Thermal Synthesis Method Research Articles

Construction of magnetically separable S-scheme BiFeO3/Cl-g-C3N4 heterostructure photocatalyst for simultaneous removal of Cr(Ⅵ) and tetracycline in aqueous solution: Performance and mechanism insight

A green, efficient and recyclable magnetic BiFeO3/Cl-g-C3N4 photocatalyst was prepared for the simultaneous removal of Cr(Ⅵ) and tetracycline (TC) from water by wet chemical and thermal synthesis methods. Experimental results revealed that BiFeO3/Cl-g-C3N4 achieved a removal efficiency of 96.1 % for Cr(Ⅵ) and 98.2 % for TC under visible light irradiation for 50 min at pH 6. The results of the work function, differential charge density, UV–vis DRS, PL, PC and EIS tests indicate the formation of S-scheme heterojunctions between BiFeO3 and Cl-g-C3N4, which exhibits superior carrier separation and migration efficiency. The evidence for interfacial charge transfer from BiFeO3 to Cl-g-C3N4 within BiFeO3/Cl-g-C3N4 was further corroborated by means of ISIXPS, EPR and KPFM. Moreover, calculations of the density of states demonstrate that the introduction of Cl enhances the reduction capability of BiFeO3/Cl-g-C3N4. Results from ESR tests and trapping experiments has demonstrated that the singlet oxygen (1O2) and electrons are the primary active species. Furthermore, the high removal rates of TC and Cr(VI) from industrial wastewater and groundwater, coupled with the lower ecotoxicity of TC degradation intermediates, indicate that BiFeO3/Cl-g-C3N4 has the potential for practical applications. After five cycles, the BiFeO3/Cl-g-C3N4 still removed 90.5 % of TC and 96 % of Cr(Ⅵ).

Microwave-Assisted Ultrafast Synthesis of Bimetallic Nickel-Cobalt Metal-Organic Frameworks for Application in the Oxygen Evolution Reaction.

Herein, a series of monometallic Ni-, Co- and Zn-MOFs and bimetallic NiCo-, NiZn- and CoZn-MOFs of formula M2(BDC)2DABCO and (M,M')2(BDC)2DABCO, respectively, (M, M'=metal) with the same pillar and layer linkers 1,4-diazabicyclo[2.2.2]octane (DABCO) and benzene-1,4-dicarboxylate (BDC) were prepared through a fast microwave-assisted thermal conversion synthesis method (MW) within only 12 min. In the bimetallic MOFs the ratio M:M' was 4 : 1. The mono- and bimetallic MOFs were selected to systematically explore the catalytic-activity of their derived metal oxide/hydroxides for the oxygen evolution reaction (OER). Among all tested bimetallic MOF-derived catalysts, the NiCoMOF exhibits superior catalytic activity for the OER with the lowest overpotentials of 301 mV and Tafel slopes of 42 mV dec-1 on a rotating disk glassy carbon electrode (RD-GCE) in 1 mol L-1 KOH electrolyte at a current density of 10 mA cm-2. In addition, NiCoMOF was insitu grown in just 25 min by the MW synthesis on the surface of nickel foam (NF) with, for example, a mass loading of 16.6 mgMOF/gNF, where overpotentials of 313 and 328 mV at current densities of 50 and 300 mA cm-2, respectively, were delivered and superior long-term stability for practical OER application. The low Tafel slope of 27 mV dec-1, as well as a low reaction resistance from electrochemical impedance spectroscopy (EIS) measurement (Rfar=2 Ω), confirm the excellent OER performance of this NiCoMOF/NF composite. During the electrocatalytic processes or even before upon KOH pre-treatment, the MOFs are transformed to the mixed-metal hydroxide phase α-/β-M(OH)2 which presents the active species in the reactions (turnover frequency TOF=0.252 s-1 at an overpotential of 320 mV). Compared to the TOF from β-M(OH)2 (0.002 s-1), our study demonstrates that a bimetallic MOF improves the electrocatalytic performance of the derived catalyst by giving an intimate and uniform mixture of the involved metals at the nanoscale.

