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Zinc selenide (ZnSe) thin films were deposited on non-conducting glass substrates at different selenium concentrations using a photo-assisted chemical bath deposition method. The films were deposited for 2.0 h at 80 °C and annealed for 2.0 h at 250 °C. X-ray diffraction (XRD) revealed a hexagonal structure with preferential orientation along the (002) plane, and the crystallite sizes were about 9–11 nm. Raman scattering showed longitudinal optical phonon modes due to the ZnSe, and the effect of the selenium concentration was noticed on the peak intensities of the XRD and Raman scattering studies. Optical analysis showed higher absorbance in the visible region than near the infrared spectrum, making the thin films good materials for selective absorber surfaces. The estimated bandgap ranged between 2.37 and 2.70 eV. X-ray spectroscopy confirmed the presence of the desired elements and revealed that the ratio of selenium to zinc declined after the sample was prepared with 0.6 M selenium ions. Photoluminescence studies revealed three emission peaks, which were due to defect state levels in the ZnSe. By varying the selenium concentration, the ZnSe was tuned to a reddish color emission, as confirmed by Commission Internationale de L'Eclairage (CIE) color chromaticity analysis. The selective absorption, wide bandgap, and emission properties suggest that the material is promising for light-emitting device applications. [ABSTRACT FROM AUTHOR]

The work is devoted to the study of the second-harmonic generation (SHG) process as a result of random quasi-phase-matching of thulium laser radiation in ZnSe polycrystals. A linear dependence of the SHG efficiency on the nonlinear medium length has been observed in the experiment. The efficiencies of SHG in ZnSe polycrystals with average grain sizes from 35 μ m to 380 μ m were compared. The obtained results are in good agreement with the theory in the case of a Gaussian grain size distribution. [ABSTRACT FROM AUTHOR]

This treatise showcases the design as well as modeling about a photodetector (PD) based on AgInSe2 (AISe), a direct bandgap chalcopyrite with a bandgap of 1.19 eV. The PD exhibits outstanding optical and electronic characteristics, showcasing remarkable performance. The PD has been systematically investigated by varying the width, carrier density, and defect densities of specific layers, as well as the interface defect density of specific interfaces. Various layers are optimized to enhance the overall performance of the PD and the impact of different device resistances is analyzed. The photocurrent (JSC) and voltage (VOC) of the heterostructure photodetector are determined to be 38.60 mA/cm2 and 1.0 V, in turn. The maximum responsivity (R) and detectivity (D*) are identified as 0.70 A/W and 4.60 × 1016 Jones, respectively at a wavelength of 940 nm. The spectral response exhibits significantly higher values in the range of 800–1000 nm, indicating the device's capability to detect near‐infrared (NIR) light. This research provides valuable insights for the manufacturing of AISe material‐based photodetectors with enhanced performance. [ABSTRACT FROM AUTHOR]

ZnSe thin films were deposited on nonconducting glass substrates using different Zn2+ ion concentrations. The films were deposited at 80∘C for 2.0h via photo-assisted chemical bath technique and annealed for 2.0h at 250∘C. X-ray diffraction revealed a hexagonal structure with preferred orientation along the (002) plane and the average crystallite size decreased from 10.5nm to 6.8nm with increased Zn2+ ions. Raman spectra were used to confirm ZnSe phonon modes whose intensity increased with Zn2+ ion concentrations although with fluctuation. Optical analysis showed higher absorbance and low transmittance in the visible region than near infrared making the thin films good materials for selective absorber surfaces. The band gap increased from 2.52eV to 2.78eV as the Zn2+ ion concentration varied from 0.05% to 0.25%. The presence of the desired elements was confirmed by the EDS. Photoluminescence studies revealed three emission peaks which were all ascribed to defect state levels in ZnSe and all the samples emitted in reddish color according to CIE color chromaticity analysis. The selective absorption, wide band gap and broad emission properties suggest that the material is promising for optoelectronic applications. [ABSTRACT FROM AUTHOR]

This research is devoted to the fabrication of zinc selenide nanostructures using the pulsed laser deposition (PLD) technique in a vacuum under a pressure of 2. 5 × 1 0 − 2 mbar. The structure and structural properties were studied, as it was observed that it had polycrystalline structures and showed peaks for zinc and selenium and peaks belonging to the compound zinc selenide. As for the morphological characteristics of the nanostructures, the structures showed the nature of the surface and the roughness to identify its surface properties. Photocatalysis was carried out using several techniques (visible light, ultraviolet radiation and cold plasma), where a plasma jet system produced under normal atmospheric pressure was used in the treatment, with an exposure time of 4 min and an argon gas flow rate of 3 l/min. The hydrophilic properties were studied to apply these compositions in the self-cleaning process and photocatalytic activity. The results show that the ZnSe nanostructures have high wettability under UV light which has been shown to have excellent catalysis in the UV region, making its application as a self-cleaning material an attractive option. [ABSTRACT FROM AUTHOR]

The physical properties of pure and defected ZnSe wurtzite systems were theoretically investigated. From the first-principle study, the wide band gap is 2.7 eV and ZnSe is a non-magnetic direct band-gap semiconductor. The ferromagnetic and antiferromagnetic states are also studied for Fe-doped ZnSe systems. Investigations show that adding iron and the presence of a single Zn vacancy defect leads to the magnetisation of ZnSe. The total energy calculations show that a ferromagnetic state is favourable when Zn is replaced with Fe. The ferromagnetic alignment in the Fe-doped ZnSe wurtzite compound allows it to be in high-spin and half-metallic states. In cases of Zn interstitial and Se vacancy defect in the ZnSe system does not lead to magnetisation. Defect formation energies and Curie temperature of Fe-doped ZnSe systems are estimated from ab-initio calculations. [ABSTRACT FROM AUTHOR]

Magic sized ZnSe nanoclusters have applications in a wide range of areas, such as bioimaging, bio-detection techniques, LEDs and solar cells etc. Despite extensive studies done on ZnSe quantum dots (QDs), the technological potential of photonic behaviour of their lower size range clusters is still largely unexplored. We herein present rapid mustered oil mediated synthesis of magic sized ZnSe with their identification as single-family entities by trapping a fixed position doublet in their absorption spectra. Consistent absorption peaks at 304/305 and 318/19 ​nm irrespective of methods employed are presented. The PL spectra show broad emissions between 350 and 550 ​nm dominating blue region of energy offering scope of further tunability. The mustard oil mediated synthesis was performed using thermal, microwave and ultrasound energy. Despite their size domain of about 2 ​nm, their broad XRD pattern have signature of crystalline nature. Mass spectrometry, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are in good support of ZnSe magic size clusters. Typically, blue region CIE coordinates are estimated from PL emission spectra.

