nm is most effective, where an increase in the quantum yield of photocurrent up to 0.25 at λ of 400 to 450 nm was observed. LiFePO4 was synthesized in DES medium (low-temperature eutectic solvents): choline chloride-triethylene glycol (ChCl-TEG) and choline chloride-ethylene glycol (ChCl-EG) using NH4FePO4 and CH3COOLi as precursors. It was found that the mode of synthesis of LiFePO4/C at 973 К for 1 h does not lead to oxidation of LiFePO4, as evidenced by the values of the ratio Fe2+/Fe3+ for LiFePO4 and LiFePO4/C, which are 2.4 and 2.7, respectively. It was found that the substitution of a part of lead cations (up to 20 mol. %), in the composition of the fluoride-conducting phase Pb0.86Sn1.14F4, contributes to the increase of its conductivity in the whole temperature range, the higher the concentration of the substituent, to a greater extent. Charge transfer is provided by highly mobile interstitial fluorine anions, the concentration of which increases with the rise of temperature and substituent content. [ABSTRACT FROM AUTHOR]

By using anhydrous conditions, we report here an optimized synthesis of small but highly emitting upconverting nanoparticles (UCNPs) of LiYF4:Yb3+, Tm3+ without any surface passivation layers of silica or undoped matrix. For this, anhydrous precursors [Li-(TFA)-(monoglyme)] and [Ln-(TFA)3(monoglyme)] (Ln = Y, Gd, Tm, Yb; TFA = trifluoroacetate) were synthesized via a facile one-pot synthetic protocol, which showed excellent thermal decomposition compatibility to afford Ln3+-doped LiLnF4 NPs by simultaneous decomposition in the solution phase. A detailed study of the influence of many key parameters such as the ratio of dopant ions and solvents, concentration of precursors, reaction time, and temperature over crystalline phase, size, shape, morphology, and upconverting properties of the NPs produced followed by a mechanism for the formation of LiYF4-based NPs is presented. The high quality of these NPs is manifested by the fact that their upconversion efficiency is quite comparable to that of a bulk single crystal of the same composition (bulk materials are believed to have far better UC performance due to low surface area and less defects). Successful incorporation of these UCNPs in transparent TiO2 metallogels provided an alternative strategy of highly homogeneous UCNP-TiO2 composites of variable composition (1–10% of NPs) having very high specific surface area (435–580 m2/g). [ABSTRACT FROM AUTHOR]

Lead–halide perovskite nanocrystals are an attractive class of materials since they can be easily fabricated, their optical properties can be tuned all over the visible spectral range, and they possess high emission quantum yields and narrow photoluminescence linewidths. Doping perovskites with lanthanides is one of the ways to widen the spectral range of their emission, making them attractive for further applications. Herein, we summarize the recent progress in the synthesis of ytterbium-doped perovskite nanocrystals in terms of the varying synthesis parameters such as temperature, ligand molar ratio, ytterbium precursor type, and dopant content. We further consider the dependence of morphology (size and ytterbium content) and optical parameters (photoluminescence quantum yield in visible and near-infrared spectral ranges) on the synthesis parameters. The developed open-source code approximates those dependencies as multiple-parameter linear regression and allows us to estimate the value of the photoluminescence quantum yield from the parameters of the perovskite synthesis. Further use and promotion of an open-source database will expand the possibilities of the developed code to predict the synthesis protocols for doped perovskite nanocrystals. [ABSTRACT FROM AUTHOR]

Mn(II)-based perovskite materials are being intensively explored for lighting applications; understanding the role of ligands regarding their photobehavior is fundamental for their development. Herein, we report on two Mn (II) bromide perovskites using monovalent (perovskite 1, P1) and bivalent (perovskite 2, P2) alkyl interlayer spacers. The perovskites were characterized with powder X-ray diffraction (PXRD), electron spin paramagnetic resonance (EPR), steady-state, and time-resolved emission spectroscopy. The EPR experiments suggest octahedral coordination in P1 and tetrahedral coordination for P2, while the PXRD results demonstrate the presence of a hydrated phase in P2 when exposed to ambient conditions. P1 exhibits an orange-red emission, while P2 shows a green photoluminescence, as a result of the different types of coordination of Mn(II) ions. Furthermore, the P2 photoluminescence quantum yield (26%) is significantly higher than that of P1 (3.6 %), which we explain in terms of different electron-phonon couplings and Mn-Mn interactions. The encapsulation of both perovskites into a PMMA film largely increases their stability against moisture, being more than 1000 h for P2. Upon increasing the temperature, the emission intensity of both perovskites decreases without a significant shift in the emission spectrum, which is explained in terms of an increase in the electron-phonon interactions. The photoluminescence decays fit two components in the microsecond regime—the shortest lifetime for hydrated phases and the longest one for non-hydrated phases. Our findings provide insights into the effects of linear mono- and bivalent organic interlayer spacer cations on the photophysics of these kinds of Mn (II)-based perovskites. The results will help in better designs of Mn(II)-perovskites, to increase their lighting performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • A bioinspired molecule with a dipeptide-like structure and active silanol groups was designed successfully. • The QY of h-PDs in aqueous solution and solid state reached as high as 98.2% and 96.3%, respectively. • The emission behavior of non-aromatic fluorescent materials under sunlight was achieved for the first time. • This work provides a design strategy for synthesizing high-fluorescence QY non-aromatic fluorescent materials. In recent years, non-aromatic fluorescent materials have attracted widespread attention, but achieving a high quantum yield ( QY ) in their dilute solutions still remains a challenge. In this work, inspired by the Clustering-triggered emission (CTE) phenomenon of non-aromatic amino acids and poly(amino acids), we successfully designed a bioinspired molecule with a dipeptide-like structure and active silanol groups. The as-prepared bioinspired molecule can be hydrolyzed by simple heating to obtain the hydrolysate h-PDs , which can emit strong blue fluorescence in dilute solution. And this was the first time to realize the emission behavior of non-aromatic fluorescent materials under sunlight. The QY of h-PDs in aqueous solution and solid state were as high as 98.2% and 96.3%, respectively, which were attributed to the condensation of active silanol groups at the end of the molecule, and the existence of hydrogen bonds and N → Si coordination bonds that made small molecules cross-linked and aggregated into dense clusters. Finally, the application of h-PDs in the detection of intracellular and exogenous Hg2+ and Cys and luminescent films were also explored. Significantly, this work provides a design strategy for synthesizing high-fluorescence QY non-aromatic fluorescent materials, and verifies their potential application value in the fields of environment, biology and light-emitting devices. [ABSTRACT FROM AUTHOR]