Cucurbit[7]uril-Modified Nano SiO2 for Efficient Separation of Crude Oil Emulsions: Properties and Demulsification Mechanism.

Demulsification of crude oil emulsion is an obvious problem in the whole of petroleum engineering, which needs to be dealt with urgently. In this paper, a supramolecular material Cucurbit[7]uril-SiO2 (CB-SiO2) synthesized with excellent demulsification efficiency (DE) on O/W emulsion was synthesized by a simple thermal synthesis method. The microscopic morphology and structure were investigated through modern characterization techniques. Furthermore, its stability, dynamic interfacial tension (IFT), and wettability (three-phase contact angle (CA)) were systematically investigated, and the demulsification efficiency of different conditions on crude oil emulsion was also investigated. Reassuringly, these results showed that when the temperature was 70 °C, the demulsification dosage was close to 600 mg/L and remained unchanged for 90 min; the demulsification efficiency is 2.2 times compared with the unmodified material, up to 93.63%. In addition, a plausible demulsification mechanism was proposed, which is that CB-SiO2 can adsorb and disrupt the oil-water interface, leading to oil-water separation and promoting demulsification. It is a promising demulsification material for the oil industry demulsification.

Study on the preparation of CdS/TiO2 corn straw biochar composite materials for photocatalytic reduction of CO2 and collaborative H2 production.

A thermal synthesis method was employed in this work to prepare CdS/TiO2 corn straw biochar photocatalytic composite materials suitable for synergistic hydrogen production with the photocatalytic reduction of CO2. The structure and synergistic reaction of these composite materials were characterized by its photogenerated electron transfer process. Compared with pure TiO2, the energy band gap of the optimal CdS/TiO2 corn straw biochar composite material was reduced to 2.89eV. The heterostructure coupling between TiO2 and CdS in the biochar accelerated the transfer of photogenerated electrons and reduced the recombination rate of photogenerated electrons and holes. Under visible light irradiation, the photocatalytic H2 yield of this CdS/TiO2 corn straw-derived biochar composite material was 1200µmol·h-1·g-1, the CO yield was 150µmol·h-1·g-1, and the CH4 yield was 55µmol·h-1·g-1. The key to this synergistic reaction is the formation of heterojunctions between CdS and TiO2 as well as the rapid oxidation of holes in the composite material caused by the doping of biochar.

HYBRID ORGANIC–INORGANIC ASSEMBLIES BASED ON COORDINATION METAL–LIGAND FRAGMENTS: SYNTHESIS, PROPERTIES, APPLICATION IN CHROMATOGRAPHY

The data on the synthetic methods of metal-organic frameworks (MOF) based on the coordination compounds of metals, including germanium, with the polydentate aromatic acids, their properties and applications are systemised in the paper. The prospect of using such types of MOFs to determine the highly toxic organic pollutants such as polycyclic aromatic hydrocarbons (PAHs) has been identified. Due to their unique properties, including large surface area, uniformly structured nanoscale cavities, tunable pore sizes and thermal stability MOFs are promising materials for use in analytical chemistry. They have been used in air sampling, as a stationary phase in chromatography, and as sorbents for solid-phase extraction, solid-phase microextraction, and magnetic solid-phase extraction. Depending on the structure of the ligands, MOFs can provide molecular recognition through different types of interactions of a wide range of compounds, such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), pyrethroids, nitrosamines and parabens, that are immunosuppressors, endocrine disruptors and cancerogenic compounds. For example, MOFs adsorb hydrophobic organic compounds (e.g., PAHs, PCBs) due to π-π stacking and hydrophobic interactions with organic linkers. Whereas the extraction of organic compounds with hydrophilic groups (for example, nitrosamines) occurs due to electrostatic interaction and hydrogen bonds. The most effective methods of synthesis of the considered type MOF are hydro(solvo)thermal synthesis and mechanochemical methods modified by adding a small amount of solvents. The slow diffusion methods are advisable to use to obtain crystals suitable for single-crystal X-ray diffraction.