Herein, we report the facile synthesis of ZnSe/HPMC (Hydroxypropyl Methyl Cellulose) nanocomposites by in-situ method. The biodegradable HPMC polymer acts as capping molecule as well as polymer matrix. The optical and structural properties of ZnSe/HPMC nanocomposites were studied by optical absorption, photoluminescence (PL) spectroscopy, FTIR, XRD and TEM measurements. Size of the ZnSe nanoparticles was tuned by controlling the pH of the reaction. As prepared ZnSe nanoparticles were spherical in shape, homogeneously distributed in the polymer and XRD patterns exhibit face centred cubic phase. The present method is a novel approach for the synthesis of ZnSe nanoparticles using HPMC as a capping molecule as well as matrix to develop nanocomposite.

Abstract Colloidal quantum dots (QDs) are attracting research interest because of their unique optical properties that result from the quantum confinement effect. ZnSe QDs, which are II–VI semiconductors, offer a wide direct bandgap (2.7 eV), making them promising for applications such as light-emitting diodes, photodetectors, and biomedical labeling. In the present work, colloidal ZnSe (QDs) were synthesized by the hot-injection method with a Zn:Se ratio of 1:1. The optical properties of ZnSe QDs obtained at different reaction times were investigated by spectrophotometric UV–vis absorption and emission measurements. The as-synthesized ZnSe QDs exhibit blue excitonic emission, and no defect emission was detected. Transmission electron micrographs indicated that the QDs have a spherical morphology with dimensions ranging from 3.69 to 4.53 nm. In particular, the Brus model was applied to demonstrate a correlation between the QD sizes and the optical bandgaps obtained from Tauc plots.

The potential use of large-size ZnSe quantum dots as blue emitters for display applications has greatly inspired the colloidal synthesis. Herein, we report the negative effects of side reactions of large-size ZnSe quantum dots. The side reactions between oleic acid and oleylamine generated amidation products and H2O, which led to the hydrolysis of Zn(OA)2 to Zn(OH)2 and the subsequent formation of zinc oxide (ZnO) and zinc bis[diphenylphosphinate] (Zn(DPPA)2) precipitates. These side reactions resulted in the formation of a defective surface including a Se-rich surface and oxygen-related defects. Such negative effects can be overcome by adopting an etching strategy using potassium fluoride and myristic acid in combination. By overcoating a ZnS shell, blue emissive ZnSe/ZnS quantum dots with a maximum photoluminescence quantum yield of up to 91% were obtained. We further fabricated ZnSe quantum dots-based blue light-emitting diodes with an emission peak at 456 nm. The device showed a turn-on voltage of 2.7 V with a maximum external quantum efficiency of 4.2% and a maximum luminance of 1223 cd·m−2. [ABSTRACT FROM AUTHOR]

A review of the state of research in the development of conductometric gas sensors based on II–VI semiconductors is given. It was shown that II–VI compounds indeed have properties that are necessary for the development of highly efficient gas sensors. In this case, to achieve the required parameters, all approaches developed for metal oxides can be used. At the same time, during a detailed review, it was concluded that sensors based on II–VI compounds have no prospects for appearing on the gas sensor market. The main obstacle is the instability of the surface state, which leads to poor reproducibility of parameters and drift of sensor characteristics during operation. [ABSTRACT FROM AUTHOR]

Colloidal quantum dots (QDs) are attracting research interest because of their unique optical properties that result from the quantum confinement effect. ZnSe QDs, which are II–VI semiconductors, offer a wide direct bandgap (2.7 eV), making them promising for applications such as light-emitting diodes, photodetectors, and biomedical labeling. In the present work, colloidal ZnSe (QDs) were synthesized by the hot-injection method with a Zn:Se ratio of 1:1. The optical properties of ZnSe QDs obtained at different reaction times were investigated by spectrophotometric UV–vis absorption and emission measurements. The as-synthesized ZnSe QDs exhibit blue excitonic emission, and no defect emission was detected. Transmission electron micrographs indicated that the QDs have a spherical morphology with dimensions ranging from 3.69 to 4.53 nm. In particular, the Brus model was applied to demonstrate a correlation between the QD sizes and the optical bandgaps obtained from Tauc plots. [ABSTRACT FROM AUTHOR]

In this work, ZnSe-based polycrystalline ceramics were successfully synthesized from Se and Zn powders in the range of 2.0 GPa and 900 °C–1400 °C by using the high-pressure and high-temperature (HPHT) method. From the acquired experimental results, it was revealed that the fabricated samples were composed of ZnSe with a sphalerite structural type. More specifically, the samples consisted of lamellar and granular grains, and the stomata of the samples showed a trend of first increasing and then decreasing as a function of the elevated temperature. In addition, the infrared transmittance of ZnSe ceramics in the 4 to 18-μm range increased and then decreased by increasing the temperature. When the temperature exceeded the value of 1000 °C, the internal zinc surplus and selenium deficiency of zinc selenide ceramics induced a decrease in the mechanical and optical properties of the ceramics. By optimizing the conditions of the experimental process, the ZnSe synthesized at 1300 °C exhibited better performance with a transmittance of 55%. [ABSTRACT FROM AUTHOR]

