Crystalline Domain Size Research Articles

Preparation of High-quality Vapor-deposited Crystalline Organic Thin Films through Crystallization from Their Liquid Crystal Phase

High-quality crystalline organic thin films with large crystalline domain size were fabricated by vacuum deposition, followed by a post-annealing and cooling crystallization from their respective smectic A (SmA) liquid crystal precursor states. Crystallinity, surface smoothness and air exposure stability of ionic liquid crystalline thin films were much improved by this process, and the electric double layer action was for the first time observed at the SmA phase. Moreover, a seeded temperature gradient cooling process from the SmA phase was proposed and its capability was demonstrated in the fabrication of benzothienobenzothiophene derivative thin films, achieving their directional lateral crystal growth with high precision controllability.

Recrystallization of MBE‐Grown MoS2 Monolayers Induced by Annealing in a Chemical Vapor Deposition Furnace

A systematic study of MoS2 grown by a combination of physical vapor deposition and post‐growth annealing treatment has been conducted. Hereby, MoS2 thin films with thicknesses between 1 and 2 layers are first grown on sapphire by molecular beam epitaxy at different growth temperatures and then transferred to S environment inside a tube furnace for an annealing process. Depending on the growth temperature, the as‐grown layers are either amorphous or form a crystalline structure composed of closely packed nanometer‐size grains. The annealing process leads to recrystallization of these layers significantly increasing the size of the MoS2 crystalline domains to the range of 50–100 nm. While the originally amorphous layer displays rotational domains after annealing, recrystallization of samples grown at high temperatures yields single crystalline layers. All samples display an increase of the crystallite dimension, which is accompanied by the disappearance of the defect‐related peaks in the Raman spectra, sharpening of the excitonic signatures in absorption, and strong enhancement of the photoluminescence yield. The results represent a promising way to combine advantages of physical vapor deposition and a post‐growth annealing in a chemical vapor deposition furnace toward fabrication of wafer‐scale single crystalline transition metal dichalcogenide mono‐ and multilayer films on non‐van der Waals substrates.

Power Efficiency Enhancement of Organic Light-Emitting Diodes Due to the Favorable Horizontal Orientation of a Naphthyridine-Based Thermally Activated Delayed Fluorescence Luminophore.

Four emitters based on the naphthyridine acceptor moiety and various donor units exhibiting thermally activated delayed fluorescence (TADF) were designed and synthesized. The emitters exhibited excellent TADF properties with a small ΔE ST and a high photoluminescence quantum yield. A green TADF organic light-emitting diode based on 10-(4-(1,8-naphthyridin-2-yl)phenyl)-10H-phenothiazine exhibited a maximum external quantum efficiency of 16.4% with Commission Internationale de L'éclairage coordinates of (0.368, 0.569) as well as a high current and power efficiency of 58.6 cd/A and 57.1 lm/W, respectively. The supreme power efficiency is a record-high value among the reported values of devices with naphthyridine-based emitters. This results from its high photoluminescence quantum yield, efficient TADF, and horizontal molecular orientation. The molecular orientations of the films of the host and the host doped with the naphthyridine emitter were explored by angle-dependent photoluminescence and grazing-incidence small-angle X-ray scattering (GIWAXS). The orientation order parameters (ΘADPL) were found to be 0.37, 0.45, 0.62, and 0.74 for the naphthyridine dopants with dimethylacridan, carbazole, phenoxazine, and phenothiazine donor moieties, respectively. These results were also proven by GIWAXS measurement. The derivative of naphthyridine and phenothiazine was shown to be more flexible to align with the host and to show the favorable horizontal molecular orientation and crystalline domain size, benefiting the outcoupling efficiency and contributing to the device efficiency.

Synthesis by soft chemistry of size-controlled zinc oxide (ZnO) nanocrystals for antimicrobial applications

This work focuses on the synthesis of ZnO nanoparticles (NPs) by the sol-gel method for antimicrobial applications. The influence of synthesis parameters on the size of NPs is discussed. The addition of water and an alcoholamine (Monoethanolamine MEA) during the synthesis made possible the crystallization of ZnO at low temperature (<110°C). Our experiments have also shown that these reagents exert an influence on the size of the NPs. The NPs after precipitation are recovered in the form of powders then characterized by different techniques: X-ray diffraction (XRD) and Raman spectroscopy. The crystalline domain size are calculated from Scherrer’s formula. The antimicrobial potential of these NPs has been studied. The technique applied for this evaluation consists in estimating the minimum inhibitory concentration (MIC) of the NPs by measuring the evolution of the optical density of the bacteria over time. The results showed that the synthesized ZnO NPs show efficacy on the Escherichia coli bacteria.

