Zinc Precursor Research Articles

Green synthesis of ZnO nanoparticles by pineapple peel extract from various alkali sources

ABSTRACT Zinc oxide nanoparticles (ZnO NPs) are concerned as potential materials due to their wide-ranging applications. The green synthesis of ZnO NPs using of plant extract as capping agent has been attracted much of interest of reserachers. Pineapple peel wastes are aboundance in Thailand and its extract contained high levels of phytochemical compounds (flavonoids and their derivatives). In this study, pineapple extract was used as a capping agent in ZnO NP synthesis, and KOH and a lye solution were used as reducing agents for comparison. The XRD patterns exhibit pure-phase ZnO with high crystallinity. The averages of the most petite crystalline sizes obtained from the Scherrer equation calculation of the prepared ZnO powder are 64.61 and 65.41 nm for KOH solution and lye use, respectively. Fourier transform infrared (FTIR) spectroscopy confirmed the presence of ZnO particles and pineapple extract residue in the as-received powder. Scanning electron microscope (SEM) images and transmission electron microscope (TEM) images showed the nano-size of the synthesized particles. The flower-like ZnO-NPs from a 0.06 M zinc precursor and KOH solution exhibited fascinating optical properties. Finally, all the results showed that lye from wood ash could be applied in ZnO nanoparticle synthesis using pineapple peel extract.

Bimetallic oxide nanoparticles contained hollow spheres with sodium as a core: a promising energy storage advanced structure

The bimetallic oxide nanoparticles as outer shell with sodium entrapped as a core part of a hollow porous core–shell (HoPoCs) can be a promising battery electrode composition. Till now, scientists are struggling to synthesize ternary metal oxide hollow spheres due to the reactions between diverse cations and anions of different metal precursors. Also, the extremely reactive character of sodium prevents it from remaining alone without compound formation is unveiled. Here for the first time, we entrapped sodium and synthesized bimetallic nanoparticles contained outer shell hollowsphere (Na@ZnO@MoO2) successfully by sorption (absorption + adsorption) of two metal precursors (sodium molybdate dihydrate and zinc chloride) in two steps without adding any reaction inhibiting agent. As a result, significantly Na is entrapped as a core and ZnO and MoO2 nanoparticles forming the outer shell of the sphere. ‘Na’ entrapment is confirmed by X-ray photoelectron spectroscopy and high-angle annular dark-field scanning transmission electron microscopy elemental mapping. We employed our sodium entrapped HoPoCs bimetallic oxide nanoparticles sphere (Na@ZnO@MoO2) as a battery anode getting advantages from their structural specialty shows excellent battery properties promising for application in energy storage technologies. The initial specific capacity of these HoPoCs-Na@ZnO@MoO2 sphere is 940 mAh/g (1C), with exceptional stability (790 mAh/g) after 1000 cycles at a current density of 2C) and excellent rate capability. This approach will motivate the synthesis of other superior reactive element entrapped core–shell metal oxides for next-generation rechargeable batteries and other advanced suitable applications like microreactor, protector of explosive materials, and so on.

Inkjet-printed blue InP/ZnS/ZnS quantum dot light-emitting diodes

Inkjet-printed quantum dot light-emitting diodes (QLEDs) are considered to be ideal candidates for use in full-color displays. However, preparation of eco-friendly blue InP QLEDs using inkjet printing techniques remains rather challenging due to the inferior optical properties of QDs. Here, we present the first efficient method for generating inkjet-printed QLEDs with high color purity using blue InP/ZnS/ZnS QDs as the emitting layer. A two-step heat-up and thick shell strategy was employed for the preparation of blue InP/ZnS/ZnS QDs with a photoluminescence (PL) peak at 465 nm, full width at half-maximum of 38 nm, and PL quantum yield (QY) of ∼ 96 %, which are the records for blue InP QDs. We found that the use of a zinc iodide precursor and anhydrous oxygen reaction environment is critical to determining InP core size, and the size distribution of InP cores can be improved by separating formation of InP magic size clusters and cores via a heat-up step at low temperature. We used two kind of zinc precursors to facilitate shell growth, and the engineered shell thickness suppresses energy transfer, enabling InP/ZnS/ZnS QDs film with high PLQYs and contributing to efficient inkjet printing of QLEDs. These results can facilitate the development of blue InP QLEDs for large-area electroluminescent full-color displays.