Hidro(solvo)termal destekli silika aerojellerin sentezi, modifikasyonu ve onların adsorpsiyon çalışmalarında kullanımı

The hydro(solvo)thermal synthesis method was used to successfully synthesize bare silica aerogels and nano- and microparticle-embedded silica aerogels containing SiO2 and carbon microparticles in this study. New groups were added to these structures through modification. In the study, first, the effect of the variables was systematically examined to determine the optimum conditions. The most suitable recipe for silica aerogel was created. SiO2 and CP particles were synthesized, and modified silica aerogels were prepared with these particles and agents containing amine. For the characterization of synthesized silica aerogel, particles (SiO2, CP) and particle-embedded silica aerogels, TGA, SEM, DLS and BET-BJH techniques were used. These structures were used as adsorbent in environmental applications such as removing organic pollutants like 4-nitro phenol, methylene blue, Victoria blue, bromophenol blue etc. from aqueous media. In this environmental application, the adsorption capacity (mg/g) was determined by using UV-vis spectroscopy. The prepared structures are good adsorbents, and the adsorption capacity can be increased 18-fold with modification.

Emerging Porous Two-Dimensional Materials: Current Status, Existing Challenges, and Applications.

Two-Dimensional (2D) materials have attracted immense attention in recent years. These materials have found their applications in various fields, such as catalysis, adsorption, energy storage, and sensing, as they exhibit excellent physical, chemical, electronic, photonic, and biological properties. Recently, researchers have focused on constructing porous structures on 2D materials. Various strategies, such as chemical etching and template-based methods, for the development of surface pores are reported, and the porous 2D materials fabricated over the years are used to develop supercapacitors and energy storage devices. Moreover, the lattice structure of the 2D materials can be modulated during the construction of porous structures to develop 2D materials that can be used in various fields such as lattice defects in 2D nanomaterials for enhancing biomedical performances. This review focuses on the recently developed chemical etching, solvent thermal synthesis, microwave combustion, and template methods that are used to fabricate porous 2D materials. The application prospects of the porous 2D materials are summarized. Finally, the key scientific challenges associated with developing porous 2D materials are presented to provide a platform for developing porous 2D materials.

Effect of Water-Soluble CMC/SBR Binder Ratios on Si-rGO Composites Using µm- and nm-Sized Silicon as Anode Materials for Lithium-Ion Batteries

Silicon-containing materials are still the most promising alternatives to graphite as the negative electrodes of lithium-ion batteries. However, the different Li+ storage mechanism combined with the high capacity result in new requirements for the passive electrode components, such as the binder. To ensure sufficient cycling stability, silicon must be embedded in a suitable carbonaceous matrix. For this purpose, we used a simple ball milling process with reduced graphene oxide (rGO) to produce Si-rGO composites with µm- and nm-sized silicon particles. The rGO was synthesized previously from a two-step thermal synthesis method developed in-house. Subsequently, electrodes with varying CMC/SBR ratios (3:1, 1:1, and 1:3) were prepared from the composites containing the different Si particle sizes. It was found that the optimal binder ratio depends on the size of the Si particles. For the nm-Si-rGO composite, a CMC/SBR ratio of 3:1 results in a total capacity over 51 cycles of 20.6 Ah g−1, which means an improvement of 20% compared to CMC/SBR = 1:3 (17.1 Ah g−1). In contrast, we demonstrate that for µm-Si-rGO composites with an optimal CMC/SBR ratio of 1:1 (13.0 Ah g−1), compared to nm-Si-rGO, a higher SBR content is beneficial for the cycling behavior. Moreover, a comparison with graphite from the literature indicates that a rGO-matrix reduces the need for SBR.

