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Recently, rising distress over ecological pollution owing to water contamination by coloring effluents primarily due to dyes is of growing concern. The development of semiconductor/magnetic oxide–based nanomaterials has verified to be a potent remediation means for water pollution. In the present article, the fabrication of nanocomposites was carried out by the facile hydrothermal method. The ZnO and ZnSe nanoparticles were in situ formed on the α-Fe2O3 layer, thereby forming a heterojunction. The prepared α-Fe2O3/ZnSe nanocomposite possessed a degradation of 98.9% for a Congo red aqueous solution of 100 ppm. The α-Fe2O3/ZnO nanocomposite showed only 26% degradation of 100 ppm dye solution depicting a poor photocatalytic performance. This is attributed to the formation of recombination-enhanced configuration (type-I heterostructure) in the α-Fe2O3/ZnO nanocomposite (NC). In contrast, α-Fe2O3/ZnSe NC accomplished a higher and enhanced photocatalytic response. The key rationale for elevated photocatalytic response is the establishment of a recombination-free configuration (type-II heterostructure). Thus, α-Fe2O3/ZnSe NC known as one of outstanding nanoparticle-nanocomposite photocatalysts was synthesized under mild conditions exclusive of some multifaceted post-treatment, for dye abatement process. [ABSTRACT FROM AUTHOR]

Zinc Selenide (ZnSe) as an important II-VI semiconductor and one of the first semiconductors discovered with a band gap of around 2.7 eV at 25 °C. ZnSe thin films have been deposited by e-beam evaporation method with different thicknesses from 50 nm to 150 nm and effects of annealing temperature on optical and electrical properties of thin films have been investigated at room temperature (RT), 100°C and 200°C. It has been found that the energy bandgap of semiconductor thin films tend to decrease as the temperature increases. Optical properties of the synthesized films were investigated by UV-VIS spectrometer in the wavelength range of 400-1000 nm. Energy band gap of films were calculated and variation due to variation in the thickness were observed. The least band gap value was found to be 1.92 eV for 150 nm thin at 200°C. The band gap results show the semiconducting nature of films grown. XRD technique was used to study the structural properties and the Hall measurement and I-V characteristics were used to study the electrical properties of the thin films. Hall characteristic of the ZnSe thin films for 150 nm at room temperature show that the material has p-type semiconducting nature which remains same if annealed to 200°C. [ABSTRACT FROM AUTHOR]

In this study, Zinc Telluride (ZnTe)-based solar cells, which are metallic dichalcogenide materials, are used as a solar cell absorbent with the formation appropriate for solar cell use. The data has been analyzed by SCAPS-1D structures software. The replacement of Cadmium Sulfide CdS (buffer) layer by other green and save suitable materials has been investigated. The substituted buffer layers have been ZnSe, ZnS, CdSe, and In2S3. The higher device performance efficiency parameters have been found out when using CdS and ZnSe as buffer layers. SCAPS-1D shows that the optimal p-n junction device eff]iciency parameters have been achieved when the ZnTe (absorber) layer thickness is between 1200-1500 nm, while the ZnSe (buffer) layer thickness is between 20-60 nm, and the thickness of ZnO:Al (window) layer is 25 nm. The results of the simulation provide important hints that may enhance the performance of the cell with empirical studies useful in practical implementation. [ABSTRACT FROM AUTHOR]

The manganese doped zinc selenide nanoparticles (ZnSe:Mn NPs) have been synthesized by thermolysis method using oleic acid and oleylamine as capping agents, and 1-octadecene as solvent. Coating of mesoporous silica is done on ZnSe:Mn (ZnSe:Mn@mSilica) which is further functionalized with amine functional groups by treating with (3-aminopropyl)trimethoxysilane. Further pegylation is done to achieve water dispersibility by conjugating carboxyl groups of poly(ethylene glycol) diacid with the amine groups. These pegylated NPs are subsequently treated with ethylenediamine followed by acrylic acid. Conjugation of tris-(hydroxymethyl-aminomethane) is performed by Michael-type addition reaction to afford ZnSe:Mn@mSilica-PEG-Tris-OH. These tris functionalized NPs have exhibited broad emission ranging from 590-620 nm that is an indicative for their suitability in diagnosis and monitoring progress of cancer treatment. To explore the usefulness of increased surface area because of mesoporosity, doxorubicin is loaded on ZnSe:Mn@mSilica- PEG-Tris-OH NPs through silyl ether linkage and evaluated for cytotoxicity against WEHI-164 mouse fibrosarcoma and RAJI human hematopoietic origin cancer cell lines. A decrease in 12% of cell viability of WEHI-164 cells while 30% decrease in RAJI cell lines (IC50 ≈ 45 nM) are observed. This shows that our formulation has more cytotoxic in RAJI cancer cell lines than that of WEHI-164 cancer cells. These results reveal that the formulation has potential for the application in drug delivery and diagnosis in chemotherapeutics. [ABSTRACT FROM AUTHOR]

The practical application of aqueous zinc ion batteries is still hampered by the side reactions and dendrite growth on Zn anode. Herein, the phase engineering of ZnSe coating layer by incorporating small molecules is developed to enhance the performance of Zn anode. The unique electronic structure of ZnSe⋅0.5N 2 H 4 promises strong adsorption for Zn atoms and enhanced ability to inhibit hydrogen evolution, thereby promoting uniform Zn deposition and preventing by-product and dendrite growth. Meanwhile, fast Zn 2+ transfer and deposition kinetics are also demonstrated by ZnSe⋅0.5N 2 H 4 . As a result, the ZnSe⋅0.5N 2 H 4 @Zn symmetric cell achieves long-term cycling stability up to 1900 h and 300 h at high current densities of 5 mA cm -2 and 20 mA cm -2 , respectively. The assembled ZnSe⋅0.5N 2 H 4 @Zn||NH 4 V 4 O 10 full cell presents outstanding cycling stability and rate capability. This work highlights the key role of crystal phase control of protective layer for high-performance zinc anode., (© 2024 Wiley-VCH GmbH.)