Impact of sperm protamine on semen quality and fertility

Protamines are the nuclear proteins essential for chromatin compaction during spermatogenesis. During chromatin compaction, histones are replaced by transition proteins, which are then replaced by protamines. This process is essential for DNA stability. Protamines are rapidly evolved proteins with high evolutionary variation and encompass positively charged amino acids, especially 48% of arginine. Cysteines present in their sequence allow the formation of disulfide bonds between adjacent protamine molecules. Protamine 1 (PRM1), Protamine 2 (PRM2), and Protamine 3 (PRM3) are reported in mammals. Among these, PRM1 and PRM2 were extensively studied. The normal PRM1 and PRM2 ratios in men, stallions, and mice are 1:1, 3:1, and 1:2, respectively. However, in infertile males, the PRM1: PRM2 ratio is altered due to decreased PRM2 expression, which, in turn, is due to incomplete PRM2 precursor processing and zinc deficiency. In bull, ram, and buck, PRM2 mRNA is present but not PRM2 protein. In mice, rats, bulls, and men, the protamine cluster contains an open reading frame called protamine 3 (gene-4 or protamine-3). The proportion of protamine deficient sperm in the sample is indicative of problems in protamination. Recently, omics technologies, RT-qPCR, and gene knockout-based studies also reported the presence of protamine in sperm. All these semen quality and knockout studies envisage that protamines are indispensable for fertility. Henceforth, protamine-like biomolecules also may be evaluated for fertility prediction or markers in addition to the existing structural and functional attributes of sperm.

Green synthesis of zinc sulfide-reduced graphene oxide composite and its application in sodium-ion batteries

A green chemistry synthesis of a sodium-ion battery (SIB) anode is described. The anode comprises nanometric Sphalerite (ZnS) film, coated uniformly on reduced graphene oxide. Compliance of an energy storage component with sustainability goals requires the following attributes: i) exclusive use of abundant and non-toxic raw materials; ii) energy-minimized processing that uses cheap materials of construction, and involves a minimal waste generation, and no hazardous wastes, and iii) high energy efficiency without compromising power performance. Only low-cost, abundant raw materials are used in this synthesis: zinc acetate, 1 wt% hydrogen peroxide solution, and in-situ generated hydrogen sulfide. The synthesis protocol is based on hydrogen peroxide sol-gel (HPSG) processing, i.e. synthesis of zinc peroxide sol followed by a delicate pH change to deposit the zinc peroxide on dispersed graphene oxide. HPSG is a wet-chemistry process that does not rely on energy-rich hydrothermal/solvothermal steps, water or solvent evaporation, or the use of dispersing organic solvents, and the zinc precursor is fully converted to ZnS. We show film deposition from as low as 1 wt% aqueous hydrogen peroxide solution. The anode exhibits excellent electrochemical characteristics: 550 mAh g −1 at 0.1 A g −1 after 150 cycles between 0 and 2.5 V vs. Na reference, and a high-rate capability of 420 mAh g −1 at 2 A g −1 (ca 5 C rate). Despite being a conversion type anode, ZnS exhibits similar voltage hysteresis (and energy efficiency) to tin sulfide - graphene-oxide composite, a conversion-alloying anode. Despite being a SIB anode, it compares favorably with the Fe 3 O 4 and MnO LIB conversion anodes, commended for their high energy efficiency. SYNOPSIS: A green chemistry synthesis of a sodium ion battery anode based on ZnS-rGO. • A green chemistry synthesis of a sodium ion battery anode based on ZnS-rGO. • ZnS-rGO anode revealed a high specific capacitance of 543 mAh g −1 . • Anodes show lower voltage hysteresis, higher 1st cycle discharging–charging efficiency.

Controllable preparation and photocatalytic activity of hierarchical flower-like microspheres clustered by ZnO porous nanosheets

• 3D hierarchical flower-like microspheres clustered by ZnO porous nanosheets were prepared. • The average pore size can be controlled by the calcination temperature. • The CV degradation rate of the optimum sample is high up to 77.6%. • The high photocatalytic activity originates from the high separation efficiency of photogenerated electrons and holes proved by the photocurrent, impedance and fluorescence emission decay. The zinc carbonate hydroxide hydrate was prepared by the hydrolysis reaction between zinc nitrate and urea at 90 °C for 12 h. Then, the hierarchical flower-like microspheres clustered by ZnO porous nanosheets are obtained by calcination of precursor zinc carbonate hydroxide hydrate without structure deformation. The ZnO porous nanosheets were characterized by XRD, TEM, SEM, BET, UV–Vis absorption, photocurrent, impedance and fluorescence emission decay. The average pore size can be controlled from 11.77 to 49.53 nm with the calcination temperature increased from 300 to 500 °C. The ZnO porous nanosheets show well photocatalytic activity for degradation of crystal violet. Besides, the ZnO porous nanosheets calcined at 400 °C exhibit the highest photodegradation rate, due to the highest separation efficiency of photogenerated charge carriers with the highest photocurrent, the lowest migration resistance and the longest fluorescence emission decay lifetime.

