Preparation and photoelectric properties of cadmium sulfide quantum dots

Cadmium sulfide quantum dots(CdS QDs) are widely used in solar cells, light emitting diodes, photocatalysis, and biological imaging because of their unique optical and electrical properties. However, there are some drawbacks in existing preparation techniques for CdS QDs, such as protection of inert gas, lengthy reaction time, high reaction temperature, poor crystallinity, and non-uniform particle size distribution. In this study, we prepared CdS QDs by liquid phase synthesis under ambient room temperature and atmospheric pressure using sodium alkyl sulfonate, CdCl_2, and Na_2S as capping agent, cadmium, and sulfur sources respectively. This technique offers facile preparation, efficient reaction, low-cost, and controllable particle size. The as-prepared CdS QDs exhibited good crystallinity, excellent monodispersity, and uniform particle size. The responsivity of CdS QDs-based photodetector is greater than 0.3 μA/W, which makes them suitable for use as ultra-violet(UV) detectors.

Synthesis,Crystal Structure and Photoluminescence Property of Potassium Terbium Polyphosphate KTb(PO3)4

The potassium terbium polyphosphate crystal KTb（PO3）4 has been synthesized using a high temperature solution reaction method. The structure and composition were characterized by single-crystal X-ray diffraction, powder X-ray diffraction and elemental analysis. The compound crystallizes in the monoclinic space group P21/n with a=10.3182（6）, b=8.9129（5）, c=10.7940（6） , β=105.993（1）o, V=954.3 3, Z=4, Mr=513.91, Dc=3.577 g/cm3, μ=8.585 mm（-1）, F（000）=960, S=0.955,（Δρ）max=1.380,（Δρ）min=–3.428 e/3, the final R=0.0301 and w R=0.0400 for 2301 observed reflections with I 〉 2σ（I）. In addition, pure powder of isostructural Rb Tb（PO3）4 was synthesized in order to investigate the optical property. Photoluminescence measurements show that both crystals ATb（PO3）4（A=K（1）, Rb（2）） are promising candidates to become solid-state visible green light-emitting sources.

The Synthesis and Characterization of Dodecylbenzenesulfonic Ion Intercalated Layered Double Hydroxides(Ldhs)

Layered double hydroxides(LDHs)are aclass of layered inorganic materials that consist ofstructurally positively charged layers and exchange-able anions in the interlayer gallery for charge bal-ance.The delamination of LDHs is decided by syn-thesis method to some extent.In this work,LDHsare synthesized via three different routes and theirdelamination properties are characterized.Co-precipitation methodion-exchange meth-

The Preparation and Sintering Behavior of Ce_(0.8)Sm_(0.2)O_(2-d) Electrolyte and(NiO-CuO)/Ce_(0.8)Sm_(0.2)O_(2-d) Anodes for Solid Oxide Fuel Cells

The co-pressing and co-firing processes are often used to prepare the anode-electrolyte half cells for solid oxide fuel cells(SOFCs).To get a half cell without cracks,the sintering behavior of electrolyte and anode layers must be controlled carefully.In this work,the sintering behavior

The Synthesis and Characterization of Sr-Y Doped BaCeO_3

Doped BaCeO_3 is a kind of proton conductor which exhibits high electrical conductivities at relatively low operating temperatures.It has been used as the electrolyte materials for proton ceramic fuel cells,and the effects of dopants on the sinter-ability and electrical performance are critical factors.

The Synthesis and Characterization of Sr-Cu-Fe Doped La_2NiO_4

Doped La_2NiO_4 are promising cathode materials for solid oxide fuel cells(SOFCs)which are environment friendly energy conversion devices.In this work,the synthesis of Sr,Fe and Cu doped La_2NiO_4 and the effects of dopants on phase formation during calcination and on

Better Oxygen Transport Properties and Chemical Stability of La_2NiO_4 Compared with Those of Sr-Fe Doped Lagao_3

Mixed conductors of oxygen ion and electron are important materials.They have been used as oxygen permeation membranes or electrodes of fuel cells.Doped LaGaO_3 and La_2Ni O_4 are both mixed conductors,but they have different crystal structures which will result in different

SnS_2 quantum dots: Facile synthesis, properties,and applications in ultraviolet photodetector