The utilization of photoelectrochemical cells (PEC) for converting solar energy into fuels (e.g., hydrogen) is a promising method for sustainable energy generation. We demonstrate a strategy to enhance the performance of PEC devices by integrating surface-functionalized zinc selenide (ZnSe) semiconductor nanocrystals (NCs) into porous polymeric carbon nitride (CN) matrices to form a uniformly distributed blend of NCs within the CN layer via electrophoretic deposition (EPD). The achieved type II heterojunction at the CN/NC interface exhibits intimate contact between the NCs and the CN backbone since it does not contain insulating binders. This configuration promotes efficient charge separation and suppresses carrier recombination. The reported CN/NC composite structure serves as a photoanode, demonstrating a photocurrent density of 160 ± 8 μA cm -2 at 1.23 V vs a reversible hydrogen electrode (RHE), 75% higher compared with a CN-based photoelectrode, for approximately 12 h. Spectral and photoelectrochemical analyses reveal extended photoresponse, reduced charge recombination, and successful charge transfer at the formed heterojunction; these properties result in enhanced PEC oxygen production activity with a Faradaic efficiency of 87%. The methodology allows the integration of high-quality colloidal NCs within porous CN-based photoelectrodes and provides numerous knobs for tuning the functionality of the composite systems, thus showing promise for achieving enhanced solar fuel production using PEC.

Co-doped Zinc selenide (ZnSe) is a promising material because of a high photoluminescence efficiency and wide spectral range emission in the visible region. In this work, ZnSe and Eu3+/Yb3+ co-doped ZnSe crystals were grown by the chemical vapour transport method. Photoluminescence and optical measurements revealed the effect of trivalent rare earth Eu3+/Yb3+ ions on the emission of new lines with enhancement intensity. In the photoluminescence spectrum, some sharp and intense lines were observed that allow for the possibility of covering a broad emission range. Moreover, the optical measurement showed a lower bandgap compared to that of pure ZnSe bulk crystal. This material is suitable for developing optoelectronic devices, which can emit light in the visible and near infrared range with an improved emission efficiency and wide tunability.

Use of inorganic charge transport layer has demonstrated relatively stable perovskite solar cells (PSCs). NiOx is the most widely used inorganic hole transport layer in inverted PSCs and different techniques and doping in this layer have been reported to improve the performance of these devices. This manuscript describes the synthesis of NiOx thin film which act as hole transport layer on glass substrate at the initial stage and PSC devices were fabricated at the secondary stage. Effect of post deposition annealing temperature on the composition, tuning of the work function and aligning it with perovskite work function increase the hole transport efficiency and improve the open circuit voltage of devices from 0.96 to 1.08 V is reported. Ultraviolet photoelectron spectroscopy results were used to check the change in work function and X-ray photoelectron spectroscopy to probe the underlying reason for improvement of devices are also included. The charge transfer efficiency is checked by the results of time resolved photoluminescence spectra is also given. Devices with NiOx as hole transport layer and ZnSe as electron transport layer are also described and performance of devices is also included in this manuscript. [ABSTRACT FROM AUTHOR]

Chalcogenide nanostructures are the materials with diverse applications. Here, we report rapid hydrothermal synthesis of crystalline ZnSe quantum dots (QDs), avoiding the use of toxic chemicals. To the best of our knowledge, this is the first report on very rapid (5 h) hydrothermal synthesis of pristine ZnSe QDs. Elemental selenium is used as a source for selenium. Structural, morphological, compositional, and optical properties of the semiconductor were studied. Structural properties (X-ray diffraction) demonstrate that the particles have grown in a single cubic phase. Morphological studies show formation of agglomerated QDs (4 nm). The material possess stoichiometric ratio of the constituent elements that are uniformly distributed. Selected area electron diffraction (SAED) study indicated the material is polycrystalline in nature. Optical properties demonstrated that the QDs are suitable for optoelectronic devices exhibiting room temperature photoluminescence. Commission Internationale de l'Éclairage (CIE) chromaticity diagram shows the material exhibits violet emission and hence suitable for violet LEDs that have potential ability in clinical applications. [ABSTRACT FROM AUTHOR]

Hybrid hierarchical micro/nanostructures possess great potential in engineering of advanced electrode materials for sodium‐ion batteries (SIBs). Herein, a sandwich hierarchical architecture composed of ZnSe nanoparticles fastened in N‐doped carbon polyhedra anchoring onto graphene with the modification of MoSe2 nanosheets (ZnSe⊂N‐C@MoSe2/rGO) is synthesized by a self‐template and subsequent selenization strategy. Due to the distinctive architectural and multicompositional features, these hybrids deliver a high reversible capacity of 319.4 mAh g−1 at 1 A g−1 for 1800 cycles, 206.5 mA h g−1 at 6 A g−1 for 2800 cycles, and 177.7 mAh g−1 at 10 A g−1 for 5000 cycles, as well as a better rate capability up to 10 A g−1 with a reversible capacity of 224.4 mAh g−1 as an anode material for SIBs. By comparing the capacity contribution, electrochemical impedance spectra and DNa+ of different materials, the advantages of ZnSe⊂N‐C@MoSe2/rGO are confirmed. The sodium storage mechanism of hybrids is further revealed by in situ X‐ray diffraction patterns and high‐resolution transmission electron microscopy results. The improved sodium storage properties of hybrids manifest the significance of elaborate construction of novel multicomponent hierarchical architectures with higher complexity. [ABSTRACT FROM AUTHOR]

The infrared (IR) is a strategically important band for numerous applications from environment to biochemical imaging. Here a novel IR optical component integrates more than 2000 plano-concave microlenses on the zinc selenide (ZnSe) surface within a footprint of $5\times 5$ mm2 is proposed by a combined method of femtosecond laser direct irradiation and chemical wet etching. Microlenses with diameter from 15 to $30~\mu \text{m}$ are realized by controlling the laser power and etching time. The uniform close-packed microlens arrays (MLAs) with minimized volume and high transparency at wavelengths of $0.76\sim 22\mu \text{m}$ are realized. The MLAs have relatively good topography and surface quality. The modulation transfer function (MTF), imaging test and optical-focusing test confirm the outstanding IR imaging. Owing to the merits of micro-size, light weight, high integration and excellent IR imaging performance, the as-fabricated MLA is promising in cutting-edge mid-IR and far-IR application, such as IR sensing system, imaging system, and so on. [ABSTRACT FROM AUTHOR]