Facile preparation of nanostructured ZnO via low-temperature hydrothermal method upon changing the precursor anion: The study of structural, morphological, and optical properties

The synthesis of ZnO nanostructures was carried out via a low-temperature hydrothermal route; using three different zinc precursors: ZnSO4, ZnCl2, and Zn(ac)2. X-ray diffraction analysis confirmed that all synthesized samples have high purity wurtzite hexagonal structure. The calculation of lattice parameters indicated that the precursor’s anion and the hydrothermal time strongly affected the lattice parameters. The SO42- anion capped the polar surface growth, which leads to 2D nanostructures. However, the Cl- anion boosted growth along the c axis and inhibited the lateral axes, which lead to 1D nanostructures. The microstrain and crystallite size of the samples were determined using the Williamson-Hall (W-H), Size-Strain Plot, and Halder-Wagner (H-W) methods. The SEM images indicated morphological differences in the formation of the synthesized samples, confirming that the anion of the precursor and the hydrothermal time play a determining role in the shape of the ZnO nanostructures. All the ZnO samples show strong absorption in the ultraviolet region with an onset of absorbance in the range 250–335 nm; blue shifting was observed for all samples indicating a large bandgap, such as Eg(Cl-) > Eg(SO42-) > Eg(C2H3O2-) and the Urbach energy that reflects the disorder was calculated, such thatEu(ZA6) > Eu(ZS6) > Eu(ZC6). There was a correlation between optical and structural proprieties: the bandgap decreased with increasing microstrain, however, Urbach energy increased.

Mechanically induced atom transfer radical polymerization with high efficiency via piezoelectric heterostructures

A facile ultrasonication induced atom transfer radical polymerization (ATRP) mediated via piezoelectric heterostructure was developed. ZnO/BaTiO 3 heterostructure was prepared by in-situ deposition of zinc precursor on BaTiO 3 particles followed by high temperature annealing. Under ultrasonic activation, as-synthesized piezoelectric ZnO/BaTiO 3 heterostructure with an elevated macroscopic polarization could facilitate piezoelectric induced electron-hole pairs with more efficient separation and transfer, leading to the enhanced piezocatalytic in controlled living polymerization. High efficiency of ultrasonication mediated ATRP of methyl methacrylate (MMA) by ZnO/BaTiO 3 heterostructure about 63.1% conversion was achieved under 4 h ultrasonic agitation, providing PMMA homopolymer with well-defined molecular weight, narrow molecular dispersity and high end-group fidelity. Furthermore, implications of CuBr 2 /TPMA concentrations, piezoelectric materials, ZnO/BaTiO 3 heterostructure loading and distinct monomer were systematically investigated. Process of ultrasonication-mediated ATRP could be readily controlled by ultrasound switch on/off. The versatility of ultrasonication-mediated ATRP system was further verified by the preparation of star-like polymer. The ability of transfer piezoelectric-induced electrons from ZnO/BaTiO 3 heterostructure to CuBr 2 /TPMA and nature of ZnO/BaTiO 3 heterostructure were investigated to reveal the mechanism of ultrasonication mediated ATRP. A facile and robust atom transfer radical polymerization catalyzed by piezocatalyst with high efficiency was developed in this study. • Piezoelectric catalyst enabled mechanically induced atom transfer radical polymerization with high efficiency.

Impact of structural defects on the photocatalytic properties of ZnO

ZnO photocatalytic materials have been prepared using three precursors (Zinc Acetate, Zinc Hydroxide, and Zinc Peroxide), and the effect of calcination temperature on structural and photocatalytic properties of ZnO has been investigated. XRD, UV–Vis, BET, XPS, Time-Resolved Microwave Conductivity (TRMC), Raman, and Electron Paramagnetic Resonance (EPR) have been used to correlate the impact of the surface area, the introduction of oxygen and/or zinc vacancies, and the charge carrier dynamics, with their photocatalytic properties. The main objective is to provide a new approach to the impact of structural defects on ZnO semiconductors determined by using Raman and EPR techniques, and by coupling with the important role of the surface area considered as one of the most relevant characteristics in photocatalysis in terms of performance. The fewer surface defects, the more photoactive the catalyst is. The results are discussed for the model degradation of formic acid and phenol under UV-irradiation.