Preparation of TiO2/WO3-corn straw based graphene-like composite and its low light catalytic hydrogen production performance and mechanism

In this paper, TiO2/WO3 corn straw graphene-like photocatalyst composite suitable for low light catalytic hydrogen production is prepared by one pot thermal synthesis method. The morphology and structural characteristics of TiO2/WO3 corn straw graphene-like compounds are analyzed. Based on the photoelectric characteristics and density functional theory simulation results, the energy band of TiO2/WO3 corn straw graphene-like composite material is reduced to 2.32 eV compared with pure TiO2 and WO3. The transfer rate of photogenerated carriers is accelerated, and the p-n heterostructure between TiO2 and WO3 interacts with graphene to promote the transfer of photogenerated electrons. Moreover, some photogenerated electrons reside on the graphene surface. Consequently, under low light irradiation, the efficiency of photogenerated electron transfer is increased and the hydrogen production performance is improved. The photocatalytic experiment showed that the hydrogen production rate of TiO2/WO3 corn straw graphene-like composite under low light irradiation is only 10% lower than that under visible light irradiation. Furthermore, the addition of graphene increases the specific surface area of the composite photocatalyst, which makes the composite material more adaptable to low light and improves its feasibility for industrial mass production.

Increasing the number of active centers and matching acid micro-environment by the design of phosphorus immobilized for boosting catalytic activity

A series of MnMoP catalysts were prepared by ionic liquid assisted thermal synthesis method and characterized by Powder X-ray diffraction, Fourier Transform Infrared Spectrometer, Scanning Electron Microscope, X-ray Photoelectron Spectroscope and NH3-Temperature Programmed Desorption. The catalytic performance of MnMoP catalysts for the synthesis of cyclohexene oxide (CHO) was studied. The results showed that phosphorus was fixed via ionic liquid, which could improve the catalytic performance of the catalysts. Under the optimal conditions, MnMoP-80 catalyst showed the best catalytic performance with the cyclohexene conversion of 97.5% and CHO selectivity of 93.9%. Meanwhile, we have deduced that the reaction was mainly carried out according to the epoxidation pathway over MnMoP catalyst.

Preparation of corn stover hydrothermal carbon sphere-CdS/g-C3N4 composite and evaluation of its performance in the photocatalytic co-reduction of CO2 and decomposition of water for hydrogen production

In this paper, a composite photocatalyst based on g-C3N4/CdS/corn straw hydrothermal carbon spheres was prepared by one-pot thermal synthesis method and applied for photocatalytic reduction of CO2 and hydrogen production. The morphology and structure of CdS/g-C3N4/ corn straw hydrothermal carbon spheres were characterized, which confirmed that the corn straw hydrothermal carbon spheres were successfully loaded into the heterojunction of g-C3N4 and CdS nanosheets. Through the study of photoelectric characteristics and DFT simulation, it was found that the energy band of g-C3N4/CdS/corn straw hydrothermal carbon spheres composite is reduced by 2.04 eV compared with that of pure g-C3N4 and CdS, and the photogenerated carrier transfer rate is accelerated. The Z-scheme heterostructure between g-C3N4 and CdS and the graphitized hydrothermal carbon spheres increase the surface active sites of the composite, leading to the generation of synergistic photocatalytic reaction. The photocatalytic experiment showed that g-C3N4/CdS/corn straw hydrothermal carbon spheres composite exhibited synergistic photocatalytic performance, while pure g-C3N4 and CdS did not. When the mass ratio of g-C3N4/CdS/corn straw hydrothermal carbon spheres was 1:0.1:0.5, the synergistic reaction efficiency was the highest, and the H2 yield was 250 μ mol·h−1·g−1, CO yield was 100 μ mol·h−1·g−1, and CH4 yield was 25 μ mol·h−1·g−1. By calculating the Gibbs free energy of the photocatalytic reaction and determining the possible mechanism of the synergistic reaction of g-C3N4/CdS/corn straw hydrothermal carbon spheres, it was inferred that the key step in the reaction was generation of CO.