In this work, we used chitosan as a raw material to synthesize carbon dots using fast microwave carbonization. We studied the influence of the synthesis time, doping agent, and the molar ratio between the reactants on the quantum yield of carbon dots. Chitosan-based carbon dots displayed stable blue fluorescence emission with excitation-dependent behavior and quantum yield values ranging from 1.16 to 7.07 %. ANOVA results showed that the interaction factor between the doping agent and the molar ratio of the reactants was a significant combination to produce carbon dots with higher quantum yield. The presence of the doping agent improved the carbon dots optical properties by obtaining higher fluorescence intensity values. Confocal laser microscope images showed that the carbon dots internalized in the Candida albicans cellular membrane, exhibiting blue, green, and red emissions, acting as a promising agent for bioimaging. • Chitosan-based carbon dots are synthesized by a fast and simple microwave approach. • Synthesis conditions modulation is essential to improve the fluorescent properties. • Statically, the synergy of molar ratio and doping agent leads higher quantum yields. • Chitosan-based carbon dots bind specifically with ergosterol from Candida albicans. • Chitosan-based carbon dots functioned as a bioimaging agent for Candida albicans. [ABSTRACT FROM AUTHOR]

Quantum dots (QDs) have attracted great attention as tools for theranostics that combine the possibility of simultaneous biological target visualization and medicine delivery. Here, we address whether core/shell InP/ZnS QDs (InP-QDs) may be an alternative to toxic Cd-based QDs. We analyze InP-QD photophysical characteristics in cell culture medium, salt solutions, and directly in the cells. It was demonstrated that InP-QDs were internalized into endolysosomes in HeLa and A549 cells with dynamics similar to Cd-based QDs of the same design, but the two cell lines accumulated them with different efficiencies. InP-QDs were reliably detected in the endosomes despite their low quantum yields. Cell culture medium efficiently decreased the InP-QD photoluminescence lifetime by 50%, acidic pH (4.0) had a moderate effect (20–25% reduction), and quenching by salt solutions typical of intra-endosomal medium composition resulted in a decrease of about 10–15%. The single-vesicle fluorescence-lifetime imaging microscopy analysis of QDs inside and outside the cells shows that the scatter between endosomes in the same cell can be significant, which indicates the complex impact of the abovementioned factors on the state of InP-QDs. The PI test and MTT test demonstrate that InP-QDs are toxic for both cell lines at concentrations higher than 20 nM. Possible reasons for InP-QD toxicity are discussed. [ABSTRACT FROM AUTHOR]

Six samarium (III) complexes were synthesised by employing the β-ketocarboxylic acid as main ligand and five N-donor systems as ancillary ligands through the environmentally safe liquid-assisted grinding method. Various characterisation techniques were employed to determine the structure of the complexes i.e. NMR, IR, XRD and SEM. Photoluminescent studies were carried out in solid as well as in solution form. In solid and solution form emission spectra show maximum intensity peak at 604 and 602 nm, respectively, assigned to 4G5/2 → 6H7/2 transition which explains orange emission on UV excitation in complexes. CCT, CP, colorimetric parameters and quantum yield (relative and intrinsic) of the synthesized complexes were calculated. With the help of reflectance spectra, band gap and Urbach energy were determined. Lasing parameters were also calculated by employing FWHM values obtained from Gaussian fitting. Energy transfer study revealed the efficacious energy transfer from ligand to metal's emissive level. Further antimicrobial studies revealed higher activity in case of complexes in comparison to ligand. [ABSTRACT FROM AUTHOR]

To achieve the quantum yield and color purity suitable for applications to the visible emitters in display devices, the optical features of indium phosphide (InP) quantum dots (QDs) are improved. Two types of InP cores are synthesized with two kinds of the phosphorus precursors, tris-(trimethylsilyl)-phosphine and tris-(dimethylamino)-phosphine. The prepared cores are fabricated for the gradient-alloyed inner shell (ZnSeS) and outer shell (ZnS) to complete the environmentally benign QDs with the structures of core/inner-shell/outer-shell. The quantum yields in the two types of QDs are 95 and 85% with the bandwidths of 35 and 36 nm, respectively, comparable to the characteristics of state-of-the-art InP QDs. The band-to-band transition of the neutral states in QDs turns out to be more efficient than the band-to-hole transition, whereas the optical transitions of the charged states are not strong. Despite the similar peak shapes with the equivalent Stokes shift, the optical features investigated by temperature-dependent and time-resolved spectroscopy are distinctive in the two types of QDs. In particular, the formation of the charged states and localized states, in addition to the dark states, is influenced by the precursors. These findings suggest strategies to enhance the quantum yield and color purity of InP QDs for applications to display devices with a green chemistry approach. [ABSTRACT FROM AUTHOR]