Measurements of mass attenuation coefficients and X‐ray absorption fine structure (XAFS) of zinc selenide (ZnSe) are reported to accuracies typically better than 0.13%. The high accuracy of the results presented here is due to our successful implementation of the X‐ray extended range technique, a relatively new methodology, which can be set up on most synchrotron X‐ray beamlines. 561 attenuation coefficients were recorded in the energy range 6.8–15 keV with measurements concentrated at the zinc and selenium pre‐edge, near‐edge and fine‐structure absorption edge regions. This accuracy yielded detailed nanostructural analysis of room‐temperature ZnSe with full uncertainty propagation. Bond lengths, accurate to 0.003 Å to 0.009 Å, or 0.1% to 0.3%, are plausible and physical. Small variation from a crystalline structure suggests local dynamic motion beyond that of a standard crystal lattice, noting that XAFS is sensitive to dynamic correlated motion. The results obtained in this work are the most accurate to date with comparisons with theoretically determined values of the attenuation showing discrepancies from literature theory of up to 4%, motivating further investigation into the origin of such discrepancies. [ABSTRACT FROM AUTHOR]

A Cu 2 ZnSnSe 4 (CZTSe) photovoltaic absorber thin films were prepared using a 2-step selenization process on a Ti substrate including a Na precursor layer and a Na-free Ti substrate, and the effect of Na on the solar cell performance was compared. A CZTSe flexible solar cell fabricated on a Ti foil substrate exhibited an efficiency of 3.06%, which was less than half that of a solar cell fabricated on a soda lime glass substrate. This was attributed to the absence of Na and severe Zn crowding near the back contact. By depositing a 100‐nm-thick sodalime glass thin film on a Ti substrate to supply Na, the efficiency increased up to 5.59%. In the Na-doped CZTSe absorber layer grown on the Ti substrate, the back crowding of Zn was eliminated and the upper part of the absorption layer was converted to a Zn-rich environment, which prevented the formation of Cu Zn antisite defects. Image 1 • Cu 2 ZnSnSe 4 solar cells on a flexible Ti foil using a two step process. • By supplying Na using soda-lime thin film, the efficiency of 5.59% was obtained. • Na has a great influence on the local distribution of Cu and Zn and hole concentration. • Depending on the presence of Na, the Cu diffusion and the MoSe 2 thickness varied. [ABSTRACT FROM AUTHOR]

The temperature dependence of the reduced activation energy w = ε/kBT of the conductivity σ has been utilised for determining the impurity conduction mechanism in doped semiconductors in many studies. Herein, the formula for deconvoluting w when plural conduction mechanisms appear is used to confirm the analysis of the data of the Hall-effect measurements on Al-doped n-ZnSe samples. The analysis is performed on the basis of an impurity-Hubbard-band model which includes ε2 conduction in the top Hubbard band as well as ε3 and Efros-Shklovskii (ES) variable-range hopping (VRH) conduction processes in the bottom Hubbard band. As the result of the analysis, transitions among the three hopping conduction mechanisms of ε2, ε3, and ES VRH are clearly shown in the temperature dependence of w as well as in that of the Hall mobility, which are hardly noticed in the temperature dependence of σ. In addition, the power-law exponent of the prefactor of ES VRH conductivity is determined through the fit to the temperature dependence of w to show that it decreases from ∼ 1.5 to ∼ 0 with increasing net donor concentration. [ABSTRACT FROM AUTHOR]

We have developed high-gain and highly sensitive ZnSe-based organic–inorganic hybrid ultraviolet avalanche photodiodes (UV-APDs). The inorganic ZnSe-based wafers (i-ZnSSe active layer/n-ZnSSe) were grown by molecular beam epitaxy (MBE) on n-type GaAs substrates. The inorganic UV-transparent conducting polymer window layers of poly 3,4-ethylenedioxythiophene:poly-styrenesulfonate (PEDOT:PSS) were formed by spin-coating and a photolithography technique instead of the inkjet printing technique, which we previously reported. We have obtained a thin uniform window layer with a mesa-shaped edge by an optimized photolithography process. The leakage current before the breakdown voltage was suppressed to < 10−10 A/mm2, which is lower than that of the APD device fabricated by inkjet printing. The maximum external quantum efficiency was improved to ηmax = 70% (λ = 340 nm) using the photolithography technique compared with the inkjet printing (ηmax = 50%). The maximum responsivity was improved from 3 A/W to 10 A/W. The maximum multiplication factor was improved from M = 90 to M = 3100. [ABSTRACT FROM AUTHOR]

Metal oxide photocatalysts have the disadvantages of large band gap and high internal resistance, and their photoelectrochemical properties are restricted. Metal selenides are generally characterized by narrow bandgap width, low internal resistance, high utilization rate of sunlight and superior photoelectrochemical performance. The ZnSe/MoSe 2 heterostructure composite was successfully constructed by loading ZnSe nanoparticles onto MoSe 2 nanoplates with three-dimensional flower-like structure. In this heterostructure composite, ZnSe nanoparticles are uniformly encapsulated by MoSe 2 nanoplates, and the larger contact surface facilitates the transfer of carriers between heterojunction, while the three-dimensional flower structure of MoSe 2 can transport and collect photogenerated carriers. This heterojunction composite has a full-band absorption capability of UV and visible light. Photocatalytic tests showed that the photocatalytic activity of the heterojunction photocatalyst was more than twice of MoSe 2 and more than 4 times of ZnSe at the optimum ZnSe composite ratio, and photoelectric performance of that was 2.75 times of MoSe 2. The results show that the photoelectrochemical performance of ZnSe/MoSe 2 has been greatly improved, mainly because of the 0D/2D structure and band matching of ZnSe/MoSe 2 , so that the photogenerated electrons excited on the ZnSe conduction band can be transported to the conduction band of MoSe 2 , thereby improving the carriers' separation efficiency and photoelectrochemical performance. [ABSTRACT FROM AUTHOR]