Facile fabrication of porous Ag cubes on Cu substrate for Raman Sensor

• Cu 2 O with cubic structure is fabricated by a facile electrochemical process. • Cu 2 O serves as scarifying template for the synthesis of cubic Ag with porous structure. • The high surface area of porous Ag cubes enables more molecule adsorbed on its surface. • This porous Ag material is a promising material in Raman Sensor. Ag microcubes with a hierarchical porous structure were successfully prepared by a galvanic replacement reaction (GRR) on Cu foil through a subsequently facile two-step process. Firstly, and most importantly, Cu 2 O nano cubes which serves as sacrificial template were synthesized by anodic oxidation of Cu using the dilute hydrochloric acid as an electrolyte for the first time. Compared with traditional thermal synthesis method for the Cu 2 O cubes, the electrochemical method is direct, convenient and cost-effective. Then, the cubic Cu 2 O covered Cu substrate reacts with AgNO 3 and forms porous Ag micro-cubes. The porous Ag with three-dimensional structure is a promising material in Raman Sensor.

Facile bio-fabrication of ZnO@AC nanoparticles from chitosan: Characterization, hydrogen generation, and photocatalytic properties

In this work, activated carbon-supported zinc oxide nanoparticles (ZnO@AC NPs) were studied using the thermal synthesis method. The activated carbon-supported zinc oxide catalyst was characterized by UV–Vis spectrometry techniques, Fourier Transform Infrared Spectrophotometer (FTIR), Transmissive electron microscopy (TEM), and X-ray diffraction (XRD) methods. XRD characterization measurements showed that the average size of the crystal NPs was 6.89 nm. According to the TEM analysis results, the nanoparticles' average size was 11.411 nm, and the particles had a spherical structure. The catalytic properties of the synthesized material were determined using the sodium borohydride methanolysis reaction. A kinetic study was performed regarding the effects of temperature, catalyst, and substrate concentration on the methanolysis reaction. Reusability experiments showed that the catalyst had excellent catalytic activity (85%), stability, and selectivity. As a result of the kinetic study, activation energy, enthalpy (ΔH), entropy (ΔS), and hydrogen production rate activation parameters were found to be 42.52 kJ/mol, 39.98 kJ/mol, −181.42 J/mol.K, 1257.69 mL/min. g, respectively. Also, the photocatalytic activity of ZnO@AC NPs was analyzed against Rhodamine B (RhB) dye, and the maximum degradation percentage was observed to be 76% at 120 min. This study aimed to develop the ZnO@AC NPs into an efficient photocatalyst to prevent industrial wastewater pollution and as a catalyst for hydrogen synthesis as an alternative energy source.

Preparation of Heteromorphic Ni Decorated Fe‐Containing Carbon Nanofibers as Efficient and Low‐Cost Counter Electrodes for Dye‐Sensitized Solar Cells

AbstractIn the field of dye‐sensitized solar cells (DSSCs), although Pt is commonly used as counter electrode materials owing to its great electrocatalytic activity and conductivity, the high price and small reserves of Pt limit its large‐scale application. In this paper, heteromorphic Ni decorated Fe‐containing carbon nanofibers (Ni/NiO@Fe‐CNFs) was prepared by a thermal synthesis method, and applied as composite counter electrode materials for DSSCs. It was found that the as‐synthesized Ni/NiO@Fe‐CNFs shows better electrocatalytic activity than that of Fe‐CNFs and CNFs for the reduction reaction of triiodide to iodide. The improved electrocatalytic activity is not only attributed to the introduction of Fe2O3 to form Fe‐CNFs, but also attributed to the heteromorphic Ni decoration and their synergistic effect. The photoelectric conversion efficiency of DSSCs with Ni/NiO@Fe‐CNFs counter electrode is 4.81 %, much higher than that of CNFs (0.62 %) and Fe‐CNFs counter electrode (3.65 %), and comparable to the value of Pt counter electrode (5.10 %). Accordingly, the Ni/NiO@Fe‐CNFs is expected to be a potential counter electrode material to replace Pt.