Novel benzo[1,2‐b:4,3‐b′]dinaphthofuran (oxa[7]helicene) with various substituents in the central ring were designed and successfully synthesized based on the late stage central ring formation strategy from naphthofuranoneby using an efficient McMurry coupling or Friedel‐Crafts acylation. The photochemical properties of helicenes were evaluated by UV‐Visible absorption spectroscopy and fluorescence spectroscopy, while electrochemical behaviour including their energy profile were investigated by cyclic voltammetry and DFT calculations. According to the computational study, substituents on the central ring could influence both electron delocalization and MO distribution of oxa[7]helicenes resulting in the change in charge transporting ability. In comparison to the parent carbo[7]helicene, the furan unit in conjunction with substituents on helical system caused the bathochromic shift with different absorption pattern and exhibited higher fluorescence quantum yield (ϕf up to 0.63). These new materials showed promising characteristics in optoelectronic application. [ABSTRACT FROM AUTHOR]

Tailored modifications of halide lead‐free perovskites (LFPs) via doping/alloying with metal cations have been recognized as a promising pathway to highly efficient inorganic phosphors with photoluminescence (PL) quantum yields of up to 100 %. Such materials typically display selective sensitivity to UV light, a broad PL range, and long PL lifetimes as well as a unique compositional variability and stability—an ideal combination for many light‐harvesting applications. This Minireview presents the state‐of‐the‐art in doped LFPs, focusing on the reports published mostly in the last two to three years. We discuss the factors determining the efficiency and spectral parameters of the broadband PL of doped LFPs depending on the dopant and host matrix, both in micro‐ and nanocrystalline states, address the most relevant challenges this rapidly developing research area is facing, and outline the most promising concepts for further progress in this field. [ABSTRACT FROM AUTHOR]

Three general effective strategies are shown to mitigate nonradiative losses in the superradiant emission from supramolecular assemblies. J‐aggregates of 5,5′,6,6′‐tetrachloro‐1,1′‐diethyl‐3,3′‐di(4–sulfobutyl)‐benzimidazolocarbocyanine (TDBC) are used to elucidate the nature of nonradiative processes. Self‐annealing at room temperature (RT), photo‐brightening, and purification of the dye monomers are shown to all lead to substantial increases in emission quantum yields (QYs) and a concomitant lengthening of the emission lifetime, with purification having the largest effect. Structural and optical measurements are used to support a microscopic model that emphasizes the deleterious effects of a small number of impurity and defect sites that serve as nonradiative recombination centers. This understanding has yielded a molecular fluorophore in solution at RT with an unprecedented combination of fast emissive lifetime and high QY. Superradiant emission with a QY of 82% and a lifetime of 174 ps is obtained from J‐aggregates of TDBC in solution at RT. This combination of high QY and fast lifetime at RT makes supramolecular assemblies of purified TDBC a model system for the study of fundamental superradiance phenomena. High QY J‐aggregates are uniquely suited for the development of applications that require high speed and high brightness fluorophores such as devices for high‐speed optical communication. [ABSTRACT FROM AUTHOR]

Multiple exciton generation solar cells exhibit low power conversion efficiency owing to non-radiative recombination, even after the generation of numerous electron and hole pairs per incident photon. This paper elucidates the non-idealities of multiple exciton generation solar cells. Accordingly, we present mathematical approaches for determining the quantum yield to discuss the non-idealities of multiple exciton generation solar cells by adjusting the delta function. We present the use of the Gaussian distribution function to present the occupancy status of carriers at each energy state using the Dirac delta function. Further, we obtained ideal and non-ideal quantum yields by modifying the Gaussian distribution function for each energy state. On the basis of this approach, we discuss the material imperfections of multiple exciton generations by analyzing the mathematically obtained quantum yields. Then, we discuss the status of radiative recombination calculated from the ratio of radiative to non-radiative recombination. Finally, we present the application of this approach to the detailed balance limit of the multiple exciton generation solar cell to evaluate the practical limit of multiple exciton generation solar cells. [ABSTRACT FROM AUTHOR]

Temperature is an important physical parameter and plays a significant role in scientific research, the detection of which cannot be too crucial to study. In order to reduce the interference of the external environment on the detection of temperature and improve the accuracy of the detection results, a multi-parameter detection method using several optical signals was proposed. Here, a novel porous metal–organic framework (MOF), Zn-CYMPN, was synthesized and structurally characterized. Then, fluorescent organic dyes, either DPEE or DPEM, were encapsulated into the pores of Zn-CYMPN independently. The successful synthesis of the composites Zn-CYMPN⊃DPEE or Zn-CYMPN⊃DPEM could easily introduce other fluorescent centers into the original material and made it more convenient to realize multi-parameter temperature detection. More specifically, when the temperature changed, the maximum fluorescent emission wavelength (W) and the maximum optical intensity (I) of the Zn-CYMPN⊃DPEE/DPEM both showed good linear responses with temperature over a wide range, indicating that the composites were highly sensitive thermometers with multi-parameter temperature readouts. In addition, the quantum efficiency and thermal stability of the organic dyes, which bother every researcher, were improved as well. [ABSTRACT FROM AUTHOR]