The current study explores the prospective of a nitrogen-doped graphene (NG) incorporated into ZnSe-TiO2 composites via hydrothermal method for supercapacitor electrodes. Structural, morphological, and electronic characterizations are conducted using XRD, SEM, Raman, and UV analyses. The electrochemical study is performed and galvanostatic charge-discharge (GCD) and cyclic voltammetry (CV) are evaluated for the supercapacitor electrode material. Results demonstrate improved performance in the ZnSe-NG-TiO2 composite, indicating its potential for advanced supercapacitors with enhanced efficiency, stability, and power density. Specific capacity calculations and galvanic charge-discharge experiments confirmed the promising electrochemical activity of ZnSe-NG-TiO2, which has a specific capacity of 222 C/g. The negative link among specific capacity and current density demonstrated the composite's potential for high energy density and high-power density electrochemical devices. Overall, the study shows that composite materials derived from multiple families can synergistically improve electrode characteristics for advanced energy storage applications. [ABSTRACT FROM AUTHOR]

An ultrathin 15 μm wafer‐based c‐Si solar cell is designed and simulated, wherein the current remedy is done by Cu2SnS3 (CTS) thin film. The ZnSe and AlSb are incorporated as window and back surface field (BSF) layers, respectively, in this model. The ultrathin Si‐based n‐ZnSe/p‐Si exhibits the short‐circuit current density of 30.66 mA cm−2 with an efficiency of 18.80%. The inclusion of p+‐CTS thin film as a second absorber layer has enhanced this current to 42.14 mA cm−2. By absorbing sunlight up to 1200 nm, the CTS layer is able to successfully overcome the constraint of thinner Si wafers on longer‐wavelength photon absorption leading to current augmentation. The addition of p++‐AlSb as the BSF layer also boosts the open‐circuit voltage by 300 mV. The rise in VOC is a result of the larger built‐in potential in ZnSe/Si, Si/CTS, and CTS/AlSb interfaces. With enriched current and voltage, the final proposed n‐ZnSe/p‐Si/p+‐CTS/p++‐AlSb heterostructure theoretically records an efficiency of 35.48% in ultrathin Si solar cells. The current compensation obtained using CTS thin film in this work can give optimism about the future of ultrathin Si solar cells. [ABSTRACT FROM AUTHOR]

Powered by an inexhaustible supply of solar energy, photoelectrochemical (PEC) nitrogen reduction reaction (NRR) provides an ideal solution for the synthesis of green ammonia (NH3). Although great efforts have been made in the past decades, there are still significant challenges in increasing the NH3 yields of the PEC-NRR devices. In addition to the issues of low activity and selectivity similar to electrochemical NRR, the progress of PEC-NRR is also impeded by the limited increase in NH3 yields as the electrode is enlarged. Here, we propose an editable electrode design strategy that parallels unit photo-electrodes to achieve a linear increase in NH3 yields with electrode active area. We demonstrate that the editable electrode design strategy minimizes the electrode charge transfer resistance, allowing more photo-generated carriers to reach the electrode surface and promote the catalytic reaction. We believe that this editable electrode design strategy provides an avenue to achieve sustainable PEC NH3 production. [ABSTRACT FROM AUTHOR]

Nanoparticles of zinc selenide (ZnSe) were produced by an innovative, uncomplicated, and extremely rapid process that took no longer than a few seconds. For the production of zinc ions, zinc chloride was utilized, and selenium was used for the production of selenium ions. The effect of Zn to Se ions ratio on optical properties has been examined. The prepared nanoparticles were tested and characterized by using transmission electron microscope TEM, scanning electron microscope SEM and UV–Visible spectroscopy. The morphological results revealed that the ZnSe has a spherical shape with mean diameter around 15 nm and the band gap of the ZnSe increases with increasing the Zn content in the sample. The prepared materials were tested as antibacterial agent. [ABSTRACT FROM AUTHOR]

Sb2Se3, a promising thin‐film photovoltaic (TFPV) absorber material known for its non‐toxic nature, abundance on Earth, and stability has the inherent limitations of low doping density of 1013 cm−3 and poor carrier mobility of 1.5 cm2 V−1 s−1, leading to a low built‐in potential and inefficient carrier collection. To address these challenges and enhance the built‐in potential and carrier collection, an effective hole‐transport layer (HTL), e.g. CdS, which contains toxic components is used. A less‐toxic alternative is explored: ZnSe as the electron‐transport layer (ETL) to mitigate this issue. In this study, the performance is evaluated of Sb2Se3/ZnSe solar cells using six different HTLs (CuSCN, MoSe2, NiO, Spiro‐OMeTAD, SnS, MoOx) through the utilization of the SCAPS‐1D modeling tool. The HTL plays a critical role in improving the effectiveness of the built‐in potential, enhancing carrier collection, and suppressing back surface recombination. The analysis involves varying the thickness and doping concentration of the absorber, buffer, and HTLs, and exploring the impact of temperature, series and shunt resistance, and the metal work function of the back contact. Among the tested devices, the one with NiO as the HTL demonstrates the highest efficiency, exhibiting a VOC (open‐circuit voltage) of 0.81 V and a PCE (power conversion efficiency) of 24.07%. [ABSTRACT FROM AUTHOR]

Photocatalytic hydrogen production utilizing abundant solar energy to produce high-calorie, clean, and pollution-free hydrogen is an important approach to solving environmental and resource problems. In this work, a high-efficiency flower-like ZnSe/Cu0.08Zn0.92S photocatalyst was constructed through element doping and the formation of a Z-scheme heterojunction. The synergistic effect of Cu doping and the built-in electric field in the heterojunction enhanced light absorption and utilization by the ZnSe/Cu0.08Zn0.92S microflowers, accelerated the separation and transfer of photogenerated electrons and effectively inhibited electron–hole recombination. Thus the photocatalytic hydrogen production ability of the ZnSe/Cu0.08Zn0.92S microflowers was increased significantly. The highly stable ZnSe/Cu0.08Zn0.92S microflowers could provide excellent catalysis of photocatalytic hydrogen production. [ABSTRACT FROM AUTHOR]