Tin sulfide quantum dots(SnS_2 QDs) are n-type wide band gap semiconductor. They exhibit a high optical absorption coefficient and strong photoconductive property in the ultraviolet and visible regions. Therefore, they have been found to have many potential applications, such as gas sensors, resistors, photodetectors, photocatalysts, and solar cells. However, the existing preparation methods for SnS_2 QDs are complicated and require a high temperature and high pressure environments; hence they are unsuitable for large-scale industrial production. An effective method for the preparation of monodispersed SnS_2 QDs at normal temperature and pressure will be discussed in this paper. The method is facile, green,and low-cost. In this work, the structure, morphology, optical, electrical, and photoelectric properties of SnS_2 QDs are studied. The synthesized SnS_2 QDs are homogeneous in size and exhibit good photoelectric performance. A photoelectric detector based on the SnS_2 QDs is fabricated and its J–V and C–V characteristics are also studied. The detector responds under λ = 365 nm light irradiation and reverse bias voltage. Its detectivity approximately stabilizes at 1011 Jones at room temperature. These results show the possible use of SnS_2 QDs in photodetectors.

Electronic structure of O-doped SiGe calculated by DFT+U method

To more in depth understand the doping effects of oxygen on SiGe alloys, both the micro-structure and properties of O-doped SiGe （including： bulk, （001） surface, and （110） surface） are calculated by DPT ＋ U method in the present work. The calculated results are as follows. （i） The （110） surface is the main exposing surface of SiGe, in which O impurity prefers to occupy the surface vacancy sites. （ii） For O interstitial doping on SiGe （110） surface, the existences of energy states caused by 0 doping in the band gap not only enhance the infrared light absorption, but also improve the behaviors of photo-generated carriers. （iii） The finding about decreased surface work function of O-doped SiGe （110） surface can confirm previous experimental observations. （iv） In all cases, O doing mainly induces the electronic structures near the band gap to vary, but is not directly involved in these variations. Therefore, these findings in the present work not only can provide further explanation and analysis for the corresponding underlying mechanism for some of the experimental findings reported in the literature, but also conduce to the development of μc-SiGe-based solar ceils in the future.

Ultrasonic Effect on Fabrication of Intercalated Mg Al-LDH/PVA Nanocomposite Via Exfoliation-adsorption Route

Preparation for Glycine-Mg/Al-Layered dou-ble hydroxide(LDH-G)/PVA nanocompositeswas carried out via exfoliation-adsorption routebased on exfoliation of LDH-G in formamide.Theeffect of ultrasonic treatment on the fabrication ofLDH-G/PVA nanocomposites was investigated,and the thermal stability of PVA containing the na-no-scale dispersed LDH-G was analyzed.The re-sults of XRD suggest that chains of PVA with

Rearrangement on surface structures by boride to enhanced cycle stability for LiNi0.80Co0.15Al0.05O2 cathode in lithium ion batteries

The side reaction between the active material and liquid-electrolyte cause structural damage and particle pulverization is one of the important factors leading to the capacity decay of LiNi0.80Co0.15Al0.05O2(NCA)materials in Li ion batteries(LIBs).Surface modification is an effective strategy for NCA cathodes,which could alleviate the degradation associated with surface processes.Herein,a surface structure rearrangement of NCA cathode secondary particles was reported by in-situ forming a solid electrolyte LiBO2.The LiBO2 is beneficial for alleviating the stress during charge/discharge process,thereby slowing down the rate of cracks formation in the secondary particles,which facilitates the Li+de-intercalation as well as prevents penetration of the liquid-electrolyte into the interior of the particles.As a result,the surface structure rearrangement NCA(RS-NCA)delivers a high discharge capacity of 202.5 m Ah g^-1 at 0.1 C,and exhibits excellent cycle stability with discharge capacity retaining 148 m Ah g^-1 after 200 cycles at 2 C.This surface structure rearrangement approach provides a new viewpoint in designing high-performance high-voltage LIBs.