The cyan emission band contains blue and green light regions, which can simplify the fabrication process of white light-emitting diodes and help promote the development of solid-state lighting. In this paper, a series of Eu2+ singly doped and Eu2+ and Li+ co-doped cyan light-emitting KAlSiO 4 : x Eu2+, y Li + materials were synthesized using the high temperature solid-state method. It was found that the incorporation of 10% Li + could increase the emission intensity of the KAlSiO 4 :0.02Eu2+ sample by up to a factor of ∼3. This also shifted the emission color of the sample from blue-cyan (472 nm) to cyan (485 nm), and the quantum yield was increased from 71.5% to 93.3%. When the temperature is increased to 150 °C, the peak emission intensity was increased from 75.9% to 92.7% of that at room temperature. DFT calculations were used to demonstrate that the KAlSiO 4 phosphor host possesses a wide bandgap of 4.86 eV and the experimentally-determined optical bandgap of the phosphor was 5.6 eV. The phosphor was combined with a commercial red phosphor, and these together were used as the emitting components in a white LED package. The characteristics of the white LED when using two representative samples of the phosphor (KAlSiO 4 : 0.02Eu2+ and KAlSiO 4 : 0.02Eu2+, 0.1Li+) were examined; these white LEDs had color rendering indices of 82 and 95, and color temperatures of 5656 K and 4126 K respectively. This work demonstrates the significant potential that KAlSiO 4 :0.02 Eu2+, 0.1 Li+ phosphors have in the field of LED lighting. [ABSTRACT FROM AUTHOR]

Flame synthesis could represent a controllable method for production of carbon dots (CDs) with tunable emission properties, alternative to process involving oxidation agents and wet chemistry processing. To control final properties of CDs, a thorough analysis of different reactor parameters has to be conducted. Here we investigate the effect of combustion operative conditions, namely equivalence ratio, for CD production in a premixed flame reactor. CDs with specific optical properties have been synthesized at different equivalence ratios, burning both pure ethylene and ethylene/benzene mixtures. Carbon particulate matter was thermophoretically collected at the exhaust of the flame reactor. Successively, after dichloromethane washing, CDs were simply obtained by N-methyl-pyrrolidone extraction and filtration (<20 nm). In ethylene flames, CDs with fluorescence ranging from green to yellow, as equivalence ratio increases, were synthesized. In ethylene/benzene flames, produced CDs emit fluorescence from blue to green and equivalence ratio seems to play even a more marked role, inducing significant change in the emission spectra with small changes of equivalence ratio. Globally, their quantum yield ranges between 2 and 11%. CDs have been found generally stable for mild change of temperature (up to 80 °C), mild basic pH (pH = 8–10) and over long time at room temperature (up to 240 days). Overall, equivalence ratio demonstrates to be a powerful and simple tool to produce tunable CDs by flame synthesis on large scale. [Display omitted] • Equivalence ratio is used as reactor parameter to produce carbon dots in aliphatic and aromatic fuel combustion. • Carbon dots can be easily extracted from total particulate with organic solvent. • Blue-to-yellow fluorescing with different quantum yield carbon dots are produced by tuning equivalence ratio. • TEM showed the amorphous character and the nanometric size of carbon dots. • Carbon dots produced show a good stability over time, mild temperature (up to 80 °C) and mild basic pH (8–10). [ABSTRACT FROM AUTHOR]

Over the past two decades, it has become abundantly clear that nucleic acid biochemistry, especially with respect to RNA, is more convoluted and complex than previously appreciated. Indeed, the application and exploitation of nucleic acids beyond their predestined role as the medium for storage and transmission of genetic information to the treatment and study of diseases has been achieved. In other areas of endeavor, utilization of nucleic acids as a probe molecule requires that they possess a reporter group. The reporter group of choice is often a luminophore because fluorescence spectroscopy has emerged as an indispensable tool to probe the structural and functional properties of modified nucleic acids. The scope of this review spans research done in the Hudson lab at The University of Western Ontario and is focused on modified pyrimidine nucleobases and their applications as environmentally sensitive fluorophores, base discriminating fluorophores, and in service of antisense applications as well as tantalizing new results as G‐quadruplex destabilizing agents. While this review is a focused personal account, particularly influential work of colleagues in the chemistry community will be highlighted. The intention is not to make a comprehensive review, citations to the existing excellent reviews are given, any omission of the wonderful and impactful work being done by others globally is not intentional. Thus, this review will briefly introduce the context of our work, summarize what has been accomplished and finish with the prospects of future developments. [ABSTRACT FROM AUTHOR]

Lead-free perovskites are a new type of luminescent material with non-toxic, stability and excellent photoelectric properties, which have great application in the field of photoelectric detection, solar cells, bio-imaging, etc. Here, we reported a new kind of uniform spherical rare-earth based double perovskite Cs 2 NaYCl 6 nanocrystals (NCs) as versatile hosts to accommodate ionic dopants for improving photoelectric properties especially the luminescent properties. In contrast to the low quantum yield of only 5.62%, the luminescent intensity of Cs 2 NaYCl 6 NCs can be impressively enhanced via doping Sb3+ and Mn2+ ions in the rare earth-based double perovskite lattices. For the Sb3+-doping, the photoluminescence quantum yield (PLQY) increases from 5.62% to 22.48%. On this basis, the luminescence colors can be tuned from blue to white and red via Mn2+ ions doping and the maximum PLQY can be further improved to 38.66%. Finally, the Sb3+, Sb3+/Mn2+ ions doped Cs 2 NaYCl 6 NCs based blue, red and white LEDs were explored, which indicates that these are potential materials in multicolor LEDs applications. [ABSTRACT FROM AUTHOR]