The paper presents the results on the development of an optical coating for a single-crystal ZnGeP2 substrate based on a selenide-oxide pair of materials (ZnSe/Al2O3). The obtained coating ensures the operation of OPO in the mid-IR range up to 5 μm wavelengths. The possibility of ZnSe sputtering by the IBS method is shown. The obtained optical coating has a high laser-induced damage threshold (LIDT) value at a 2097 µm wavelength: WoE=3.51 J/cm2 in energy density and WoP= 101 W/cm2 in power density at a 10 KHz pulse repetition frequency and a pulse duration of 35 ns. Thus, it is shown for the first time that the pair of materials ZnSe/Al2O3 can be used for the deposition of optical coatings by the IBS method with high LIDT values for ZnGeP2 optical elements operating in the mid-IR range.

The electronic and magnetic properties of the MnxZn1−xSe system at various impurity atom (Mn) concentrations were investigated using first-principle calculations. The computed values of formation energies were found negative for different manganese concentrations which demonstrate the stability of the investigated systems. For this reason, the ferromagnetic and the antiferromagnetic states are studied for different impurity atom concentrations. The density of states calculations for spin-up and spin-down states show asymmetric which displays the paramagnetic nature of the Mn-doped ZnSe system. The obtained value of the total magnetic moment for different supercells was found 5.0 µB/Mn. A half-metallic state is observed in the presence of Zn vacancy in Mn:ZnSe system. [ABSTRACT FROM AUTHOR]

The physical properties of nanocrystalline systems of cadmium and zinc selenides have been studied experimentally and theoretically. The effect of temperature and various gaseous media on the specific conductivity of films of cadmium and zinc selenides has been experimentally studied. The values of the Fermi energy, the concentration of donor charge carriers in the conduction band, the activation energy of donors, and the temperature coefficient of resistance are theoretically calculated. It is shown that the calculated values correlate with the experimental ones, which will make it possible to predict the stability of the operation of semiconductor devices.

Electrochemical reduction reaction of nitrogen (NRR) offers a promising pathway to produce ammonia (NH3) from renewable energy. However, the development of such process has been hindered by the chemical inertness of N2. It is recently proposed that hydrogen species formed on the surface of electrocatalysts can greatly enhance NRR. However, there is still a lack of atomic-level connection between the hydrogenation behavior of electrocatalysts and their NRR performance. Here, we report an atomistic understanding of the hydrogenation behavior of a highly twinned ZnSe (T-ZnSe) nanorod with a large density of surface atomic steps and the activation of N2 molecules adsorbed on its surface. Our theoretical calculations and in situ infrared spectroscopic characterizations suggest that the atomic steps are essential for the hydrogenation of T-ZnSe, which greatly reduces its work function and efficiently activates adsorbed N2 molecules. Moreover, the liquid-like and free water over T-ZnSe promotes its hydrogenation. As a result, T-ZnSe nanorods exhibit significantly enhanced Faradaic efficiency and NH3 production rate compared with the pristine ZnSe nanorod. This work paves a promising way for engineering electrocatalysts for green and sustainable NH3 production. [ABSTRACT FROM AUTHOR]

The paper presents the results on the development of an optical coating for a single-crystal ZnGeP2 substrate based on a selenide-oxide pair of materials (ZnSe/Al2O3). The obtained coating ensures the operation of OPO in the mid-IR range up to 5 μm wavelengths. The possibility of ZnSe sputtering by the IBS method is shown. The obtained optical coating has a high laser-induced damage threshold (LIDT) value at a 2097 µm wavelength: W o E = 3.51 J/cm2 in energy density and W o P = 101 W/cm2 in power density at a 10 KHz pulse repetition frequency and a pulse duration of 35 ns. Thus, it is shown for the first time that the pair of materials ZnSe/Al2O3 can be used for the deposition of optical coatings by the IBS method with high LIDT values for ZnGeP2 optical elements operating in the mid-IR range. [ABSTRACT FROM AUTHOR]

ZnSe, ZnSe-TiO2 microspheres and nanostructured TiO2 obtained by hydrothermal and sol–gel methods were tested against Staphylococcus aureus ATCC 25923 and Micrococcus lysodeikticus ATCC 4698 before and after lysozyme (Lys) loading. Morphological characterization of inorganic matrices and hybrid organic–inorganic complexes were performed by microscopy techniques (SEM, AFM and Dark Field Hyperspectral Microscopy). Light absorption properties of ZnSe, ZnSe-TiO2 and TiO2 powders were assessed by UV–visible spectroscopy and their ability to generate reactive oxygen species (•OH and O2•−) under visible light irradiation was investigated. Antibacterial activity of ZnSe, ZnSe-TiO2, TiO2, Lys/ZnSe, Lys/ZnSe-TiO2 and Lys/TiO2 samples under exposure to visible light irradiation (λ > 420 nm) was tested against Staphylococcus aureus and Micrococcus lysodeikticus and correlated with ROS photogeneration. [ABSTRACT FROM AUTHOR]

Polycrystalline zinc selenide (ZnSe) and Cr2+ or Fe2+ doped ZnSe are key optical elements in mid-infrared laser systems. The laser-induced damage of the optical elements is the limiting factor for increasing the power and pulse energy of the lasers. In the present work, the optical damage of the ZnSe, Cr2+:ZnSe, and Fe2+:ZnSe samples induced by a repetitively pulsed Ho3+:YAG laser at 2091 nm was studied. The probability of the optical damage and the laser-induced damage threshold (LIDT) were determined for the samples manufactured using different processing techniques. The highest LIDT was found in ZnSe samples annealed in an argon atmosphere. It was also found that the samples annealed in a zinc atmosphere or with hot isostatic pressing resulted in a decrease in the LIDT. The Cr2+-doped ZnSe had the lowest LIDT at 2.1 µm compared to Fe2+-doped or undoped ZnSe. The LIDT fluence of all tested ZnSe samples decreased with the increase in the pulse repetition rate and the exposure duration. The results obtained may be used to improve the treatment procedures of ZnSe, Cr2+:ZnSe, and Fe2+:ZnSe polycrystals to further increase their LIDT.