Effect of Zn/Sn Ratio on Perovskite Solar Cell Performance Applying Off-Stoichiometric Cu2ZnSnS4/Carbon Hole-Collecting Electrodes.

Low-cost inorganic hole-transporting materials (HTMs) accompanied by a printable carbon electrode is an efficient approach to address the limitation of material cost of perovskite solar cells (PSCs) and get this technology closer to commercialization. The present work is focused on optimizing the Zn/Sn ratio of Cu2ZnSnS4/carbon hole collectors in n-i-p structured PSCs, where CuInS2/carbon is applied as the reference hole collector. This composition regulation is a solution to address the challenge of composition-related defects of the Cu2ZnSnS4 (CZTS) material. The Zn/Sn ratio was tuned by the initial proportion of the zinc precursor during the nanoparticle (NP) synthesis using a heating-up procedure. It was found that the enhancement of the Zn/Sn ratio leads to a gradual increase of the optical band gap. More importantly, an increased density of B-type defect clusters [2ZnCu + ZnSn] is confirmed using Raman results. Additionally, results from the cyclic voltammetry measurement show that by increasing the Zn/Sn value, the highest occupied molecular orbital (HOMO) of HTM is pulled down. These data match the upward trend of photovoltage. CZTS HTM with an optimal Zn/Sn ratio of 1.5 has a compatible energy level, along with the features of uniform and smooth coverage. The best efficiency of about 14.86% was obtained for optimal CZTS/carbon-based PSCs, which reaches from 14.86 to 15.49% after 25 days of aging.

Field emission characteristics of ZnO nanowires grown by catalyst-assisted MOCVD on free-standing inorganic nanomembranes

ZnO field emitters on freely suspended inorganic nanomembranes (NMs) were synthesized by catalyst-assisted metal organic chemical vapor deposition (MOCVD) using the precursors zinc acetylacetonate hydrate and oxygen. The morphology and the possibly involved growth mechanisms of the randomly distributed ZnO nanostructures were investigated by scanning electron microscopy and by energy-dispersive x-ray spectroscopy. The findings indicate a growth process that involves the vapor–liquid–solid as well as the vapor–solid–solid mechanism. The field emission (FE) properties of such ZnO nanowire (NW) samples showed to be highly reproducible and independent of the investigated Si-based substrate types. Herein, a new type of flexible substrate for the MOCVD process has been introduced that allows for the direct growth of ZnO NWs on free-standing membranes for potential FE-based sensor applications. A turn-on field of 4.1 V µm−1 was detected for a macroscopic emission current density of 10 µA cm−2 and the stability test revealed fluctuations of only 9% around the mean emission current over a duration of 3 h proving a reliable and stable operation of such devices. Moreover, approaches were identified to further enhance the FE characteristics of the ZnO NWs by variation of the synthesis parameters and by enlargement of the NM area.

The finished polyester fabric with hot NH4OH pretreatment and mixed ZnO-Zn(OH)2 nanoparticles for hydrophobic property

This work aims to modify the hydrophobic coated polyester fabrics using 2%w/v ammonium hydroxide (NH4OH) at 90℃ prior and subsequently dipped in two difference aqueous zinc solution batchs containing 0.6%w/v zinc precursors with/without starch and NH4OH, finally dehydration, and characterized by the attenuated total reflection - Fourier transform Infrared (ATR-FTIR) and Raman spectroscopy (Raman), X-ray diffraction (XRD), Field emission scanning electron microscope (FE-SEM), Energy dipersive spectrometry (EDX), and Water contact angle (WCA) of 10 mL dropping at 23℃ and humidity of 63%. Raman spectra and XRD patterns results showed e-zinc hydroxide (e-Zn(OH)2), zinc oxide nanoparticle (ZnO NP) and ZnO-starch nanocomposite crystallized in the orthorhombic and hexagonol wurzite structure, respectively. The increasing intensities of Raman vibrational modes at 369 cm-1 and 750 cm-1 confirmed the increased of e-Zn(OH)2 content with additional starch, therefore, WCA trend of those finished fabric surfaces decreased. WCA optimum of 138° before washing and 136° after 5 washing cycles of the treated fabric which was activated by NH4OH acts as scourer and also as promoter of e-Zn(OH)2/ZnO NPs as revealed from ATR-FTIR result. While, other observed lower hydrophobic property after 5 washing cycles due to the hydroplilic ZnO-starch nanocomposite.e-Zn(OH)2/ZnO NPs. While others, there were observed lower hydrophobic property after 5 washing cycles due to the hydroplilic ZnO-starch nanocomposite.