The detection of tetracycline antibiotics in environmental waters is crucial due to their widespread use, persistence, and potential toxicity. Herein, a method for the specific detection of tetracycline in aquaculture wastewater using a nitrogen-doped carbon quantum dots fluorescence probe is reported. Nitrogen-doped carbon quantum dots (N-CQDs) were synthesized in one step via a hydrothermal method, employing citric acid as the carbon source and diethylenetriamine as the nitrogen source. The resulting N-CQDs exhibit excellent stability, solubility and fluorescence properties. Upon the introduction of tetracycline, a fluorescence burst can be observed, indicating that the N-CQDs function as a ratio fluorescence probe. The fluorescence burst phenomenon is primarily due to the internal filtering effect. In the case of N-CQDs, this burst is attributed to the overlap between the absorption spectrum of tetracycline and the emission spectrum of the carbon quantum dots, which results in internal filtering. The linear range for tetracycline detection spans from 54.2 nM to 0.8 μM, with a detection limit of 54.2 nM. The developed fluorescence probe shows potential for application in detecting tetracycline in real water samples. [ABSTRACT FROM AUTHOR]

• Novel Li 6 ALa 2 Sb 2 O 12 :Sm3+ (A = Ca and Sr) garnet phosphors are prepared. • The obtained garnet phosphors are cubic structures in the Ia-3d space group. • Concentration quenching is dominated by the dipole-dipole interaction. • Color purity is larger than 80 %. • The obtained phosphors showcase good thermal stability (> 60 % at 423 K). Single-cubic-phase garnet phosphors of the trivalent samarium (Sm3+)-doped Li 6 CaLa 2 Sb 2 O 12 and Li 6 SrLa 2 Sb 2 O 12 matrices were investigated with respect to their crystal structure, morphology, and photoluminescence properties. The concentration quenching mechanism dominated by the dipole-dipole interaction determined the 5 mol% Sm3+ as the optimal doping concentration for the Li 6 ALa 2 Sb 2 O 12 :Sm3+ (A = Ca and Sr) garnet phosphors. As such, the performance comparison was carried out between Li 6 CaLa 2 Sb 2 O 12 :0.05Sm3+ and Li 6 SrLa 2 Sb 2 O 12 :0.05Sm3+ garnet phosphors in terms of various aspects (e.g. , photoluminescence emission intensity, color purity, thermal stability, photoluminescence quantum yield, and decay curve). Particularly, the emission intensity of the Li 6 SrLa 2 Sb 2 O 12 :0.05Sm3+ was stronger than the Li 6 CaLa 2 Sb 2 O 12 :0.05Sm3+ phosphor. Interestingly, both Li 6 SrLa 2 Sb 2 O 12 :0.05Sm3+ and Li 6 CaLa 2 Sb 2 O 12 :0.05Sm3+ garnet phosphors exhibited beneficial thermal stability of 67.72 % and 61.67 % at 423 K, respectively. Overall, it is the first report to study and compare the photoluminescence performances of the reddish-orange Li 6 ALa 2 Sb 2 O 12 :Sm3+ (A = Ca and Sr) garnet phosphors. The findings of this work aim to design a thermal-stable garnet phosphor for potential solid-state lighting. [ABSTRACT FROM AUTHOR]

• Schiff bases as selective turn on-off-on fluorescent chemosensors. • Solvatochromic response in various solvents of different polarities. • Colorimetric, sensetive and selective response towards different metal ions like; K +, V3+, Cr3+, Fe3+, Co2+, Ni2+, Cu2+, Se6+, Cd2+, Ba2+, and Hg2+. In recent years, fluorescent probes have been extensively studied as powerful tools for the effective assessment of toxic metal ions due to their high sensitivity, selectivity, capability for real-time and non-invasive monitoring, and versatility. In this paper, novel fluorescent probes based on Schiff bases, namely 2-((1E,2E)-1-(6-chlorobenzo[d]thiazol-2-ylimino)-3-(4-(dimethylamino)phenyl)allyl)phenol (1) and 2-((1E,2E)-3-(4-(dimethylamino)phenyl)-1-(4-methylbenzo[d]thiazol-2-ylimino)allyl)phenol (2) , were synthesized and characterized. The optical properties of these probes were examined across a spectrum of fourteen solvents with varying polarities, revealing significant solvatochromic effects on both absorption and fluorescence spectra. The analysis delineated a discernible difference in dipole moment between electronic ground and excited states, with molecules exhibiting enhanced stabilization in singlet excited states. Subsequently, a straightforward method was devised for the selective and sensitive detection of diverse metal ions in aqueous solutions, including K+, V3+, Cr3+, Fe3+, Co2+, Ni2+, Cu2+, Se6+, Cd2+, Ba2+, and Hg2+, through naked eye observation, UV–Visible, and fluorimetric measurements. Notably, the UV–Vis spectra of probes 1 and 2 manifested a significant red shift upon the addition of metal ions, indicative of potential ligand-to-metal charge-transfer (LMCT) phenomena, with the exception of Ni2+, Cu2+, and Se6+ions. The observed alterations in optical absorption and fluorescence emission contributed to the probes' heightened selectivity and sensitivity, obviating the necessity for sample pretreatment. Competitive assays underscored the probes' preference for Cr3+ and V3+ ions over other common metal ions. Furthermore, Job's plot analysis suggested a 1:1 ligand-to-metal molar ratio binding. The investigated Schiff bases exhibited elevated binding constants (K a), low detection limits, and limits of quantification, alongside diminished fluorescence quantum yield. Leveraging fluorescence quenching, facile paper-based sensor strips coated with Schiff bases facilitated prompt, qualitative, and quantitative in situ detection of metal ions in aqueous solutions across a broad concentration spectrum, discernible to the naked eye under UV light. [ABSTRACT FROM AUTHOR]