The erosion issue of ZnO nanorod arrays (NRAs) film is the major obstacle in surface sensitization of ZnO NRAs grown on Zn foil substrate for photoelectrochemical (PEC) applications. In this paper, PEC performance of ZnO NRAs grown on Zn foil substrate was greatly enhanced by coating ZnSe and CdSe on the surface of ZnO NRAs. Dense ZnO NRAs were in - situ grown on seed-free Zn foil substrate in a NH 3 ·H 2 O and NaOH hydrothermal system. ZnSe/CdSe co-sensitized ZnO heterostructures were then successfully synthesized using ZnO NRAs as precursors by two successive in - situ ion exchanges without damaging Zn foil and ZnO NRAs film. To obtain optimal photoconversion efficiency, anion exchange time and temperature were optimized. ZnO/ZnSe/CdSe heterostructures with optimized structure were shown as a layer of compact ZnSe/CdSe nanofilm conformally and uniformly coated on ZnO NRAs, which leads to efficient separation of photogenerated carriers, significant enhancement in visible-light absorption, and excellent PEC performance with photocurrent density of 3.008 mA/cm2 (−0.2 V vs. Ag/AgCl) and photoconversion efficiency of 1.99% (0.418 V vs. RHE in polysulfide electrolyte solution), 27.55 and 40.61 times higher than those of ZnO NRAs, respectively. Image 1 • ZnO/ZnSe/CdSe NRAs on flexible Zn foil were first prepared by in - situ ion exchanges. • Instead of nanodots, conformal and uniform ZnSe/CdSe nanofilm was coated on ZnO NRAs. • ZnO/ZnSe/CdSe NRAs on Zn foil obtain excellent photoconversion efficiency of 1.99%. [ABSTRACT FROM AUTHOR]

In the photoelectrochemistry reaction, the electrode is most important. As a common electrode material, the metal oxide has a large band gap and high internal resistance, which is disadvantageous for photocatalytic hydrogen production. Metal selenide generally has a narrow band gap and low internal resistance, which is a promising new type of photocatalyst. A FeSe 2 /ZnSe heterojunction photocatalyst is constructed by loading ZnSe nanoparticles on FeSe 2 nanorods. In this heterostructure, ZnSe is uniformly supported on the surface of FeSe 2 to form a 0D/1D structure. Experiments have confirmed that the photoelectrochemical activity and photocatalytic H 2 production rate of this heterojunction photocatalyst is greatly improved, and its optimum performance is three times of ZnSe in photoelectrochemical activity and 2.3 times in photocatalytic H 2 production rate. Further analysis reveals that the internal resistance of the composite photocatalyst is greatly reduced due to the compositing of FeSe 2 , and the carrier separation efficiency is also improved. In this FeSe 2 /ZnSe heterojunction, the conduction band of ZnSe is more negative than that of FeSe 2 , and the photogenerated electrons generated on the conduction band of ZnSe can be transferred to that of FeSe 2 , thereby prolonging the carrier lifetime and improving photoelectrochemical activity. This work confirms that FeSe 2 /ZnSe is a very effective heterostructure, which avoids the addition of precious metals and rare earth metals and shows great application prospects. FeSe 2 nanorods were composited with ZnSe nanoparticles to construct 1D/0D heterostructure which exhibits as much as 2 times enhancement on photoelectrochemical activity. Image 1 • FeSe 2 nanorod/ZnSe heterostructure photocatalysts were obtained. • The photoelectrochemical activity of the heterostructure photocatalysts is largely enhanced. • There is a carriers transform between the FeSe 2 nanorod/ZnSe heterostructure. [ABSTRACT FROM AUTHOR]

In this work, we report the effect of sandwiching of Au nanosheets on the structural and electrical properties of ZnSe thin films. The ZnSe films which are grown by the thermal evaporation technique onto glass and yttrium thin film substrates exhibit lattice deformation accompanied with lattice constant extension, grain size reduction and increased defect density upon Au nanosandwiching. The temperature dependent direct current conductivity analysis has shown that the 70 nm thick Au layers successfully increased the electrical conductivity by three orders of magnitude without causing degeneracy. On the other hand, the alternating current conductivity studies in the frequency domain of 10 MHz to 1800 MHz have shown that the alternating current conduction in ZnSe is dominated by both of quantum mechanical tunneling and correlated barrier hopping of electrons over the energy barriers formed at the grain boundaries. The Au nanosheets are observed to increase the density of localized states near Fermi level and reduce the average hopping energy by ~5 times. The conductivity, capacitance, impedance and reflection coefficient spectral analyses have shown that the nanosandwiching of Au between two layers of ZnSe makes the zinc selenide more appropriate for electronic applications and for applications which need microwave cavities. [ABSTRACT FROM AUTHOR]

This work studies extinction properties of ZnSe quantum dots terminated with either Se-surface or Zn-surface (Se-ZnSe or Zn-ZnSe QDs). In addition to commonly observed photoluminescence quenching by anionic surface sites, Se-ZnSe QDs are found to show drastic signatures of Se-surface states in their UV-visible (Vis) absorption spectra. Similar to most QDs reported in literature, monodisperse Zn-ZnSe QDs show sharp absorption features and blue-shifted yet steep absorption edge respect to the bulk bandgap. However, for monodisperse Se-ZnSe QDs, all absorption features are smeared and a low-energy tail is identified to extend to an energy window below the bulk ZnSe bandgap. Along increasing their size, a cyclic growth of ZnSe QDs switches their surface from Zn-terminated to Se-terminated ones, which confirms that the specific absorption signatures are reproducibly repeated between those of two types of the QDs. Though the extinction coefficients per unit of Se-ZnSe QDs are always larger than those of Zn-ZnSe QDs with the same size, both of them approach the same bulk limit. In addition to contribution of the lattice, extinction coefficients per nanocrystal of Zn-ZnSe QDs show an exponential term against their sizes, which is expected for quantum-confinement enhancement of electron-hole wavefunction overlapping. For Se-ZnSe QDs, there is the third term identified for their extinction coefficients per nanocrystal, which is proportional to the square of size of the QDs and consistent with surface contribution. [ABSTRACT FROM AUTHOR]