Optical Properties of ZnS Quantum Dots: Applications in Solar cells and Biomedicine

Optoelectronics and optical filter applications require wide bandgap semiconductors as photo-anode and surface passivation layers in sensitized solar cells and biomedical and biosensors fields such as optical filters [1–4]. Selecting suitable wide bandgap semiconductors increases the valuable implementation of desired devices. However, bulk semiconductors harvest only a particular spectrum, QDs help in harvesting large radiation spectra because of the tunable bandgap. Also, aqueous-based methods are eco-friendly, economical, biocompatible, and non-toxic. Therefore, in this study, ZnS quantum dots (QDs) were synthesized at 9.5 pH and 70 ͦ C temperature using an aqueous-based chemical route method. A comparative study was presented using hydrazine hydrate and ammonium chloride as reducing agents for Zinc precursor and 3-mercaptopropionic acid (MPA) as capping agents. Confinement was achieved in ZnS using MPA as a stabilizer. Optical properties were studied using a photoluminescence (PL) spectrophotometer where photoluminescence (PL) shows emission behavior and photoluminescence excitation (PLE) shows excitation behavior of ZnS. Emission peaks were observed at 386 nm in as-prepared ZnS NPs and at 316 nm in confined QDs. Sharp band edge luminescence and the possibility to confine ZnS NPs show its eligibility in optoelectronics and optical filters in biological applications.

Fabrication of orderly changed ZnO hierarchical structures by calcining different zinc precursors and morphology-depended photocatalytic property

Different zinc precursors, Zn 5 (OH) 6 (CO 3 ) 2 (S1), the mixture of Zn 5 (OH) 6 (CO 3 ) 2 and ZnCO 3 (S2), and ZnCO 3 (S3) can be formed by simple hydrothermal method using different amount of reagents, and then these different zinc precursors were calcined to produce orderly changed morphologies of hierarchical ZnO: nanosheets, nanospheres and/or microrods. The addition of NH 4 F inhibits the formation of OH – , and increases the concentration of CO 3 2– , which leads to the presence of zinc precursor of ZnCO 3 and the formation of novel microrod-based ZnO after calcination. To our best knowledge that when HMT or CO(NH 2 ) 2 was added to the reaction solution, the presence of the precursor of ZnCO 3 and/or the microd-based ZnO was not reported under these solution environment. Comparing to S1 and S2, the H 2 evolution rate of the microd-based S3 is significantly enhanced, which value is 223.43 μmol*g −1 after 4h. The orderly changed morphologies lead to the transformation of active planes from (0 0 2) to (1 0 0) and the improvement of electron excitation ability, which may be favourable for the improvement of photocatalytic H 2 evolution. Different zinc precursors, Zn 5 (OH) 6 (CO 3 ) 2 (S1), the mixture of Zn 5 (OH) 6 (CO 3 ) 2 and ZnCO 3 (S2), and ZnCO 3 (S3) were formed by simple hydrothermal method using different amount of reagents, and then these zinc precursors were calcined to produce various hierarchical morphologies of ZnO: nanosheets, nanospheres and/or microrods in an orderly way. In other words, different zinc precursors correspond to various morphologies. The addition of NH 4 F inhibits the formation of OH – , and increases the concentration of CO 3 2– , which leads to the presence of zinc precursor of ZnCO 3 and novel microrod-based ZnO structure after calcination. Comparing to S1 and S2, the H 2 evolution rate of the microd-based S3 is significantly enhanced, which value is 223.43 μmol·g −1 after 4 h. According to the discussion of the structure, morphology, composition, and surface area, optical and photocatalytic properties of ZnO particles, it is obvious that the charge transfer efficiency and specific surface area are not the key effect factors in photocatalytic process, and the orderly changed morphologies lead to the transformation of active planes from (0 0 2) to (1 0 0) and the improvement of electron excitation ability, which may be favourable for the enhancement of photocatalytic H 2 evolution. The photocatalytic mechanism of ZnO was proposed.