[Display omitted] • Luminescent carbon dots (CDs) offer unique properties for versatile applications. • CDs are widely used in bioimaging, drug delivery, photocatalysis, and sensing. • Surface functionalization enhances CDs' stability and biocompatibility. • Recent advancements address low quantum yield and light stability issues. • Future research aims to optimize CDs for broader applications. Carbon dots (CDs) have become widely recognized for their distinct attributes and possible uses in a variety of areas, leading to increased interest over the last few years. CDs are usually smaller than 10 nm in diameter and are composed of carbon atoms organized in either a crystalline or amorphous form. The synthesis of CDs can be achieved through various methods, including bottom-up and top-down approaches. The bottom-up approach includes hydrothermal, microwave, and pyrolysis synthesis, while the top-down approach includes electrochemical and laser ablation methods. These methods result in CDs with different sizes, surface functional groups, and optical properties. Techniques such as transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) are frequently employed to examine the morphology, structure, and chemical composition of CDs. Additionally, the primary problems and obstacles related to CDs are reviewed, along with efforts to advance the related research fields. CDs have demonstrated potential uses in areas including bioimaging, drug delivery, photocatalysis, and sensors. Their exceptional optical characteristics, compatibility with living organisms, and minimal harmful effects on health make them perfect candidates for utilization in biological and environmental applications. In summary, CDs have a broad scope of potential uses and are considered a versatile category of nanoparticles. More investigation is required to examine their characteristics and improve their production processes for particular applications. [ABSTRACT FROM AUTHOR]

This study presents a novel investigation of the structure, particle morphology and photoluminescence (PL) characteristics of Gd 1-x OCl:Bi x phosphors prepared by a solid-state reaction method. X-ray diffraction data confirmed the formation of the tetrahedral GdOCl phase. The phosphors emitted peculiar photoluminescence that was dependent on the excitation wavelength, annealing temperature and doping concentration. When undoped GdOCl host was excited at 275 nm, a narrowband ultraviolet B (UVB) was observed at 315 nm. This emission is ascribed to the 8S 7/2 → 6I J transition of Gd3+. After doping with Bi3+, two excitation bands were observed at 275 nm (major excitation) and 336 nm (minor excitation). Exciting Bi3+ doped GdOCl at 275 and 366 nm resulted in two broad emission bands at 455 nm (bluish green) and 428 nm (blue) ascribed to and 3P 0,1 → 1S 0 transitions of Bi3+. The PL peak intensities of these emissions were found to vary with Bi3+ doping concentrations and annealing temperatures. The decay characteristics and photoluminescence quantum yield of the blue photoluminescence were determined, and the mechanism of the blue Bi3+ emission is proposed. [ABSTRACT FROM AUTHOR]

An europium(III) coordination binuclear compound [Eu 2 (o -MBA) 6 (phen) 2 ] (o -MBA = ortho -methylbenzoate, phen = 1,10-phenantroline) has been synthesized and investigated by X-ray diffraction method, thermogravimetric analysis (TGA), infrared (IR) and photoluminescence (PL) spectroscopy. The single crystal X-Ray diffraction measurements show that the compound crystallizes in the triclinic centrosymmetric space group P -1. The PL excitation spectrum displays a broad band between 300 and 420 nm and a number of sharp transitions between 384 and 590 nm, which can be attributed to the Eu3+ 4 f 6 intra-shell excitation transitions. The complex exhibits characteristic narrow, metal-centred emission bands, which are determined by the radiative transitions of the Eu3+ ion, from the first excited non-degenerate 5 D 0 level to the 7 F J (J = 0–4) manifold. The compound shows intense hypersensitive transition 5 D 0 →7 F 2 which dominates the PL emission spectrum. The dipole strengths of the transitions were determined from the emission spectra in terms of Judd-Ofelt (JO) intensity parameters Ω λ (λ = 2, 4). The high intensity bright-red emission of the complex can be attributed to highly polarizable ligands environment and the low site symmetry (Ci) around the lanthanide ions. We suppose that the J -mixing effect in the Eu(III) ions is responsible for enhanced peak maximum of the 5 D 0 →7 F 0 transition. [Display omitted] • A binuclear complex [Eu 2 (o-MBA) 6 (phen) 2 ] has been prepared and characterized by XRD, TGA, IR and PL spectroscopy. • A grown crystals comprise two centrosymmetric similar types binuclear molecules with Ci molecular symmetry. • The Eu 2 (o -MBA) 6 (phen) 2 compound shows a pure bright-red luminescence with the intrinsic quantum yield about 75 %. • The radiative parameters of the complex indicate on a significant potential for applications in photonics. [ABSTRACT FROM AUTHOR]

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 PbCl x 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. • PbCl x shell inventively formed around PbS QDs for passivating the surface defects in all solid glass matrix. • Photoluminescence quantum yield obtained from PbS QDs embedded glasses was as high as 49.3 % in near-infrared band. • Chlorine Passivation of surface defects enhanced resistance to temperature and light irradiation of PbS QDs in glasses. [ABSTRACT FROM AUTHOR]