The bi-structured ZS active material with high graphitisation, high specific surface and abundant mesopores has been successfully synthesised by simple room temperature solvents. The material has high performance in lithium-ion batteries. [Display omitted] • Dual construction of zinc selenide by CN network framework and P-π conjugation. • The preparation method is simple, without precious metal additives, and the raw materials are abundant. • Alloy compounds with low carbon content for high cycle stability. • The underlying reasons for the high and improved performance of lithium-ion batteries are explained and characterized. High-capacity lithium anode materials are very important for the development of lithium storage. However, the volume expansion and electron transport during charging and discharging hinder the development of high capacity and longevity. Herein, the three-dimensional P-π conjugate and nitrogen-doped carbon (CN) network framework was synchronously constructed by a simple and practical double construction strategy to solve the problems of volume expansion and electron transport. The experimental results indicate that the successfully synthesized transition metal zinc selenide (ZnSe) composites material possesses excellent electrochemical properties: an initial reversible capacity is capacity of 1211.8 mAh/g, and the reversible discharge capacity remains at 936.4 mAh/g after 300 cycles (at 1 A/g current density). It is much better than that of pure ZnSe. The enhanced electrochemical performances of the anode can be attributed to its high surface area and abundant mesopores constracted by the 3D CN network framework. Furthermore, the P-π conjugation reduces the system energy and thus accelerates the electron transport. These characteristics provide numerous pathways and sites for Li+ transfer and storage, thus contributing to the pseudo-capacitance capacity. The present work may provide new ideas and strategies for the solution of electrode material expansion and electron transport problems. [ABSTRACT FROM AUTHOR]

It is known that a material’s volume and the surface structuring by the nanoparticles causes a significant change in the material’s basic properties. In this aspect, the structuration of the surface of semiconductors is of interest, because their wide potential application in optoelectronics can extend the products’ transparency, hardness, wettability, and other important parameters. This paper presents possible methods for the surface modification of zinc selenide and zinc sulfide when carbon nanotubes are deposited on the surface by the application of the laser-oriented technique. It also shows changes of the spectral, mechanical, and wetting characteristics of the considered materials. Using the molecular dynamic simulations, the possible process of the carbon nanotubes penetration into the considered surfaces is presented. The simulation results are partially supported by the obtained experimental data.

Cadmium telluride (CdTe), a metallic dichalcogenide material, was utilized as an absorber layer for thin film–based solar cells with appropriate configurations and the SCAPS–1D structures program was used to evaluate the results. In both known and developing thin film photovoltaic systems, a CdS thin–film buffer layer is frequently employed as a traditional n–type heterojunction partner. In this study, numerical simulation was used to determine a suitable non–toxic material for the buffer layer that can be used instead of CdS, among various types of buffer layers (ZnSe, ZnO, ZnS and In2S3) and carrier concentrations for the absorber layer (NA) and buffer layer (ND) were varied to determine the optimal simulation parameters. Carrier concentrations (NA from 2 × 1012 cm−3 to 2 × 1017 cm−3 and ND from 1 × 1016 cm−3 to 1 × 1022 cm−3) differed. The results showed that the use of CdS as a buffer–layer–based CdTe absorber layer for solar cell had the highest efficiency (%) of 17.43%. Furthermore, high conversion efficiencies of 17.42% and 16.27% were for the ZnSe and ZnO-based buffer layers, respectively. As a result, ZnO and ZnSe are potential candidates for replacing the CdS buffer layer in thin–film solar cells. Here, the absorber (CdTe) and buffer (ZnSe) layers were chosen to improve the efficiency by finding the optimal density of the carrier concentration (acceptor and donor). The simulation findings above provide helpful recommendations for fabricating high–efficiency metal oxide–based solar cells in the lab.

ZnSe nitrogen-doped carbon composite nanofibers (ZnSe@N-CNFs) were derived as anode materials from selenization of electrospinning nanofibers. Electron microscopy shows that ZnSe nanoparticles are distributed in electrospinning nanofibers after selenization. Electrochemistry tests were carried out and the results show the one-dimensional carbon composite nanofibers reveal a great structural stability and electrochemistry performance by the enhanced synergistic effect with ZnSe. Even at a current density of 2 A g−1, the as-prepared electrodes can still reach up to 701.7 mA h g−1 after 600 cycles in lithium-ion batteries and 368.9 mA h g−1 after 200 cycles in sodium-ion batteries, respectively. ZnSe@N-CNFs with long cycle life and high capacity at high current density implies its promising future for the next generation application of energy storage.

The CuGaTe 2 thermoelectric material has garnered widespread attention as an inexpensive and nontoxic material for mid-temperature thermoelectric applications. However, its development has been hindered by its low intrinsic carrier concentration and high thermal conductivity. This study investigates the band structure and thermoelectric properties of (CuGaTe 2 ) 1- x (ZnSe) x ( x = 0, 0.25%, 0.5%, 1%, 1.5%, and 2%). The research revealed that the incorporation of Zn and Se atoms enhanced the level of band degeneracy and electron density of states near Fermi level, significantly raising carrier concentration through the formation of Zn Ga - point defects. Simultaneously, when the doping content reached 1.5%, the ZnTe second phase emerged, collaborating with point defects and high-density dislocations, effectively scattering phonons and substantially reducing lattice thermal conductivity. Therefore, introducing ZnSe can simultaneously optimize the material's electrical and thermal transport properties. The (CuGaTe 2 ) 0.985 (ZnSe) 0.015 sample reaches peak ZT of 1.32 at 823 K, representing a 159% increase compared to pure CuGaTe 2 .

Zinc selenide (ZnSe) was analyzed using x-ray photoelectron spectroscopy (XPS). A small notched rod was fractured in the XPS vacuum system at 6 × 10−4 Pa to create an oxygen-free surface for analysis. Spectral regions for Zn 2p, Zn 3d, Zn LMM, O 1s, C 1s, Se 3d, Se 3p, and Se LMM and valence band regions were acquired. The presence of carbon could not be confirmed due to interferences between C 1s and Se LMM and between C KLL and Zn 3s. It is believed that any carbon present is very low. [ABSTRACT FROM AUTHOR]