Composite CdS/TiO2 Powders for the Selective Reduction of 4-Nitrobenzaldehyde by Visible Light: Relation between Preparation, Morphology and Photocatalytic Activity

A series of composite CdS/TiO2 powders was obtained by nucleation of TiO2 on CdS nanoseeds. This combination presents the appropriate band edge position for photocatalytic redox reactions: visible light irradiation of CdS allows the injection of electrons into dark TiO2, increasing the lifetimes of separated charges. The electrons have been used for the quantitative photoreduction of 4-nitrobenzaldehyde to 4-aminobenzaldehyde, whose formation was pointed out by 1H NMR and ESI-MS positive ion mode. Concomitant sacrificial oxidation of 2-propanol, which was also the proton source, occurred. The use of characterization techniques (XRD, N2 adsorption-desorption) evidenced the principal factors driving the photocatalytic reaction: the nanometric size of anatase crystalline domains, the presence of dispersed CdS to form an extended active junction CdS/anatase, and the presence of mesopores as nanoreactors. The result is an efficient photocatalytic system that uses visible light. In addition, the presence of TiO2 in combination with CdS improves the stability of the photoactive material, enabling its recyclability.

Scaffold-Enforced Nanoscale Crystalline Order Supersedes Interfacial Interactions in Driving CsPbI3 Perovskite Phase Stability

The equilibrium phase of cesium lead iodide (CsPbI3) is a high-density, low-symmetry, yellow crystalline solid below 320 °C, above which it transitions to the optoelectronically functional, black, perovskite phase. Several reports have achieved lowered phase transition temperatures and increased metastability of perovskite-phase CsPbI3 and attributed the effect variably to reduced size, surface-induced strain, and/or external additives. While theory supports that both reduced size and substrate-induced strain can tilt the competition between surface and bulk energies to favor the perovskite phase, there has not been a study of the relative influence of size and interfacial interactions on these dynamics. In this study, we selectively varied crystalline domain size by embedding CsPbI3 in open nanoporous titania scaffolds composed of particles ranging from 20 to 200 nm and measured the influence on phase transition behavior. We modified the surface of the scaffold using polar, ionizable, and nonpolar silane self-assembled monolayers (SAMs) to systematically test the extent to which the chemical identity of the interface impacts the surface energy contribution to the phase stability in the perovskite-scaffold composite. While structural and functional consequences were observed for different interfacial chemistries, there was no significant influence on phase equilibrium, and the disruption of long-range crystalline order alone was found to be sufficient to depress the phase transition temperature by more than 250 °C compared to bulk.

Decoupling electrochemical parameters of molecular-level-controlled polypyrrole and graphene oxide nanocomposite

A molecular-level-controlled polypyrrole from a predoped two-monomer-connected precursor (TMCP) and graphene oxide (GO) nanocomposite is synthesized for an active electrode. TMCP (Py:NDSA:Py) consists of two pyrrole monomer, in which bifunctional naphthalene disulfonic acid (NDSA) acts as a protonic dopant and connector. Four molecular-level-controlled P(Py:NDSA:Py)/GO-based nanocomposites are formed when Py:NDSA:Py is polymerized on the hydrophilic GO surface with 100, 75, 50, and 25 mol % of NDSA. The resulting P(Py:NDSA100:Py)/GO nanocomposite exhibits excellent electrochemical performance and cycling stability. A systematic investigations of molecular-level-controlled P(Py:NDSA100:Py)/GO nanocomposite shows that various parameters such as relatively high crystallinity (47.2 %), crystalline domain size (24.2 nm), high doping level (35 %), and electrical conductivity (23.6 S/cm) could be well controlled using a 100 mol % of NDSA connector. An optimized P(Py:NDSA100:Py)/GO nanocomposite with 20 wt% GO significantly improves the specific capacitance of 306 F g−1 at a current density of 1 A g−1 and excellent cycling stability of 75 % up to 2000 cycles without using carbon supplement (carbon black). This systematic decoupling of electrochemical parameters of molecular-level-controlled polypyrrole nanocomposites can serve as an approach for rational design with tailored properties of other polymeric nanocomposites for electrochemical applications.