In recent year, the uses of carbon quantum dots (CQDs) have increased in many fields. Herein we report, synthesis of fluorescent nitrogen doped carbon quantum dots (N-CQDs) by simple and ecofriendly hydrothermal method. The as-synthesized N-CQDs were characterized by various techniques and the quantum yield was also calculated. Then, application of N-CQDs were performed as a sensor for detection of ferric ions (Fe3+) based on static quenching mechanism (turn-off) which occurred due to formation of non-fluorescent complex between N-CQDs and Fe3+ ions. Interestingly, fluorescence intensity of quenched N-CQDs has been significantly recovered (turn-on) by addition of ascorbic acid (AA). The recovery mechanism is based on the redox reaction between Fe3+ ions and AA. Thus, N-CQDs has been used as fluorescence “turn-off-on” sensor for detection of Fe3+ ions and AA. Further this detection system is used for detecting Fe3+ ions in Moringa oleifera and AA in citrus lemon.Graphical abstract: In recent year, the uses of carbon quantum dots (CQDs) have increased in many fields. Herein we report, synthesis of fluorescent nitrogen doped carbon quantum dots (N-CQDs) by simple and ecofriendly hydrothermal method. The as-synthesized N-CQDs were characterized by various techniques and the quantum yield was also calculated. Then, application of N-CQDs were performed as a sensor for detection of ferric ions (Fe3+) based on static quenching mechanism (turn-off) which occurred due to formation of non-fluorescent complex between N-CQDs and Fe3+ ions. Interestingly, fluorescence intensity of quenched N-CQDs has been significantly recovered (turn-on) by addition of ascorbic acid (AA). The recovery mechanism is based on the redox reaction between Fe3+ ions and AA. Thus, N-CQDs has been used as fluorescence “turn-off-on” sensor for detection of Fe3+ ions and AA. Further this detection system is used for detecting Fe3+ ions in Moringa oleifera and AA in citrus lemon. [ABSTRACT FROM AUTHOR]

• LiBO 2 -LiF flux provides crystallization of (Eu , Gd) 1+y Sc 3-y (BO 3) 4 crystals. • Luminescence spectra, lifetime and quantum yield up to 53 % were measured. • The material based on EuSc 3 (BO 3) 4 has high temperature and chemical stability. Solid solutions based on (Eu , Gd)Sc 3 (BO 3) 4 (C2/c) and Gd 0.25 Sc 0.75 BO 3 (R 3 ¯ ) in the EuSc 3 (BO 3) 4 -GdSc 3 (BO 3) 4 system were studied. Synthesis at 1250 °C provides wide homogeneity regions which are stable at room temperature. Melt-solution crystallization of both compounds from LiBO 2 -LiF flux was shown. All the obtained samples have luminescence characteristic of Eu3+ with a largest peak at 615 nm corresponding to the 5D 0 → 7F 2 transition. In this series the luminescence intensity monotonically increases with an increase of Eu content. The largest quantum yield of luminescence (53 %) in the EuSc 3 (BO 3) 4 -GdSc 3 (BO 3) 4 system is demonstrated by EuSc 3 (BO 3) 4 sample. [ABSTRACT FROM AUTHOR]

Active optical materials with intrinsic chirality, in particular, circularly polarized luminescence (CPL), are highly demanded for utilization in data processing, bioimaging, and photocatalytic asymmetric synthesis. Crystal structure engineering, chiral assembly, and chirality imprinting by chiral ligands were proposed for fabrication of CPL-active materials. The former approach is applicable to colloidal perovskite nanocrystals (PNCs), which attract significant attention due to their outstanding optical properties and high tunability. However, the issues of chiral perovskite NC stability, control of the bandgap, and achieving high photoluminescence quantum yield and emission dissymmetry factor simultaneously remain unresolved. To overcome these obstacles, we developed mixed-halide chiral perovskite NCs by simultaneous anion and ligand exchanges, which provide the passivation of surface defects and induce a chiral response. As a result, the chiral PNCs exhibit CPL with dissymmetry factors up to 3.4 × 10−2 and a photoluminescence quantum yield up to 98 %, making the proposed approach promising for chirality imprinting. [Display omitted] • CsPbCl 3 perovskite nanocrystals were post-synthetically treated with R/S-MBA:Br. • R/S-MBA:Br treatment results in simultaneous anion and ligand exchanges. • Treatment induces imprinting of chiroptical responses to perovskite nanocrystals. • Nanocrystals possess PLQY up to 0.98 and CPL dissymmetry factors up to 10−2. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new porphyrin compound (SP) was designed and synthesized as photosensitizer and its structure was clarified by NMR (13C and 1H) and mass spectra. • Photophysical and photochemical properties were examined. • Singlet oxygen quantum yields were obtained as 0.48 and 0.59 by direct and indirect methods, respectively. • Antibacterial activity studies have been conducted within the scope of biological activity and promising results have been obtained under LED light. Considering the increasing number of pathogens resistant to commonly used antibiotics as well as antiseptics, there is an urgent need for antimicrobial approaches that can effectively inactivate pathogens without the risk of establishing resistance. An alternative approach in this context is antibacterial photodynamic therapy (APDT). APDT is a process that involves bacterial cell death using appropriate wavelength light energy and photosensitizer and causes the production of reactive oxygen species inside or outside the microbial cell depending on the penetration of light energy. In our study, a new porphyrin compound 4,4′-methylenebis(2-((E)-((4-(10,15,20-triphenylporphyrin-5-yl)phenyl)imino)methyl)phenol) (SP) was designed and synthesized as photosensitizer and its structure was clarified by NMR (13C and 1H) and mass determination method. Photophysical and photochemical properties were examined in detail using different methods. Singlet oxygen quantum yields were obtained as 0.48 and 0.59 by direct and indirect methods, respectively. Antibacterial activity studies have been conducted within the scope of biological activity and promising results have been obtained under LED light (500–700 nm, 265 V, 1500 LM), contributing to the antibacterial photodynamic therapy literature. [ABSTRACT FROM AUTHOR]