• Toxic-free Mn-doped ZnSe quantum dots were synthesized and control by zinc precursors. • ZnSe quantum dots were doped with Mn2+ ions through the nucleation doping process. • 4T 1 to 6A 1 transition by Mn2+ allows the narrow emission region of the violet-blue of ZnSe to extend to the orange region. • Correlation between structure and optical properties of doped quantum dots was investigated. We have successfully demonstrated the colloidal hot-injection process to easily obtain the Mn-doped ZnSe quantum dots (QDs) with a size of about 4–5 nm, and d -spacing is 0.31 nm, corresponding to the (1 1 1) lattice plane of ZnSe. Experimental results show that UV–vis absorption and fluorescence spectra were recorded to elucidate the role of Mn2+ ions substituted into ZnSe, which resulted in the carrier transfer of luminescent sites by a small amount of Mn2+ dopant. The small size of the Mn-doped ZnSe QDs offers intriguing opportunities for their application in photonic, bioimaging, and spintronics devices. [ABSTRACT FROM AUTHOR]

ZnSe powders have been prepared by vapor reaction during combustion synthesis. The powders contain both cubic and hexagonal ZnSe, where the fraction of the hexagonal phase increases with increasing distance from the evaporation source. The powders consist of spherical particles and rod-like crystals with sizes from submicron to a few microns. In UV–Vis region, the ZnSe powders have two absorption edges at 450–500 nm and 650–700 nm, likely connected with intrinsic band-gap transition and defect energy levels. From the optical absorption data, the band-gap of the ZnSe powders is estimated to be 2.4–2.5 eV. Under an UV or blue excitation, the ZnSe powders show very weak near-band-edge emission but strong defect-induced red emission. It appears that the ZnSe powders synthesized by vapor reaction clearly differ from the bulk ZnSe sample by melt solidification in both phase composition and optical properties. [ABSTRACT FROM AUTHOR]

Antireflection microstructured surface were fabricated on ZnSe through a rapid and scalable method which was called femtosecond laser direct writing (FsLDW). With this technology, micrometer level inverted pyramid and cone arrays were fabricated precisely. The measured transmittance were about 11.3% higher compared with the plain ZnSe at 9µm in the ideal situation. These results were in good accord with the simulations which were calculated by geometric and diffractive field tracing techniques. [ABSTRACT FROM AUTHOR]

Polycrystalline zinc selenide is doped with an iron impurity to a concentration of ~1019 cm−3 in a zinc vapor atmosphere by the thermal diffusion method, and the distribution profile of optically active iron Fe2+ is obtained. The effect of the Fe2+ concentration on impurity-and defect-related ZnSe luminescence spectra at low temperatures is determined. In the range of 1.28—1.31 eV, a luminescence line with a decay time of ~0.341 ms is detected, with its intensity increasing in regions with Fe2+ concentration close to the maximum one. The line is attributed to the luminescence center arising due to the Fe2+ interaction with a background impurity or defect in ZnSe. [ABSTRACT FROM AUTHOR]

Herein, we report synthesis of silica-coated ZnSe nanoparticles (SZNPs), by varying the mass to volume ratio of ZnSe : TEOS i.e. mass to mass ratio of ZnSe : SiO2 ranging from 0.0267 to 0.1071. These SZNPs showed enhanced photodegradation of methylene blue (MB) solution under visible light. Silica coating on ZnSe NPs reduces the toxicity concerns for its wide use as photocatalyst. XRD of bare ZnSe NPs confirms hexagonal crystal structure, and TEM depicts size range of SZNPs around 7 nm. FTIR and Raman measurements confirm the presence of different chemical and silanol groups attached to bare ZnSe and SZNPs. Optical absorption and photoluminescence (PL) show a red shift due to silica coating on ZnSe NPs compared to bare ZnSe. This is due to silanization of ZnSe, as silica shell reduces the recombination of photon-generated electron and hole pairs. Photocatalytic experiments on methylene blue (MB) by bare and SZNPs have been conducted, optimal SZNPs i.e. 0.0535 sample (mass ratio of ZnSe:SiO2) exhibits enhanced photo-generated free radicals. An increase in photodegradation of SZNPs, i.e. from 35 to 46% has been observed compared to bare counterparts (ZnSe). Stability decreased by only 7% after 4th cycle of reuse, depicting efficacy of the SZNPs photocatalyst in the degradation of MB. A pseudo-first-order reaction kinetics has been observed for photodegradation of MB with highest rate constant of 8.6 × 10-3 min-1 for SZNPs (1.0000:0.0535) sample. [ABSTRACT FROM AUTHOR]

Abstract Polycrystalline ZnX (X = S, Se) and CdTe thin films were prepared by rf magnetron sputtering and by thermal vacuum evaporation (CdTe films), respectively. The structural properties were studied by X-ray diffraction (XRD), which revealed that ZnX films are polycrystalline with a marked (111) texture. After irradiation with protons crystallite sizes decreased while mechanical strains increased. Thicknesses of ZnX films and surface roughness have been measured by X-ray reflectometry (XRR) with thickness values between 58 nm and up to 163 nm and with surface roughness between 1.7 nm and 2.4 nm. Morphological investigations were made by scanning electron microscopy (SEM), drops - free surfaces with compact and uniform aspect being deposited. Absorption and transmission measurements were carried out for all samples deposited on optical glass substrates. Experimentally determined bandgap energies were between 2.31–2.75 eV for ZnSe layers, respectively, 3.10–3.65 eV for ZnS films. Optical transmissions in VIS-NIR regions are higher than 60% for both ZnSe and ZnS films. Glass/ITO/ZnS/ZnSe/CdTe/Cu:Au structures in superstrate configuration were produced by depositing CdTe absorber layers by thermal vacuum evaporation (TVE). Action spectra of the external quantum energy (EQE) and the current-voltage (I-V) characteristics in AM 1.5 conditions (the density power of the incident light is equal with 100 mW/cm2) corresponding for double-heterojunction ZnS/ZnSe/CdTe photovoltaic structures were investigated before and after irradiations with high energy protons (3 MeV). Graphical abstract Unlabelled Image Highlights • Fabricated polycrystalline ZnX (X = S, Se) films show a marked (111) texture. • Optical band gap values increase with the increase in film thickness for all ZnX (X = S, Se) films. • Optical band gap values of ZnX (X = S, Se) films decrease after protons irradiation. • The photovoltaic performances of ITO/ZnS/ZnSe/CdTe/Cu:Au structures were affected after protons irradiation. [ABSTRACT FROM AUTHOR]