Herein, ZnSe nanoparticles with good visible-light response were in-situ deposited on the surface of the hollow tubular Co 9 S 8 to form compact Co 9 S 8 /ZnSe heterojunctions via hydrothermal and solvothermal methods. This architecture is beneficial to expose more active sites due to the uniform dispersion of ZnSe particles. Under visible light irradiation, the composites at the optimum Co 9 S 8 amount (5 wt%) take on notably higher hydrogen evolution activity, 967.8 μmol/g/h, which is 3.1 times that of independent ZnSe (314.2 μmol/g/h). A series of tests manifested that the Co 9 S 8 –ZnSe heterojunction significantly promotes the separation of photo-induced electron-hole pairs, notably improves hydrogen evolution kinetics and reduces the electron transfer resistance, which is responsible for the enhanced photocatalytic activity of the composites. Furthermore, the photocatalytic mechanism of the S-scheme heterojunction was proposed based on the measured energy band potentials. This work provides a strategy in constructing inexpensive heterojunction photocatalysts for enhancing the hydrogen evolution performance. As shown in Scheme 1, the Co 9 S 8 /ZnSe heterojunction photocatalysts with ZnSe nanoparticles dispersed on hollow tubular Co 9 S 8 was constructed. Benefiting from the S-scheme heterojunction formed by the built-in electric field, improved hydrogen evolution activity and reduced electron transfer resistance, Co 9 S 8 /ZnSe composites exhibited excellent photocatalytic hydrogen evolution activity. [Display omitted] • The novel hollow tubular Co 9 S 8 /ZnSe heterojunction photocatalysts were constructed. • The addition of hollow tubular Co 9 S 8 reduced the electron transfer resistance. • The optimal Co 9 S 8 /ZnSe composites obtained a H 2 evolution rate of 967.8 μmol/g/h. • The S-scheme heterojunction was proposed to clarify the possible mechanism. [ABSTRACT FROM AUTHOR]

Colloidal quantum dots (CQDs) have emerged as promising candidates for solution‐processed optical gain materials. Despite the substantial progress made with Cd or Pb‐contained CQDs, lasing from the environmentally friendly CQDs remains underexplored. Here, the highly emissive ZnSeTe/ZnSe/ZnS and ZnSe/ZnS CQDs is developed. The optical gain and lasing action from such Te‐alloyed and intrinsic ZnSe/ZnS CQDs across the blue spectral region is achieved. Te‐alloyed ZnSe core manifests a quasitype‐II band alignment with the ZnSe intermediate layer, favorable for suppressing the Auger recombination and also lasing wavelength tuning. The transient absorption spectroscopy reveals evidence of a blue optical gain with a threshold of one exciton per dot and a lifetime of 171 ps in the alloyed CQDs. Under a quasicontinuous‐wave pumping, lasing is observed from the blue CQDs in Fabry–Pérot cavities with a lower threshold fluence of 12.5 µJ cm−2 as compared with the traditional counterparts with heavy metals. The demonstration of heavy‐metal‐free CQD lasing opens up new opportunities in the application of CQDs as efficient and environmental‐friendly gain media. [ABSTRACT FROM AUTHOR]

In-depth understandings of charge carrier transfer dynamics in any artificial catalytic system are of critical importance for the future design of highly efficient photocatalysts. Herein, we synthesized sub-monolayer ZnSe partial-shell coated CdSe/CdS core/shell quantum dots in a controlled fashion. The ZnSe decorated quantum dots were employed as a model catalyst for photogeneration of H2 under light illumination. Both theoretical calculations and experimental results unravel that the growth of ZnSe partial-shell would retard the photogenerated electron transfer, and meanwhile, accelerate the corresponding hole migration process during the H2 photogeneration reaction in the artificial photocatalytic system. As such, the performance of the relevant photocatalytic system can be modulated and optimized, and accordingly, a plausible underlying mechanism is rationalized. [ABSTRACT FROM AUTHOR]

As detection of cancer and diabetes diseases has captured a great attention in the field of biosensing, many ways were introduced to detect these diseases with high accuracy. This paper presents a novel use of zinc selenide (ZnSe) semiconductor material to enhance the sensitivity of a conventional Ag-based surface plasmon resonance biosensor. The proposed sensor structure is simple (BK7 prism/Ag/ZnSe), cost-effective, and easy to design and fabricate. The sensor is tested in the detection of different cancerous cells in human blood, showing an excellent sensitivity of 359 ∘ /RIU. In addiion, it is tested to detect various glucose levels in human urine, and it provides a very high performance with a sensitivity of 366.6 ∘ /RIU, which is 70% better than that of a similar reported work. Thus, the proposed biosensor is capable efficiently to detect various kinds of cancer cells and different glucose concentrations in urine. [ABSTRACT FROM AUTHOR]

This study presents the synthesis of ZnSe nanoparticles (NPs) via precursor solution method; preparation of perovskite and ZnSe:perovskite composites (0, 2, 4, and 6 mg/ml, respectively) via solution processing method. The synthesis of these materials has been confirmed by X-ray diffraction/XRD, UV–Visible spectroscopy, steady-state photoluminescence (PL) spectroscopy, time-resolved photoluminescence (TRPL) spectroscopy, contact angle analysis and scanning electron microscopy/SEM. As-synthesized ZnSe:perovskite composites have been deployed in the fabrication of solar cells. SEM micrographs of these composites have shown a significant reduction in extrinsic defects of perovskite films on incorporation of ZnSe NPs into perovskites matrices indicating improvement in morphology. The contact angle analysis confirmed a significant decrease in the hydrophilicity as contact angle is increased by ~ 10° as compared to that of pristine perovskite. Moreover, TRPL spectroscopy confirmed a modest increase in the lifetimes and hence, reduction in the recombination rate within ZnSe:perovskite composites. Likewise, J-V curve of as-fabricated devices demonstrates an improvement in the performance with the increase in the concentration of ZnSe NPs into perovskite. The best device based on these composites has shown an efficiency of 5.98%, open circuit voltage/Voc of 0.931 V, short circuit current density/JSC of 9.82 mA/cm2 and fill factor/FF of 65.50% which has retained 79.6% of its actual efficiency after 30 days of air exposure. [ABSTRACT FROM AUTHOR]