Effect of different concentrations of the precursor on the properties of chemically induced ZnSe thin films

The properties of Zinc Selenide (ZnSe) thin films can be considerably varied by altering the concentration of precursor (Zinc acetate). As a starting material (precursor), zinc acetate and sodium selenosulphate were utilized. For solar applications, ZnSe is one of the most promising materials. The structural, chemical, optical, electrical, and photoelectric characteristics of ZnSe thin films were investigated on non-conducting glass substrates using a chemical bath deposition technique with varying concentration of zinc acetate (precursor) in an alkaline solution. Concentration affects the crystallinity, surface morphology, light absorption, photocurrent, and photo sensitivity of the films.

Zn Doping Effect on the Performance of Fe-Based Catalysts for the Hydrogenation of CO2 to Light Hydrocarbons.

In this work, we studied the role of zinc in the composition of supported iron-containing catalysts for the hydrogenation of CO2. Various variants of incipient wetness impregnation of the support were tested to obtain catalyst samples. The best results are shown for samples synthesized by co-impregnation of the support with a common solution of iron and zinc precursors at the same molar ratio of iron and zinc. Catalyst samples were analyzed by various methods: Raman, DRIFT-CO, TPR-H2, XPS, and UV/Vis. The introduction of zinc leads to the formation of a mixed ZnFe2O4 phase. In this case, the activation of the catalyst proceeds through the stage of formation of the metastable wustite phase FeO. The formation of this wustite phase promotes the formation of metallic iron in the composition of the catalyst under the reaction conditions. It is believed that the presence of metallic iron is a necessary step in the formation of iron carbides—that is, active centers for the formation and growth of chain in the hydrocarbons. This leads to an increase in the activity and selectivity of the formation of hydrocarbons in the process of CO2 hydrogenation.

Zinc Oxide Synthesis from Extreme Ratios of Zinc Acetate and Zinc Nitrate: Synergistic Morphology.

The synthesis of ZnO comprising different ratios of zinc acetate (ZA) and zinc nitrate (ZN) from the respective zinc precursor solutions was successfully completed via a simple precipitation method. Zinc oxide powders with different mole ratios of ZA/ZN were produced—80/1, 40/1, and 20/1. The crystallinity, microstructure, and optical properties of all produced ZnO powders were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-Vis-NIR spectrophotometry. The average agglomerated particle sizes of ZnO-80/1, ZnO-40/1, and ZnO-20/1 were measured at 655, 640, and 620 nm, respectively, using dynamic light scattering (DLS). The optical properties of ZnO were significantly affected by the extreme ratio differences in the zinc precursors. ZnO-80/1 was found to have a unique coral-sheet structure morphology, which resulted in its superior ability to reflect near-infrared (NIR) radiation compared to ZnO-40/1 and ZnO-20/1. The NIR-shielding performances of ZnO were assessed using a thermal insulation test, where coating with ZnO-80/1 could lower the inner temperature by 5.2 °C compared with the neat glass substrate. Due to the synergistic effects on morphology, ZnO-80/1 exhibited the property of enhanced NIR shielding in curtailing the internal building temperature, which allows for its utilization as an NIR-reflective pigment coating in the construction of building envelopes.

Structural and Optical Studies of Synthesized Semiconductor NixZn1-xS Nanostructure Thin Films for Optoelectronic Device Applications

Transition metal ions like Nickel doped ZnS semiconductor materials have a wide range of optoelectronic device applications. However, the doping concentration effect on the properties of NixZn1-xS has not been reported. This study, therefore, investigated the effects of nickel (Ni) doping concentration on the structural and optical properties of synthesized NixZn1-xS nanostructured thin films prepared by low-cost Chemical Spray Pyrolysis (CSP) technique. NixZn1-xS nanostructured thin films with a thickness of 320nm and different mole ratios (𝑥 = 0.00, 0.02, 0.04, 0.06 and 0.08,) were grown by the use of spray solution on hot glass substrates at a temperature of 300oC using CSP technique. The spray solutions contain nickel acetate, zinc acetate, and thiourea as precursors for Nickel, Zinc, and Sulphur, respectively. The influence of Ni doping concentration on the structural, optical, and morphological properties were investigated using X-ray diffraction (XRD), Ultraviolet-Visible spectroscopy (UV-vis) and Scanning Electron Microscopy (SEM) respectively. The XRD analysis indicated that all the prepared films retained the ZnS cubic zinc blend structure. SEM results show that the films are composed of well crystalline grains with various shapes and densely bound to each other. The UV-vis spectroscopy shows that transmittance is moderately high and increased with increasing Ni content. The average transmittance of NixZn1-xS are 61.3%, 62.8%, 63.9%, 67.6 and 69.6% for x = 0.00, 0.02, 0.04, 0.06 and 0.08, respectively. The bandgap of Ni-doped ZnS samples is low compared to the undoped, and the value increases gradually with increasing Ni concentration. Based on the results obtained, with the enhanced structural and optical properties, NixZn1-xS films could be a useful material in the future of optoelectronic applications.