Identifying optimal dispersant aids for flame retardant additives in tetramethyl cyclobutanediol‐based copolyesters

AbstractProper dispersion of an additive throughout a polymer matrix is essential to achieving the desired effects of the additive. Typically, this dispersion is difficult due to poor interactions between the polymer and additive. In the case of melamine cyanurate (MC), an extensive hydrogen bonding network among the principal components results in large domains that prevent it from adequately dispersing within many polymer matrices. Adding a hydrogen bonding capable polymer that competes with intramolecular hydrogen bonding of the MC may lead to a reduction in MC domain size. The disruption of intramolecular MC hydrogen bonding was monitored with attenuated total reflection Fourier transform infrared spectroscopy, while crystalline domain size was determined with scanning electron microscopy. Water‐soluble polymers are identified as an ideal category of dispersing aids for their hydrogen bonding ability and compatibility with melamine cyanurate. Disrupting the hydrogen bonding network on an atomic level with a water‐soluble polymer dispersant led to at least a 50% reduction in measured particle size, as well as in increase in the domain size's homogeneity, as indicated by a 75% reduction in the polydispersity of particle sizes in melt mix samples.

Effects of cholesterol on the structure and collapse of DPPC monolayers

Cholesterol induces faster collapse by compressed films of pulmonary surfactant. Because collapse prevents films from reaching the high surface pressures achieved in the alveolus, most therapeutic surfactants remove or omit cholesterol. The studies here determined the structural changes by which cholesterol causes faster collapse by films of dipalmitoyl phosphatidylcholine, used as a simple model for the functional alveolar film. Measurements of isobaric collapse, with surface pressure held constant at 52 mN/m, showed that cholesterol had little effect until the mol fraction of cholesterol, Xchol, exceeded 0.20. Structural measurements of grazing incidence X-ray diffraction at ambient laboratory temperatures and a surface pressure of 44 mN/m, just below the onset of collapse, showed that the major structural change in an ordered phase occurred at lower Xchol. A centered rectangular unit cell with tilted chains converted to an untilted hexagonal structure over the range of Xchol = 0.0–0.1. For Xchol = 0.1–0.4, the ordered structure was nearly invariant; the hexagonal unit cell persisted, and the spacing of the chains was essentially unchanged. That invariance strongly suggests that above Xchol = 0.1, cholesterol partitions into a disordered phase, which coexists with the ordered domains. The phase rule requires that for a binary film with coexisting phases, the stoichiometries of the ordered and disordered regions must remain constant. Added cholesterol must increase the area of the disordered phase at the expense of the ordered regions. X-ray scattering from dipalmitoyl phosphatidylcholine/cholesterol fit with that prediction. The data also show a progressive decrease in the size of crystalline domains. Our results suggest that cholesterol promotes adsorption not by altering the unit cell of the ordered phase but by decreasing both its total area and the size of individual crystallites.

Environmental stress cracking of polyethylene pipe: Changes in physical structures leading to failure

The environmental stress cracking resistance (ESCR) was studied for pipe made of bimodal poly(ethylene-co-1-butene) copolymer. Ductile or brittle failures of the pipe were observed after pipe exposure to different temperatures and hydrostatic pressures. Changes in the phase composition, size of crystalline and amorphous domains and molecular mobility were studied in failed test pipes by DSC, SAXS, solid-state 13C NMR spectroscopy and time-domain 1H NMR T2 relaxometry. The ESCR test at 20 °C causes a decrease in crystallinity, which suggests lamellar fragmentation, whereas a slight crystallinity increase is observed at a test temperature of 70 °C. At both temperatures, molecular mobility in the amorphous phase decreases, suggesting stress-induced elongation of chain segments in the amorphous phase. ESCR tests at 95 and 110 °C led to crystallinity increases and lamellar thickening owing to partial melting and recrystallization during long-term pipe exposure to high temperatures. The test causes an increase in molecular mobility in the amorphous phase due to a change in partitioning of ethyl chain branches between the crystal-amorphous interface and the amorphous phase. The role of molecular mobility in the amorphous phase on the type of failure and on reorganization of semicrystalline morphology during the ESCR test is discussed.