When the diameter of semiconductor nanowires is below the Bohr radius, confined excitons in the radial direction can freely move along the elongated axis direction, highlighting their potential for applications in quantum information and optoelectronic devices. Controlled anisotropic growth and oriented attachment are viable strategies for producing ultra-long semiconductor nanowires with precisely controlled lengths and diameters. Anisotropic ZnSe nanorods are used as the initial seeds for the controlled anisotropic growth and oriented attachment methods. ZnSe nanorods/nanowires with limiting lengths of tens to hundreds of nanometers are produced. The advantages and limitations of semiconductor nanowires via controlled anisotropic growth and oriented attachment are summarized. The perspective for the promotion of controlled anisotropic growth and oriented attachment is discussed, which allows to promotion of the precise synthesis of semiconductor ultra-long nanowires to develop the fundamental research and applications of ultra-long semiconductor nanowires., (© 2024 Wiley‐VCH GmbH.)

The optical nonlinearity in polycrystalline zinc selenide (ZnSe), excited with 775 nm, 1 kHz femtosecond laser pulses was investigated via the nonlinear transmission with material thickness and the Z scan technique. The measured two photon absorption coefficient β was intensity dependent, inferring that reverse saturated absorption (RSA) is also relevant during high intensity excitation in ZnSe. At low peak intensity I < 5 GW cm–2, we find β = 3.5 cm GW–1 at 775 nm. The spectral properties of the broad blueish two-photon induced fluorescence (460 nm-500 nm) was studied, displaying self-absorption near the band edge while the upper state lifetime was measured to be τe ~ 3.3 ns. Stimulated emission was observed when pumping a 0.5 mm thick polycrystalline ZnSe sample within an optical cavity, confirmed by significant line narrowing from Δλ = 11 nm (cavity blocked) to Δλ = 2.8 nm at peak wavelength λp = 475 nm while the upper state lifetime also decreased. These results suggest that with more optimum pumping conditions and crystal cooling, polycrystalline ZnSe might reach lasing threshold via two-photon pumping at λ = 775 nm.

The parameters of the spin-polarized electronic energy spectrum of ZnSe:T crystals (T = Ti, V, Cr, Mn, Fe, Co, Ni) are studied on the basis of a 2 × 2 × 2 supercell built on the basis of a ZnSe unit cell with a sphalerite structure. The supercell contains 64 atoms, with one Zn atom replaced by one transition 3d element T. The first stage of this study is to calculate in the ideal material ZnTSe parameters of electronic energy bands, dependent on the external hydrostatic pressure. At the second stage, the effect of pressure on the parameters of the electronic energy spectrum in the ZnTSe materials is investigated, taking into account the Zn vacancy. The calculations were performed using the Abinit program. For a better description of strongly correlated 3d electrons of the element T, a hybrid exchange-correlation functional PBE0 with an admixture of the Hartree-Fock exchange potential was used, in which the self-interaction error of these electrons is removed. Based on the obtained spin-polarized electron densities of states, the magnetic moments of the supercells were also determined. A significant effect of pressure on the parameters of electronic energy zones was revealed. So, the ideal ZnTiSe material at zero pressure is a metal for both spin values, but under pressure it becomes a semiconductor. The same material with a point defect, i.e. a vacancy at the site of the Zn atom, exhibits semiconductor properties for both spin orientations at zero pressure. It was found that vacancies radically change the parameters of electronic energy bands. The magnetic moments of the supercell, as integral values of the spin-polarized densities of electronic states, also reflect these changes. Thus, in ZnTiSe material without defects, the magnetic moments of the supercell are 1.92, 2.0 and 2.0, at pressures 0, 21 and 50 GPa, respectively, while in the same material with a vacancy, the corresponding values are 0.39, 0.02 and 0.36. The ideal ZnVSe material at zero pressure is also a metal for both values of the spin moment, but in the presence of a cationic vacancy it is characterized by a pseudogap because the Fermi level is localized in the upper part of the valence band. Ideal ZnFeSe and ZnNiSe crystals are characterized by similar dependences of the electronic energy parameters on the pressure, for both spins. However, the same materials with a cationic vacancy are characterized by the Fermi level immersed in the valence band for a spin up.

This article demonstrates a highly efficient FeS2-based n-ZnSe/p-FeS2/p+-AlxGa1-xSb dual-heterojunction thin film solar cell using SCAPS-1D simulator. The study has been carried out taking the physical parameters from the literature. The influence of thickness, doping, and defect concentration of ZnSe, FeS2, and AlxGa1-xSb layers on the photovoltaic performance of the solar cell has been investigated in details. The power conversion efficiency (PCE) of the n-ZnSe/p-FeS2 single-heterojunction solar cell is ~23.22% with JSC = 47.52 mA/cm2, VOC = 0.59 V, and FF = 82.62%, respectively. The PCE of the solar cell further increases to ~36.75% with JSC = 48.13 mA/cm2, VOC = 0.94 V, and FF = 80.75%, respectively with the insertion of AlxGa1-xSb back surface field (BSF) layer. This increase in PCE is mainly due to the enhancement of VOC which is resulted from the suitable band alignment of the dual-heterojunction devices. These results indicate that FeS2-based dual-heterojunction thin film solar cell with ZnSe and AlxGa1-xSb window and BSF layers, respectively, is a potential candidate to fabricate high efficiency thin film solar cell for harvesting solar energy in the future. [ABSTRACT FROM AUTHOR]