Extended π-conjugated N-containing heteroaromatic hexacarboxylate organic anode for high performance rechargeable batteries

Organic electrode materials are desirable for green and sustainable Li-ion batteries(LIBs) due to their light-weight, low cost, abundance and multi-electron transfer reactions during battery operation. However, the successful utilization of organic electrodes is hindered by their poor electrical conductivity and low cyclic stability. Herein, a facile synthesis of π-conjugated N-containing heteroaromatic hexacarboxylate(Li6-HAT) compound and its electrochemical performance as an anode material in LIBs is reported.The as-synthesized Li6-HAT electrode renders an ultrahigh initial capacity of 1126.3 m Ah g^(-1) at the current density of 100 m A g^(-1). Moreover, π-conjugated N-containing heteroaromatic center provide excellent reversibility of(de)lithiation process, resulting in excellent capacity retention. Furthermore, a combination of density functional theory(DFT) calculations, in-situ Fourier transform infrared(FTIR) and ex-situ X-ray photoelectron spectroscopy(XPS) characterization reveal that the π-conjugated nitrogen and carboxyl oxygen act as electrochemically active sites during the charge/discharge process. The current work provides novel insights into the charge storage mechanism of organic electrodes and opens up avenues for further development and utilization of organic electrodes in Li-ion batteries.

Progress of the key materials for organic solar cells

Organic solar cells have attracted academic and industrial interests due to the advantages like lightweight,flexibility and roll-to-roll fabrication.Nowadays,18%power conversion efficiency has been achieved in the state-of-the-art organic solar cells.The recent rapid progress in organic solar cells relies on the continuously emerging new materials and device fabrication technologies,and the deep understanding on film morphology,molecular packing and device physics.Donor and acceptor materials are the key materials for organic solar cells since they determine the device performance.The past 25 years have witnessed an odyssey in developing high-performance donors and acceptors.In this review,we focus on those star materials and milestone work,and introduce the molecular structure evolution of key materials.These key materials include homopolymer donors,D-A copolymer donors,A-D-A small molecular donors,fullerene acceptors and nonfullerene acceptors.At last,we outlook the challenges and very important directions in key materials development.

Corrigendum to“Rearrangement on surface structures by boride to enhanced cycle stability for LiNi_(0.80)Co_(0.15)Al_(0.0)5O_(2) cathode in lithium ion batteries”[J.Energy.Chem.45(2020)110-118]

The authors regret that the printed version of the above article contained some errors.The funding number in acknowledgments of this paper was incorrectly marked,and we hope to correct it.We thank the National Natural Science Foundation of China(51764048,51703118 and 51474191),Yunnan Province Thousand Youth Talents Plan,the Application Basis Research Project of Yunnan Province Science and Technology Department(2017FD144)and Key Natural Science Foundation of Yunnan Province China(2018FA28)for providing the financial support.

Scalable synthesis of N-doped Si/G@voids@C with porous structures for high-performance anode of lithium-ion batteries

The co-utilization of silicon(Si) and graphite(G) has been considered as the preferred strategy to achieve high energy density anode materials,but the effective synergistic integration of Si and graphite is still a challenge and it is necessary to find a scheme to accommodate the large-scale production of Si/graphite anodes.In this work,silicon cutting waste from the photovoltaic industry was used as raw material,mixed with graphite,pitch,and polyvinylpyrrolidone,and subjected to high-energy ball milling.The mixture was then heated in an Ar atmosphere for the carbon coating,and the resulting Si/graphite/carbon(Si/G/C) composite was etched to remove the thicker SiOx layer formed on the Si surface to allow the pores between the Si and the carbon matrix to obtain Si@voids/G@C.Benefiting from the integrated structural design and the significantly enhanced electronic conductivity,the Si/G@voids@C composite exhibited the first dischargespecific capacity of 2530 mAh·g^(-1) with an initial coulombic efficiency(ICE) of 86.7%,and the remaining capacity exceeded 1000 mAh·g^(-1) after 550 cycles at 1.5A·g^(-1).Notably,full lithium-ion batteries with a Si/G@voids@C anode and LiFePO_4 cathode delivered a stable capacity of 140 mAh·g^(-1).The synthesis method is facile and cost-effective,providing an integration strategy for Si and G with a potential scheme for large-scale commercial applications.

A Photodetector based on ZnO Nanorods

In this work,a photodetector based on ZnO nanorods array was vertically grown on the nanoZnO film.ZnO nanorods playing two roles in the photodetector,as the materials of absorbing UV light and carrier transport path.We used the solgel method to prepare the ZnO seed solution and annealed to get nano-ZnO film.Then,ZnO nanorods array were fabricated by

A two-terminal all-inorganic perovskite/organic tandem solar cell

Organic-inorganic lead halide perovskite solar cells(PSCs)have been marching rapidly in recent years with power conversion efficiency(PCE)boosting from 3.8%to 24.2%(NREL Best Research-Cell Efficiency Chart,https://www.nrel.gov/pv/cell-effi ciency.html,Accessed April 2019).However,these solar cells are not stable at high temperatures due to volatile organic cations[1].Allinorganic perovskites with cesium cation like CsPbI1-xBrx present high thermal stabilities[2].By partially replacing I-with Br-,the bandgap for CsPbI1-xBrx can be tuned from 1.73 to 2.36 eV.