Combination of Knoevenagel Polycondensation and Water-Assisted Dynamic Michael-Addition-Elimination for the Synthesis of Vinylene-Linked 2D Covalent Organic Frameworks.

Vinylene‐linked two‐dimensional conjugated covalent organic frameworks (V‐2D‐COFs), belonging to the class of two‐dimensional conjugated polymers, have attracted increasing attention due to their extended π‐conjugation over the 2D backbones associated with high chemical stability. The Knoevenagel polycondensation has been demonstrated as a robust synthetic method to provide cyano (CN)‐substituted V‐2D‐COFs with unique optoelectronic, magnetic, and redox properties. Despite the successful synthesis, it remains elusive for the relevant polymerization mechanism, which leads to relatively low crystallinity and poor reproducibility. In this work, we demonstrate the novel synthesis of CN‐substituted V‐2D‐COFs via the combination of Knoevenagel polycondensation and water‐assisted dynamic Michael‐addition‐elimination, abbreviated as KMAE polymerization. The existence of C=C bond exchange between two diphenylacrylonitriles (M1 and M6) is firstly confirmed via in situ high‐temperature NMR spectroscopy study of model reactions. Notably, the intermediate M4 synthesized via Michael‐addition can proceed the Michael‐elimination quantitatively, leading to an efficient C=C bond exchange, unambiguously confirming the dynamic nature of Michael‐addition‐elimination. Furthermore, the addition of water can significantly promote the reaction rate of Michael‐addition‐elimination for highly efficient C=C bond exchange within 5 mins. As a result, the KMAE polymerization provides a highly efficient strategy for the synthesis of CN‐substituted V‐2D‐COFs with high crystallinity, as demonstrated by four examples of V‐2D‐COF‐TFPB‐PDAN, V‐2D‐COF‐TFPT‐PDAN, V‐2D‐COF‐TFPB‐BDAN, and V‐2D‐COF‐HATN‐BDAN, based on the simulated and experimental powder X‐ray diffraction (PXRD) patterns as well as N2‐adsorption–desorption measurements. Moreover, high‐resolution transmission electron microscopy (HR‐TEM) analysis shows crystalline domain sizes ranging from 20 to 100 nm for the newly synthesized V‐2D‐COFs.

Combination of Knoevenagel Polycondensation and Water‐Assisted Dynamic Michael‐Addition‐Elimination for the Synthesis of Vinylene‐Linked 2D Covalent Organic Frameworks

AbstractVinylene‐linked two‐dimensional conjugated covalent organic frameworks (V‐2D‐COFs), belonging to the class of two‐dimensional conjugated polymers, have attracted increasing attention due to their extended π‐conjugation over the 2D backbones associated with high chemical stability. The Knoevenagel polycondensation has been demonstrated as a robust synthetic method to provide cyano (CN)‐substituted V‐2D‐COFs with unique optoelectronic, magnetic, and redox properties. Despite the successful synthesis, it remains elusive for the relevant polymerization mechanism, which leads to relatively low crystallinity and poor reproducibility. In this work, we demonstrate the novel synthesis of CN‐substituted V‐2D‐COFs via the combination of Knoevenagel polycondensation and water‐assisted dynamic Michael‐addition‐elimination, abbreviated asKMAEpolymerization. The existence of C=C bond exchange between two diphenylacrylonitriles (M1andM6) is firstly confirmed via in situ high‐temperature NMR spectroscopy study of model reactions. Notably, the intermediateM4synthesized via Michael‐addition can proceed the Michael‐elimination quantitatively, leading to an efficient C=C bond exchange, unambiguously confirming the dynamic nature of Michael‐addition‐elimination. Furthermore, the addition of water can significantly promote the reaction rate of Michael‐addition‐elimination for highly efficient C=C bond exchange within 5 mins. As a result, theKMAEpolymerization provides a highly efficient strategy for the synthesis of CN‐substituted V‐2D‐COFs with high crystallinity, as demonstrated by four examples of V‐2D‐COF‐TFPB‐PDAN, V‐2D‐COF‐TFPT‐PDAN, V‐2D‐COF‐TFPB‐BDAN, and V‐2D‐COF‐HATN‐BDAN, based on the simulated and experimental powder X‐ray diffraction (PXRD) patterns as well as N2‐adsorption–desorption measurements. Moreover, high‐resolution transmission electron microscopy (HR‐TEM) analysis shows crystalline domain sizes ranging from 20 to 100 nm for the newly synthesized V‐2D‐COFs.