In the present paper, simple hydrothermal and solid-state methods are reported for the synthesis of metal chalcogenide (ZnSe), metal oxide (Co3O4) and their nano-heterostructure (ZnSe/Co3O4 3:1, 1:1 and 1:3 ratios by weight), while their photocatalytic efficiencies are also investigated. The X-ray diffraction results corroborate the good crystallinity and purity of all synthesized products, i.e., ZnSe, Co3O4 and their nanocomposites. The scanning electron micro-images of ZnSe show a mixed morphology of nanoparticles (≈16 nm), including spherical and distorted cubes, while Co3O4 has a worm-like morphology (≈20 × 50 nm). The EDX results show that all the elements are present in accordance with their anticipated amounts in the products. The UV/visible absorption spectrum of ZnSe depicts a sharp absorption at around 480 nm, while Co3O4 demonstrates two prominent peaks, 510 nm and 684 nm. The prepared samples were employed for the photocatalytic degradation of Congo red dye and the nano-heterostructure (ZnSe/Co3O4 3:1) shows an exceptional photocatalytic degradation efficiency of 96%. This enhanced photocatalytic activity was due to the synergic effect of ZnSe and Co3O4 that reduced the electron/hole recombination and caused suitable bandgap alignment. [ABSTRACT FROM AUTHOR]

Some physical properties (structural and electronic) of Zn-based wurtzite structures have been theoretically studied by the density functional theory (DFT). Ab-initio calculations were done using the plane-wave pseudo-potential method within the Atomistix ToolKit (ATK) software package. Detailed investigations on the structural and electronic properties of the binary bulk compounds, ZnO and ZnSe, have been conducted and compared with the obtained studies. Using the modified Becke–Johnson potential has successfully improved the calculated bandgap. From the first-principles calculations for investigated compounds, it is obtained that the valence band maximum and the conduction band minimum, mainly originate from O (Se) p - and Zn s -states. The calculated values of electronic bandgaps of both the compounds are closer to the experimental results, and studied compounds are direct bandgap semiconductors with the transition along with Γ – Γ symmetry. [ABSTRACT FROM AUTHOR]

An unexpected promoting effect of KBr, used as a diluting salt, on the degradation of picric acid (PA) was observed during in situ diffuse reflectance infrared Fourier-transform (DRIFT) spectroscopy experiments performed here under accelerated ageing conditions—at 80 °C and under an inert or oxidative atmosphere. While the formation of potassium picrate was excluded, this promoting effect—which is undesired as it masks the possible effects of test conditions on the ageing process of the material—was assumed to favor a first step of the decomposition mechanism of PA, which involves the inter- or intramolecular transfer of hydrogen to the nitro group, and possibly proceeds up to the formation of an amino group. An alternative diluting salt, ZnSe, which is much less commonly used in infrared spectroscopy than KBr, was then proposed in order to avoid misleading interpretation of the results. ZnSe was found to act as a truly inert diluting salt, preventing the promoting effect of KBr. The much more chemically inert nature (towards PA) of ZnSe compared to KBr was also confirmed, at much higher temperatures than DRIFT experiments, by dynamic differential scanning calorimetry (DSC) runs carried out on pure PA (i.e., PA without salt) and PA/salt (ZnSe or KBr) solid mixtures. [ABSTRACT FROM AUTHOR]

Bulk-heterojunction (BHJ) polymer solar cells have received a great deal of attention mainly due to the possibility of higher power conversion efficiency for photovoltaic applications. Therefore, in this study, relatively novel polymer BHJ solar cells are proposed (ITO/ETL/PTB7:PC70BM/PEDOT:PSS/Au) with various electron transport layers (ETL) such as zinc oxysulfide (Zn(O,S)), zinc selenide (ZnSe), and poly[(9,9-bis(3′-((N,N-dimethyl)-N-ethylammonium)-propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] dibromide (PFN-Br). Here, each ETL material is selected based on the energy bandgap compatibility with ITO as well as the PTB7:PC70BM active layer and is based on other physical properties, which are generally required for efficient photovoltaic responses. Each proposed device is comprehensively optimized and then photovoltaic responses are simulated and compared using the software SCAPS-1D. It was observed that the ITO/Zn(O,S)/PTB7:PC70BM/PEDOT:PSS/Au device offered the highest power-conversion efficiency of up to 17.15% with an open-circuit voltage of 0.85 volts, a short-circuit current of 28.23 mA/cm2, and a fill factor of 70.69%. [ABSTRACT FROM AUTHOR]

Polycrystalline zinc selenide (ZnSe) and Cr2+ or Fe2+ doped ZnSe are key optical elements in mid-infrared laser systems. The laser-induced damage of the optical elements is the limiting factor for increasing the power and pulse energy of the lasers. In the present work, the optical damage of the ZnSe, Cr2+:ZnSe, and Fe2+:ZnSe samples induced by a repetitively pulsed Ho3+:YAG laser at 2091 nm was studied. The probability of the optical damage and the laser-induced damage threshold (LIDT) were determined for the samples manufactured using different processing techniques. The highest LIDT was found in ZnSe samples annealed in an argon atmosphere. It was also found that the samples annealed in a zinc atmosphere or with hot isostatic pressing resulted in a decrease in the LIDT. The Cr2+-doped ZnSe had the lowest LIDT at 2.1 µm compared to Fe2+-doped or undoped ZnSe. The LIDT fluence of all tested ZnSe samples decreased with the increase in the pulse repetition rate and the exposure duration. The results obtained may be used to improve the treatment procedures of ZnSe, Cr2+:ZnSe, and Fe2+:ZnSe polycrystals to further increase their LIDT. [ABSTRACT FROM AUTHOR]