Two novel Tb(III) ternary complexes, [Tb2(Phen)2(p-BrBA)6] and [TbY(Phen)2(p-BrBA)6], have been synthesized with p-bromobenzoic acid(p-BrBA) as the primary ligand and 1,10-phenanthroline(Phen) as the secondary ligand. The structures of these complexes are characterized by elemental analysis, IR spectroscopy, UV-vis absorption spectroscopy, thermal analysis (TGA) and single-crystal X-ray diffraction. The crystal structures of the compounds are similar because of similar radii of Tb3+ ion and Y3+ ion. Both the homobimetallic single crystal and the heterobimetallic single crystal belong to the monoclinic system. The results show that both complexes have excellent luminescence properties, including luminescent intensity, luminescent lifetime and quantum yield. The two compounds have an excited state lifetime of milliseconds and the photoluminescence quantum efficiencies of the two terbium complexes can exceed 100% upon excitation to their 5d states in theory, which is attributed to luminescent lifetime and quantum cutting (QC). Furthermore, the luminescent properties of [TbY(Phen)2(p-BrBA)6] are actually superior to those of [Tb2(Phen)2(p-BrBA)6]. [ABSTRACT FROM AUTHOR]

In this work, we reported the synthesis of carbon quantum dots (CQDs) with high fluorescent quantum yield (90.7 %). These nanoparticles were applied in a turn-off/turn-on sensor able to detect cyanide ions. In this sensing strategy, Fe3+ ions were added to the aqueous suspension of CQDs to quench the fluorescence of the system, which was recovered from the presence of cyanide ions. Furthermore, a sensor array was developed using the LDA chemometric tool, to classify different species present in cookie formulations, including gluten. The turn-off/turn-on sensor proved to be sensitive and effective for detecting cyanide ions, with a detection limit of 3.77 ppm. This high sensibility and selectivity allowed quantifying the analyte in a real sample of tap water. [Display omitted] • A fluorescent nanoprobe with ultra-high quantum yield (90.7 %) for sensing of allergens and toxic substances was obtained. • Carbon Quantum Dots (CD-90) synthesized by one-step hydrothermal treatment and showed high fluorescence signal at 440 nm. • CD-90 were used as fluorescent nanoprobes in the construction of a sensor array for detection of gluten in cookies samples. • Fe3+ ions quenched the fluorescence of CD-90, which was recovery by adding CN − ions. • CN − ions were identified in tap water sample with recovery of 94.8 % and RSD of 7.34 %. [ABSTRACT FROM AUTHOR]

Abstract Background Quantum dots (QDs) have been used as fluorophores in various imaging fields owing to their strong fluorescent intensity, high quantum yield (QY), and narrow emission bandwidth. However, the application of QDs to bio-imaging is limited because the QY of QDs decreases substantially during the surface modification step for bio-application. Results In this study, we fabricated alloy-typed core/shell CdSeZnS/ZnS quantum dots (alloy QDs) that showed higher quantum yield and stability during the surface modification for hydrophilization compared with conventional CdSe/CdS/ZnS multilayer quantum dots (MQDs). The structure of the alloy QDs was confirmed using time-of-flight medium-energy ion scattering spectroscopy. The alloy QDs exhibited strong fluorescence and a high QY of 98.0%. After hydrophilic surface modification, the alloy QDs exhibited a QY of 84.7%, which is 1.5 times higher than that of MQDs. The QY was 77.8% after the alloy QDs were conjugated with folic acid (FA). Alloy QDs and MQDs, after conjugation with FA, were successfully used for targeting human KB cells. The alloy QDs exhibited a stronger fluorescence signal than MQD; these signals were retained in the popliteal lymph node area for 24 h. Conclusion The alloy QDs maintained a higher QY in hydrophilization for biological applications than MQDs. And also, alloy QDs showed the potential as nanoprobes for highly sensitive bioimaging analysis. Graphical Abstract

Abstract Aiming at the low luminous‐efficiency of two‐dimensional (2D) perovskite, its quantum yield (QY) and stability are effectively improved by a fluorinated second insulator layer 3,4‐difluoroaniline (F2PA) outside of the first insulator 2‐(2,4‐difluorophenyl) ethylamine (FPEA). The QY of perovskite with two insulator layers is improved by 3.4‐time in contrast with its counterpart with one insulator, which originates from the defect suppression and reduction of exciton Bohr radius by the second layer. The optical stability has extended 1.5‐time by the introduced second layer, as an isolation role for inner decomposed products to volatilize and for outer water molecules to penetrate. The perovskite with two insulator layers retained 90% of its initial optical properties in relative humidity 90%–95% atmosphere for 600 h, meanwhile only 50% for its counterpart with one layer. Two‐more fluorine with stronger hydrophobicity can account for this feature. Adding a second insulator layer is an effective strategy to engineer 2D perovskites and push forward its applications in optoelectronic devices.