In this work, the heavy aluminum doping effects on the compositional, structural, optical, dielectric and electrical properties of ZnSe thin films are investigated. It is observed that the Zn/Se compositional ratio increases with increasing Al content. The major cubic phase of ZnSe becomes more pronounced compared to the hexagonal phase. In addition, the presence of Al in the structure of ZnSe causes lattice constant contraction, decreased the grain size and increased both of the strain and defect density. Optically, the Al doping increased the light absorbability and widens both of the energy band gap and energy interbands which are present in the band gap of ZnSe films. Moreover, the Al doping into ZnSe lowers the high frequency dielectric constant and enhances the optical conductivity. On the other hand, the capacitance spectra which are studied in the frequency domain of 0.01–1.80 GHz displayed negative capacitance effect associated with resonance–antiresonance phenomena upon doping of ZnSe with Al. Such enhancements in the physical properties of ZnSe that are achieved via Al doping make the zinc selenide thin films more appropriate for electronic and optoelectronic technological applications. [ABSTRACT FROM AUTHOR]

We study features of point emitters in ZnSe-based quantum wells using laser-based spectroscopy with a high spatial resolution. We determine the experimental conditions under which quantum emitters formed by donor-acceptor pairs are observed. We discuss the possibility of studying individual defects forming a donor–acceptor pair using the spectrum of the corresponding quantum emitters. [ABSTRACT FROM AUTHOR]

Abstract Sodium-ion batteries (SIBs) are considered as a promising candidate to lithium-ion batteries (LIBs) owing to the inexpensive and abundant sodium reserves. However, the application of anode materials for SIBs still confront rapid capacity fading and undesirable rate capability. Here we simultaneously grow ultrafine ZnSe nanoparticles on the inner walls and the outer surface of hollow carbon nanospheres (ZnSe@HCNs), giving a unique hierarchical hybrid nanostructure that can sustain a capacity of 361.9 mAh g−1 at 1 A g−1 over 1000 cycles and 266.5 mAh g−1 at 20 A g−1. Our investigations indicate that the sodium storage mechanism of ZnSe@HCNs electrodes is a mixture of alloying and conversion reactions, where ZnSe converts to Na 2 Se and NaZn 13 through a series of intermediate compounds. Also, a full cell is constructed from our designed ZnSe@HCNs anode and Na 3 V 2 (PO 4) 3 cathode. It delivers a reversible discharge capacity of about 313.1 mAh g−1 after 100 cycles at 0.5 A g−1 with high Columbic efficiency over 98.2%. The outstanding sodium storage of as-prepared ZnSe@HCNs is attributed to the confinement of ZnSe structural changes both inside/outside of hollow nanospheres during the sodiation/desodiation processes. Our work offers a promising design to enable high-power-density electrodes for the various battery systems. Graphical abstract A hierarchical hybrid nanocomposite of ultrafine ZnSe nanoparticles growing on/in amorphous hollow carbon nanospheres (ZnSe@HCNs) has been prepared via simple solution reflux and post-calcination in Ar/H 2. The ZnSe nanoparticles grow on both sides of HCNs, thus preventing severe aggregation and stabilizing structures of electrodes upon cycling. When used as a promising anode for SIBs, the hybrid composites could manifest excellent electrochemical performance with high reversible capacity, long-term cyclic stability and excellent rate capability. Image 1 Highlights • ZnSe nanoparticles grow on both the inner walls and the outer surface of hollow carbon nanospheres (ZnSe@HCNs). • The sodium storage mechanism of ZnSe@HCNs electrodes is a mixture of alloying and conversion reactions. • A full cell constructed from the ZnSe@HCNs anode and Na 3 V 2 (PO 4) 3 cathode was demonstrated. • ZnSe@HCNs exhibit long-cycle and high-rate sodium storage. • The robust structure can accommodate the large volume and structural changes. [ABSTRACT FROM AUTHOR]

Abstract Rare earth elements possessing unique 4f electrons have been investigated as excellent candidates for luminescent centers in doped II-VI nanocrystals, because of their abundant emission colors based on the 4–4f or 5d-4f transitions. In particular, ZnSe quantum dot (QDs) fabricated with the lanthanide Europium (Eu) can emit in both the visible and near-infrared region. In our work, the structural, morphological and optical properties were investigated the color-tunable ZnSe:Eu QDs. We focused on the ZnSe:Eu QDs synthesized by controlling Eu amount. According to the results, the optical property of ZnSe:Eu QDs showed that emission in the bluish to yellow-ocher range, and concentration quenching occurred upon increasing the Eu amount. The expected structure of the ZnSe:Eu QDs with Eu (Eu/Zn = 0.5, 1 and 1.5) was verified by XRD, TEM, XPS and gibbs free energy value using a HSC chemistry software. Highlights • The color-tunable ZnSe:Eu quantum dots (QDs) prepared in situ for the first time. • The ZnSe:Eu QDs showed ZnSe and Eu2+ and Eu3+ emission depending on Eu amount due to the concentration quenching. • The ZnSe:Eu QDs with Eu/Zn=1.5 perhaps contains more oxygen Eu 3 O 4 , Eu 2 O 3 and EuO on the surface of Eu3+-doped ZnSe QDs. [ABSTRACT FROM AUTHOR]

Abstract Radial 1-D nano-heterojunctions have distinct optoelectronic properties. However, their complex fabrication process is still the bottleneck of device applications. Herein, a facile atomic layer deposition (ALD) method was used to coat a polycrystalline CdS thin film with high uniformity and controllable thickness on the surface of the as-synthesized p-type ZnSe nanowires, for fabricating radial 1-D ZnSe-CdS nano-heterojunctions. The nano-heterojunctions exhibited excellent optoelectronic properties. Under blue/violet light, the nano-heterojunctions obtained a response radio of ∼5 × 103, a responsitivity of ∼1.43 A/W, a gain of ∼3.78 and a detectivity of ∼0.57 × 1012 cmHz1/2W−1 at zero bias. Furthermore, the nano-heterojunction also showed obvious photovoltaic characteristic with a power conversion efficiency of ∼0.96%. This method is expected to play an important role in nano-heterojunction construction and their device applications. Graphical abstract Image 1 Highlights • Radial 1-D ZnSe-CdS nano-heterojunctions were fabricated by ALD method. • Self-powered photodetector was constructed and exhibited high performance. • The nano-heterojunction showed obvious photovoltaic characteristic. [ABSTRACT FROM AUTHOR]