Microstructure and lattice defects in highly deformed metals by X-ray diffraction whole powder pattern modelling

AbstractBasic principles and recent developments of the Whole Powder Pattern Modelling (WPPM) approach are briefly reviewed and illustrated by a typical case study: a highly deformed metal powder (AISI 434) produced by high energy ball milling. Microstructural parameters, like crystalline domain size distribution, dislocation density, and arrangement parameters, are directly obtained by modelling the experimental pattern, without using arbitrary analytical profile functions.

Plasma‐Induced Nanocrystalline Domain Engineering and Surface Passivation in Mesoporous Chalcogenide Semiconductor Thin Films

AbstractThe synthesis of highly crystalline mesoporous materials is key to realizing high‐performance chemical and biological sensors and optoelectronics. However, minimizing surface oxidation and enhancing the domain size without affecting the porous nanoarchitecture are daunting challenges. Herein, we report a hybrid technique that combines bottom‐up electrochemical growth with top‐down plasma treatment to produce mesoporous semiconductors with large crystalline domain sizes and excellent surface passivation. By passivating unsaturated bonds without incorporating any chemical or physical layers, these films show better stability and enhancement in the optoelectronic properties of mesoporous copper telluride (CuTe) with different pore diameters. These results provide exciting opportunities for the development of long‐term, stable, and high‐performance mesoporous semiconductor materials for future technologies.

Plasma-Induced Nanocrystalline Domain Engineering and Surface Passivation in Mesoporous Chalcogenide Semiconductor Thin Films.

The synthesis of highly crystalline mesoporous materials is key to realizing high‐performance chemical and biological sensors and optoelectronics. However, minimizing surface oxidation and enhancing the domain size without affecting the porous nanoarchitecture are daunting challenges. Herein, we report a hybrid technique that combines bottom‐up electrochemical growth with top‐down plasma treatment to produce mesoporous semiconductors with large crystalline domain sizes and excellent surface passivation. By passivating unsaturated bonds without incorporating any chemical or physical layers, these films show better stability and enhancement in the optoelectronic properties of mesoporous copper telluride (CuTe) with different pore diameters. These results provide exciting opportunities for the development of long‐term, stable, and high‐performance mesoporous semiconductor materials for future technologies.

Obtaining of hematite from industrial steel waste using dry-milling and high temperature

In this work, the mill scale (MS) of hot rolling, a waste of steel processing, composed by a complex mixture of iron oxides, is transformed in a nanocrystalline powder containing only the hematite (α-Fe 2 O 3 ) phase. For that, the MS was dry-milled using a high-energy ball mill for 30 min and heat-treated up to 1200 °C for 25 min. The samples of this study were characterized by X-ray diffraction, Thermogravimetric Analysis and Vibrating Sample Magnetometry. The milling process decreases the amount of FeO phase content (FeO:Fe 3 O 4 phase ratio from 3:1 to 1:1), reduces the average crystallite size and increases the micro-strain of the iron oxides. The high-temperature experiments showed the complete transformation of the Fe 3 O 4 and FeO nanophases to the nanocrystalline α-Fe 2 O 3 with average crystalline domains greater than 180 nm after few hours of heat treatment. The thermal expansion coefficient of the α-Fe 2 O 3 nanophase was obtained considering anisotropic effects, mainly for the a -axis. Thermogravimetric analysis shows the oxidation of Fe 3 O 4 to α-Fe 2 O 3 . The milled MS sample shows a mixed magnetism that transforms to a weak ferromagnetism (or antiferromagntism) after thermal treatment. The temperature of the Morin transition of the α-Fe 2 O 3 nanophase at 110 K and a second magnetic transition at 50 K, related to a spin-glass state, seems to be strongly affected by the nanometric size of crystalline domains (about 180 nm).