Experimental investigations and kinetics of hydrogen oxidation by oxygen in the media of carbon dioxide under elevated pressure at fiber-glass Pt/Pd catalysts

The study is dedicated to the performance of glass-fiber catalysts (GFCs) in the practically important reaction of hydrogen oxidation by oxygen in the media of carbon dioxide at elevated pressures. The samples of the catalysts were synthesized using Pt and Pd as active metals and thermostable high-silica glass-fiber textiles both unpromoted and promoted by Zr. The used catalyst preparation methods include surface thermal synthesis and leaching/impregnation approaches. All three tested samples showed approximately equal activity, but the preference was given to Pt-based GFC synthesized by means of surface thermal synthesis method because it uses the much cheaper and widely available glass-fiber textile instead of rare and expensive Zr-promoted materials. Resource testing of this catalyst for more than 200 hours demonstrated its high stability. The reaction rate may be described by kinetic equation corresponding to mass-action law with linear dependence upon the reaction pressure. The studied GFC may be arranged into structured cartridges with low pressure drop and highly intensive heat and mass transfer under the commercial process conditions, so its further practical application looks promising.

Synthesis of g-C3N4/WO3-carbon microsphere composites for photocatalytic hydrogen production

In this paper, a g-C 3 N 4 /WO 3 -carbon microsphere composite-based photocatalyst was successfully prepared by a one-pot thermal synthesis method for sunlight driven decomposition of water to produce hydrogen. The results show that the g-C 3 N 4 /WO 3 -carbon microspheres had better photocatalytic properties and stability. Under visible light and sunlight irradiation, the hydrogen production efficiency of the photocatalytic decomposition of water was 107.75 times and 70.54 times greater than that of pure g-C 3 N 4 , respectively. The experimental and characterization results show that g-C 3 N 4 and WO 3 formed a Z-scheme heterojunction on the surface of the g-C 3 N 4 /WO 3 -carbon microsphere composite-based photocatalyst. Carbon microspheres modified on g-C 3 N 4 nanosheets and WO 3 had good conductivity and promoted the transfer of photogenerated electrons in g-C 3 N 4 nanosheets. The addition of carbon microspheres increased the specific surface area of the composite photocatalyst. The g-C 3 N 4 /WO 3 -carbon microsphere composite-based photocatalyst showed strong adaptability to the fluctuating light intensity, providing feasibility for industrialized mass production. • g-C 3 N 4 /WO 3 -carbon microsphere composites were prepared. • The g-C 3 N 4 /WO 3 -carbon microsphere composites exhibited high hydrogen production. • The synergy of g-C 3 N 4 /WO 3 and carbon microspheres improved the catalytic activity. • The biomass carbon microsphere increased the electron transfer rate of composites.

Economic Evaluation of Cobalt Ferrite (CoFe2O4) Nanoparticles Using Thermal Decomposition Synthesis Method

The purpose of this study was to determine the technical and economic feasibility of a project to manufacture CoFe2O4 nanoparticles using the thermal decomposition synthesis method on an industrial scale. The method used in economic evaluation is to compare several parameters such as gross profile margin (GPM), payback period (PBP), breakeven points (BEP), internal rate return (IRR), cumulative net present value (CNPV), return on investment (ROI), and profitability index (PI). The results show that the production of CoFe2O4 nanoparticles is profitable on an industrial scale with a relatively lower selling price than the market price and a relatively small size. This project can run within nine years and the investment will be profitable within 2 years according to PBP results.