Synthesis of three-dimensionally ordered porous perovskite type LaMnO_3 for Al-air battery

LaMnO3 catalysts with three-dimensionally ordered holes perovskite structure were prepared via closepacked SiO2 template synthesized by Stober-Frink method. SEM, XRD and BET were employed to characterize the microstructure, phases and specific surface area. CV method was used to the oxygen electrode beha-vior of catalysts. Diameter of the holes was about 330 nm, corresponding to the size of SiO2 template. Full-cell discharge tests were performed on aluminum-air battery fabricated by porous LaMnO3.Results showed that the discharge performance of porous LaMnO3 were 1.54 V, 1.42 V and 1.24 V respectively when the discharge currents were set at 5 mA/cm^2,10 mA/cm^2 and 20 mA/cm^2, respectively, which were higher than that of LaMnO3 prepared by coprecipitation method（1.33 V, 1.09 V, 0.63 V, respectively）.

Trace detection of Ce^(3+) by adsorption strip voltammetry at a carbon paste electrode modified with ion imprinted polymers

To develop a convenient method for sensitive and selective determination of Ce3＋ in aqueous phase with complicated matrices, a carbon paste electrode（CPE） modified with ion imprinted polymers（IIPs） were fabricated. The polymers were prepared by precipitation polymerization using Ce3＋ as template, allyl phenoxyacetate（APA） as monomer, ethylene glycol dimethacrylate（EGDMA） as crosslinker and azobisisobutyronitrile（AIBN） as initiator under the molar ratio of Ce3＋, APA and EGDMA as 1：4：40, respectively. Ce3＋ was detected directly by differential pulse adsorptive stripping voltammetry（DPASV） and its oxidation peak appears at about 0.93 V. All parameters affecting the sensor＇s response are optimized and a calibration curve is plotted at a linear range of 1.0 × 10^（-6）-1.0 x 10^（-5） mol/L and 1.0×10^（-5）-2.0 × 10^（-4）mol/L with the detection limit of 1.5 × 10^（-7） mol/L. All other rare earth ions have no interference with the determination of Ce^（3＋） even at a concentration 500 times higher than that of Ce^（3＋）.This sensor was successfully applied to determination of Ce^（3＋） in two catalyst sample solutions with RSD≤3.3%（n = 5）and recoveries in the range of 99.2%-106.5% at our optimal conditions.

Synthesis of super-fine L1_(0)-FePt nanoparticles with high ordering degree by two-step sintering under high magnetic field

Super-fine L1_(0)-Fe Pt nanoparticles(NPs)with high ordering degree were successfully prepared by a modified two-step sintering method,which includes low-temperature pre-sintering,and the high magnetic field(HMF)assisted post-sintering processes.The particle size of the L1_(0)-FePt NPs was obviously refined by lowering the sintering temperature.By applying the HMF during the post-sintering process,the fine size characteristics of L1_(0)-Fe Pt NPs were retained,and the ordering degree was significantly improved.The L1_(0)-Fe Pt NPs with sizes of about 4.5 nm,ordering degree of 0.940,and coercivity of 22.01 k Oe were obtained by this two-step sintering under a magnetic field of 12 T.The mechanism investigation of HMF enhancing the ordering degree indicates that the HMF enhances lattice distortion and magnetization energy(Zeeman energy).The enhanced lattice distortions cause high stress existing in the lattice,which can effectively promote the disordered-order transition.When the magnetic field reaches to 3 T,the Zeeman energy of the NPs is higher than the thermal disturbing energy of the NPs,and the magnetization effect is stronger.Therefore,the HMF(higher than 3 T)can obviously improve the disorder-order transition by lowering the energy barrier and accelerating the orderly diffusions of atoms.The HMF is a promising assistant to synthesize the L1_(0)-phase NPs with both of high ordering degree and super-fine size.