Selective synthesis of tungsten carbide phases W2C and WC as hydrogenation catalysts

Tungsten carbides are possible low-cost replacements for noble metal catalysts, but the role of different carbide stoichiometries (W2C, WC) and their polymorphs for catalytic behavior is poorly understood. We develop a “dynamic, isothermal” carburization of WO3 in a mixture of CH4 and H2 to control phase composition and catalytic properties. A design-of-experiments approach reveals that the key parameters are synthesis temperature (670 to 775 °C) and addition of silica as stabilizer (0 or 70 mol%). X-ray diffraction shows that the composition can be adjusted from 14 to 99 wt% W2C, complemented by WC and a small fraction of W metal. Crystalline domain sizes for W2C are smaller than those of WC (≥10 nm), affording thermodynamic stabilization of W2C in agreement with computational predictions (Shrestha et al., Chem. Mater. 2021, 33, 4606–4620). The amount of CO adsorbed scales with W2C content, and so does the performance in butyraldehyde or toluene hydrogenation.

Effect of Pristine Graphene on Methylammonium Lead Iodide Films and Implications on Solar Cell Performance

The relatively low stability of solar cells based on hybrid halide perovskites is the main issue to be solved for the implementation in real life of these extraordinary materials. Degradation is accelerated by temperature, moisture, oxygen, and light and mediated by halide easy hopping. The approach here is to incorporate pristine graphene, which is hydrophobic and impermeable to gases and likely limits ionic diffusion while maintaining adequate electronic conductivity. Low concentrations of few-layer graphene platelets (up to 24 × 10–3 wt %) were incorporated to MAPbI3 films for a detailed structural, optical, and transport study whose results are then used to fabricate solar cells with graphene-doped active layers. The lowest graphene content delays the degradation of films with time and light irradiation and leads to enhanced photovoltaic performance and stability of the solar cells, with relative improvement over devices without graphene of 15% in the power conversion efficiency, PCE. A higher graphene content further stabilizes the perovskite films but is detrimental for in-operation devices. A trade-off between the possible sealing effect of the perovskite grains by graphene, that limits ionic diffusion, and the reduction of the crystalline domain size that reduces electronic transport, and, especially, the detected increase of film porosity, that facilitates the access to atmospheric gases, is proposed to be at the origin of the observed trends. This work demonstrated how the synergy between these materials can help to develop cost-effective routes to overcome the stability barrier of metal halide perovskites, introducing active layer design strategies that allow commercialization to take off.

Microstructural Activation of a Topochemical Reduction Reaction.

The progress of the topochemical reduction reaction that converts LaSrNiRuO6 into LaSrNiRuO4 depends on the synthesis conditions used to prepare the oxidized phase. Samples of LaSrNiRuO6 that have been quenched from high temperature can be readily and rapidly converted into LaSrNiRuO4. In contrast, samples that have been slow-cooled cannot be completely reduced. This reactivity difference is attributed to the differing microstructures of the quenched and slow-cooled samples, with the former having much smaller average crystalline domain sizes and larger lattice strains than the latter. A mechanism to explain this effect is presented, in which the greater "plasticity" of small crystalline domains helps lower the activation energy of the reduction reaction. In addition, we propose that the enhanced lattice strain in quenched samples also acts to destabilize the host phase, further enhancing reactivity. These observations suggest that the microstructure of a material can be used to "activate" topochemical reactions in the solid state, expanding the scope of phases that can be prepared by this type of reaction.

Facile synthesis of nano-sized zinc-rich ZnCdS ternary alloy and UV-irradiation curing of photoluminescence emission characteristics

Zn-rich ZnCdS nanoparticles (NPs) are successfully synthesized by a facile chemical co-precipitation technique at room temperature. The crystal structure homogeneity of the as-synthesized ternary alloy is examined by the x-ray diffraction pattern and the micro-Raman spectroscopy. The average crystalline domain size is about 4 nm indicating the spatial particle confinement of ternary ZnCdS NPs. The optical bandgap (Eg) of the as-synthesized ZnCdS NPs is 3.95 eV that is higher than the corresponding ternary bulk alloy due to the improvement in the quantum size effect. The effect of UV irradiation on the optical band gap of ZnCdS NPs is investigated at different exposure times. A strong decrease in Eg is observed with increasing exposure time up to 60 min followed by Eg saturation at higher UV exposure times. The as-synthesized ZnCdS nanopowder exhibits a wide emission spectrum extending from UV to visible spectral region, which originating from various intrinsic structural defects. The aging of the as-synthesized ZnCdS nanopowder results in emission intensity quenching without changing peak positions. The emission intensity is recovered by the direct exposure to UV irradiation. This indicates the ability of UV irradiation to cure the emission characteristics of small NPs. This would provide more durability about the emission characteristics of the ZnCdS NPs-based fluorescence sensor.