Water-retaining properties of NCZ composite dust suppressant and its wetting ability to hydrophobic coal dust

Coal dust is a primary threat to underground coal miners. The most common approach to control coal dust is hydraulic methods, such as water spray and coal seam water injection. To improve the dust suppressant efficiency of hydraulic methods, a novel chemical composite dust suppressant, called NCZ, was prepared in this study using calcium chloride (CaCl2), magnesium chloride (MgCl2), and nonionic surfactants using a thermal synthesis method. The water-retaining properties of NCZ powder and its solutions were characterized using the water absorption rate (WAR) and evaporation rate (ER), respectively, and the wetting abilities of the NCZ solutions on coal dust were tested using the initial contact angle (ICA) and sink rate (SR). The results indicate that the NCZ solutions have anti-evaporation effects, and the ER of the solution with a 20.0 wt% NCZ is reduced by 11.7% compared with that of clean water. Furthermore, NCZ solutions have remarkable enhancement effects on the wettability of coal dust. The ICA and SR of clean water and the NCZ solution at 20.0 wt% are 141.9° and 0 mg/s, and 29.3° and 1.46 mg/s, respectively. Finally, quantitative relationships between the solution surface tension and the ICA and IR were established using the least squares method. This study provides a new product for dust suppression in underground mines, which is significant for the optimum applied concentration of dust suppressant in mining operations.

Promoting carrier separation efficiently by macroscopic polarization charges and interfacial modulation for photocatalysis

Extraction or injection of charges through the interface in hybrid catalysts is a fascinating strategy for steering charge carrier transfer in solar energy conversion applications. Instead of interfacial charges regulation, we adopt intrinsic spontaneous polarization-modulated internal electric field to drive photo-generated carriers separation and transfer in both the bulk and surface for photocatalysis. Herein, we first report a series of nano-composites made of perovskiteferroelectric BiFe0.9Mn0.1O3 and orthorhombic phase α-MoO3 semiconductor (BFMO-xM, x = 0, 5%, 10%, 15%) via two-step thermal synthesis method. With × = 10%, the heterostructure exhibits significantly enhancement of optical response and photo-decomposion tetracycline capacity under sunlight compared with pure BFMO and M. The improved photocatalysis is attributed to the superimposed actions of the Z-scheme charge transfer through interface and the polarization field in BFMO for the anti-recombination of photo-excited electron-hole pairs. This work indeed offers a strategic design over multicomponent catalyst by consider the synergy of polarization charges and interfacial charge transmission for solar energy conversion.

Optical Properties of Cd-Free Quantum Dots-Based Fluorescent Film

CuInS2/ZnS Cd-free quantum dots (QDs) have many characteristics, such as high quantum yield (QY), wide emission peak and adjustable light color. They are suitable for optical conversion materials and applies in solid-state lighting (SSL). However, they are not easily dispersed during encapsulation, resulting in the deviation of light color out of the white light area after encapsulation. In this study, we use thermal injection synthesis method to prepare CuInS2/ZnS and CuInS2/ZnS:Al QDs. In order to improve the dispersion of QDs, solution type of QD/PS-PE-BR-PS copolymer (SEBS) mixture was prepared by mixing QD and SEBS with different ratios (10, 20, and 30 wt%) to form a fluorescent film. The experimental results show that the emission wavelengths and QY of CuInS2/ZnS and CuInS2/ZnS:Al QDs are 533 nm, 84 % and 536 nm, 97 %, respectively. The emission wavelength of CuInS2/ZnS-based fluorescent film is 574 nm, while CuInS2/ZnS:Al-based fluorescent film is 582 nm. The CRI, luminous efficacy, chromaticity coordinates and correlated color temperature of 20 wt% CuInS2/ZnS-based fluorescent film excited by blue chip is 64, 42 lm/W, (0.33, 0.32), and 5443 K, respectively. On the other hand, we find that the CRI of CuInS2/ZnS:Al-based fluorescent film can be improved from 64 to 73, and the luminous efficacy is 51 lm/W.