Random quasi-phase matching (RQPM) in polycrystalline materials has been considered as an important technique for nonlinear optical frequency conversion, especially in wideband laser generation involving femtosecond lasers. In this paper, optical rectification (OR) based on RQPM in ZnSe ceramics was investigated for the first time, which could convert ultrashort optical pulses to broadband terahertz waves. A theoretical model of RQPM OR was built, with which the effects of material grain size, thickness, pump wavelength and pump pulse duration on terahertz generation, were simulated and discussed. It was found that RQPM OR in ZnSe is indeed effective in terahertz generation but insensitive to the material grain size and pump wavelength RQPM OR is even better than traditional single crystals such as ZnTe in bandwidth and robustness. The results can be a reference to optimize the RQPM OR nonlinear process, and hopefully, this work will promote the application of costless polycrystalline materials in the hot field of terahertz generation. [ABSTRACT FROM AUTHOR]

ZnSe: x %Er3+ (0 ≤ x ≤ 1.8) thin films were deposited on the glass substrates using a photo-assisted chemical bath deposition method. The X-ray diffraction investigation revealed that the samples exhibited a hexagonal crystalline structure. The undoped ZnSe had a crystallite size of 21 nm, which decreased to 4 nm as the concentration of Er3+ increased. The Scanning electron microscopy images showed that the shape of the particles changed from nanoflakes to glass-like particles after the introduction of Er3+. The expected elemental composition was determined using energy-dispersive spectroscopy. The ultraviolet–visible spectroscopy analysis revealed that increasing the concentration of Er3+ modified the band gap energy within the range of 2.75–4.09 eV. The photoluminescence investigation revealed two distinguishable emission peaks at the energy of 1.79 and 2.34 eV when stimulated with an energy of 5.68 eV. These emission peaks were attributed to the presence of impurities in the host material. The Commission Internationale de l'Eclairage revealed that increasing Er3+ concentration shift the yellow emission from the host towards the light blue region. Incorporating Er³⁺ dopant into the ZnSe lattice significantly alters the structure and optical properties. [Display omitted] • Limited studies have explored the effect of Er3+ ions doped ZnSe on structural and optical properties. • A photo-assisted chemical bath deposition method prepared ZnSe: x %Er3+ (0 ≤ x ≤ 1.8) thin films. • The UV–vis results showed an energy band gap (E g) modification from 2.75 to 4.18 eV by varying Er3+ concentration. • The results revealed exponential luminescence intensity enhancement with increasing Er3+ concentration. • The CIE coordinates show ZnSe: x %Er3+ (0 ≤ x ≤ 1.8) thin films are tunable from yellow to light blue region. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis of ZnSe nanostructures with spherical and flower-like morphology. • Fabrication of ZnSe-based sensors for room temperature NH 3 sensing. • ZnSe with flower-like morphology exhibit superior sensing capabilities. Nanostructured materials, defined by their distinctive physicochemical properties at the nanometer scale, facilitate the innovation of sophisticated applications through their inherent size-dependent phenomena and surface characteristics. In this study, we explore the synthesis of ZnSe nanostructures with distinct spherical and flower-like morphologies by varying the concentration of Ethylenediamine tetraacetic acid (EDTA). Our findings reveal that higher concentrations of EDTA facilitate flower-like morphologies, which provide a large surface area desired for gas sensing applications. Herein, the as-synthesized ZnSe nanostructures were applied for ammonia (NH 3) sensing at room temperature at different concentrations to evaluate their performance. The results obtained indicate that ZnSe nanostructures with flower-like morphology exhibit superior sensing capabilities, demonstrating a good response (ΔR/R air)% of 71 % compared to the 61 % response observed for spherical ZnSe nanostructures for 20 ppm NH 3 gas, measured at room temperature. Additionally, the flower-like ZnSe nanostructures show significantly enhanced response and recovery times, demonstrating their potential as efficient materials for NH 3 detection at room temperature. [ABSTRACT FROM AUTHOR]

Although Z-type heterojunction can significantly improve the catalytic performance of photocatalyst, there have been few reports on Z-type heterojunction about ZnSe. Therefore, it is meaningful to search for the Z-type photocatalyst in ZnSe to enhance its photocatalytic efficiency. ZnIn 2 S 4 , as a novel photocatalyst, its VB (1.72V) and CB (−0.71V) can match with ZnSe, indicating the potential formation of a Z-type heterojunction. Therefore, we hope to construct the ZnIn 2 S 4 /ZnSe photocatalyst by forming Z-type heterojunction to boost the photocatalytic activity of ZnSe. In this paper, ZnIn 2 S 4 /ZnSe heterojunction was prepared through hydrothermal method using ZnIn 2 S 4 , Zn(CH 3 COO) 2 ·2H 2 O and Na 2 SeO 3 as raw materials, and heated at 180 °C for 24 h. The optimum 30 % ZnIn 2 S 4 /ZnSe nanocomposites exhibit superior photocatalytic degradation towards Tc and OTC, with removal rates reaching 80 % and 74 % within 60 min, respectively, significantly higher than the degradation efficiency of pure ZnSe. And in the process of photodegradation for antibiotics, the most significant contribution rate are ∙O 2 − and h+, while ·OH plays a minor role. Herein, we have provided a good example for removing antibiotic residues by using ZnSe based Z-type heterojunction towards environmental remediation. Highly efficient ZnIn 2 S 4 /ZnSe photocatalyst have been constructed by hydrothermal hybridization of ZnIn 2 S 4 and ZnSe towards environmental remediation. [Display omitted] • A highly efficient Z-type photocatalyst ZnIn 2 S 4 /ZnSe was constructed by a facile method. • The catalyst show enhanced photocatalytic degradation for TC and OTC pollutants. • The photo-excited ·O 2 − plays a vital effect under the process of tetracycline degradation catalyzed by ZnIn 2 S 4 /ZnSe. • A good example for overcoming the limitations of pure ZnSe is provided. [ABSTRACT FROM AUTHOR]