In this article, we report the effects of insertion of yttrium, gold and yttrium-gold (YAu) metallic nano-slabs on the structural, optical and dielectric properties of ZnSe thin films. The ZnSe thin films which are prepared by the thermal evaporation technique under vacuum pressure of 10-5 mbar exhibit hexagonal structure. While the insertion of the 70 nm thick Y layers does not alter the lattice parameters and stress values, the Au and YAu layers increased the lattice parameters along the a- and c-axes and decreased the stress values. In addition, the insertion of these metallic layers slightly alters the value of the energy band gap and increases the width of the interbands. The light absorbability are increased by 1.4, 2.0 and 2.4 times upon insertion of Y, Au and YAu, slabs, respectively. On the other hand, the dielectric and optical conductivity analyses has shown that the use of the YAu stacked metal layers increases the real part of the dielectric constant, the optical conductivity, the drift mobility and extended the plasmon frequency range from 35.1 to 254.0 (Ωcm)-1, from 1098 to 1766 cm2/Vs and from 0.94-3.11 GHz to 2.13-4.83 GHz, respectively. The insertion of the two stacked metallic layers between two layers of ZnSe makes the ZnSe more appropriated for thin film transistor technology. [ABSTRACT FROM AUTHOR]

Abstract On the basis of spin density functional calculation, the electronic and magnetic properties of ZnSe doped with double impurities Zn 1-2x Fe x Co x Se (x = 0.05) are studied using the Korringa-Kohn-Rostoker coherent potential approximation (KKR-CPA) method within the local density approximation (LDA). The half-metallic ferromagnetic nature of (Fe, Co) doped ZnSe is investigated. Therefore the electronic structure and magnetic properties of Zn 1-2x Fe x Co x Se exhibit a half-metallic ferromagnetic character; the stability of ferromagnetic (FM) compared to the disorder local moment (DLM) has been discussed. Our calculation is supported by Monte Carlo simulations (MCS) based on the heat bath algorithm. We have examined the effects of system size L on magnetization, specific heat and magnetic susceptibility. The spin density functional calculation results are in good agreement with the literature, especially for 5% of (Co, Fe) each, which gives the most interesting results. Highlights • The magnetic properties of ZnSe doped with double impurities has been investigated. • The half-metallic ferromagnetic nature appears in doped ZnSe with (Fe, Co). • The effect of size lattice ZnSe is studied. • Monte Carlo simulation is used. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Fundamentals of scintillation in inorganic scintillators. • Properties of common inorganic scintillators and discussion of investigations on ZnSe based scintillators. • Factors affecting scintillation performance of ZnSe based scintillators. • Basics of quantum dots, efforts taken for synthesis of ZnSe quantum dots and advantages of ZnSe quantum dot scintillators. Abstract Modern scintillator detectors act as an efficient tool for detection and measurement of ionizing radiations. ZnSe based materials have been found to be a promising candidate for scintillation applications. These scintillators show much-needed scintillation efficiency along with advantages such as high thermal and radiation stability, less-toxicity, non-hygroscopicity, emissions in the visible range and small decay time etc. Further, in quantum confinement regime, they show improvement in luminescent properties and size dependent emissions. In this review article, the attempt has been made to trace the progress of ZnSe based materials towards highly efficient quantum dot scintillators. Here, the fundamental process of scintillation has been explained. Factors such as doping, annealing, heavy ion irradiation which affects the scintillation response of ZnSe based scintillators have also been discussed. Method of synthesis plays a key role in optimization of quantum dot properties. Hence, it has been tried to trace the development in methods of synthesis of quantum dots. With optimized synthesis, we can extend applications of these highly efficient quantum dot scintillators for various scientific and industrial applications. [ABSTRACT FROM AUTHOR]

A rapid and single-step method for the fabrication of a zinc selenide (ZnSe) concave microlens array through the high-speed line-scanning of a femtosecond laser pulse is presented. Approximately 1.1 million microlenses, with minimized volume and high transparency at wavelengths between approximately 0.76–20 μm were fabricated within 36 min. More importantly, the size of the microlenses can be controlled by adjusting the laser power. Their high-quality infrared optical performance was also demonstrated. This method holds great promise for the development of ZnSe-based micro-optical devices.

• A green and simple synthesis of ZnSe/ZnS quantum dots in aqueous solution was presented. • The influences of synthesis parameters on structure and optical properties of the particles were investigated in details. • ZnSe/ZnS showed better luminous intensity and lifespan than ZnSe and blue luminous. The core-shell quantum dots of ZnSe-ZnS were synthesized in aqueous solution using glutathione (GSH) in an environmentally friendly way. The effects of the concentration of GSH, the synthesis temperature and the NaOH concentration (pH) on the microstructural and optical properties of the prepared core-shell systematically were investigated. Analysis of the XRD patterns and TEM particle images confirmed that the round-typed ZnSe-ZnS quantum dots of size 3 to 5 nm were formed. Comparing to the single core ZnSe, the core-shell ZnSe-ZnS showed an increase in photoluminescence (PL) emission intensity up to 130%. In addition, the core-shell quantum dots showed a good long-term stability maintaining their high PL intensity for at least 84 days. The synthesis process optimization was discussed in detail. The light emission intensities of the quantum dots were dependent on the GSH concentration. The optimum GSH concentration for the core-shell synthesis was found to be around 0.1 mmol. High temperature above 70 C for the core-shell synthesis generally improved the optical properties. However, light discharge characteristics were correlated with the core-shell synthesis temperature and the pH in solution. At the high temperatures of 70 °C and 90 °C, the emission intensities were degraded with high pH of 13 due to the dissociation of the ligand were accelerated. The optimized ZnSe-ZnS quantum dots showed high color purity emitting blue fluorescence light of 378 nm with the narrow full width at half maximum (FWHM) less than 20 nm. Optimization of synthesis parameters showed the possibilities of the simple and eco-friendly manufacture of long term stable and efficient ZnSe-ZnS core-shell quantum dots in aqueous solutions for display applications. [ABSTRACT FROM AUTHOR]