Indium(II) Chloride as a Precursor in the Synthesis of Ternary (Ag-In-S) and Quaternary (Ag-In-Zn-S) Nanocrystals.

A new indium precursor, namely, indium(II) chloride, was tested as a precursor in the synthesis of ternary Ag–In–S and quaternary Ag–In–Zn–S nanocrystals. This new precursor, being in fact a dimer of Cl2In–InCl2 chemical structure, is significantly more reactive than InCl3, typically used in the preparation of these types of nanocrystals. This was evidenced by carrying out comparative syntheses under the same reaction conditions using these two indium precursors in combination with the same silver (AgNO3) and zinc (zinc stearate) precursors. In particular, the use of indium(II) chloride in combination with low concentrations of the zinc precursor yielded spherical-shaped (D = 3.7–6.2 nm) Ag–In–Zn–S nanocrystals, whereas for higher concentrations of this precursor, rodlike nanoparticles (L = 9–10 nm) were obtained. In all cases, the resulting nanocrystals were enriched in indium (In/Ag = 1.5–10.3). Enhanced indium precursor conversion and formation of anisotropic, longitudinal nanoparticles were closely related to the presence of thiocarboxylic acid type of ligands in the reaction mixture. These ligands were generated in situ and subsequently bound to surfacial In(III) cations in the growing nanocrystals. The use of the new precursor of enhanced reactivity facilitated precise tuning of the photoluminescence color of the resulting nanocrystals in the spectral range from ca. 730 to 530 nm with photoluminescence quantum yield (PLQY) varying from 20 to 40%. The fabricated Ag–In–S and Ag–In–Zn–S nanocrystals exhibited the longest, reported to date, photoluminescence lifetimes of ∼9.4 and ∼1.4 μs, respectively. It was also demonstrated for the first time that ternary (Ag–In–S) and quaternary (Ag–In–Zn–S) nanocrystals could be applied as efficient photocatalysts, active under visible light (green) illumination, in the reaction of aldehydes reduction to alcohols.

Chromium Ion Accumulations from Aqueous Solution by the Eichorinia crassipes Plant and Reusing in the Synthesis of Cr‐Doped ZnO Photocatalyst

The Cr‐doped ZnO photocatalysts were synthesized through the chromium ion accumulations by water hyacinth (Eichhornia crassipes). In the preparation process, the plant tissues were immersed in different sample flasks containing chromium precursors for 1, 2, 4, 6, and 8 days. The plant tissue containing chromium ion was mixed with zinc precursor followed by calcinations. For simplicity, the prepared Cr‐doped ZnO samples with the plant immersed for 1, 2, 4, 6, and 8 days were abbreviated as D1, D2, D4, D6, and D8, respectively. Moreover, pure ZnO was also prepared without the water hyacinth plant accumulated with chromium ion for comparison purposes. The powder sample characterizations were performed and evaluated in the degradation of methylene blue (MB). The Cr‐doped ZnO sample (D1) degrades 80% of MB dye while the D2, D4, D6, D8, and pure ZnO samples degrade only 74, 76, 79, 73, and 25%, respectively. On the other hand, without the addition of catalysts (blank), there was no significant degradation of MB dye within 90 min irradiation. Therefore, the degradation performance of Cr‐doped ZnO in the presence of optimum amount of chromium dopant and water hyacinth is highly improved than that of pure ZnO. The catalytic improvement may be as a result of reducing the photogenerated electron and hole recombination rates due to the presence of dopants. Moreover, the presence of the Eichhornia crassipes plant in the synthesis of Cr‐doped ZnO could also prevent further aggregations and particle size growth and enhance the porosity after calcination.