查找使用阿拉丁产品的科研文献

Colloidal Synthesis of Giant Shell PbSe-Based Core/Shell Quantum Dots in Polar Solvent: Cation Exchange versus Epitaxial Growth

Dong Li,Xiaoli Zhang,Muhammad Ramzan,Kai Gu,Yu Chen,Jiatao Zhang,Bingsuo Zou,Haizheng Zhong

Shell thickness control of core/shell quantum dots (QDs) plays an important role in determining their optical properties as well as the corresponding device performance. PbSe-based core/shell QDs are attractive near-infrared (NIR) light emitters for photonic and optoelectronic applications. We herein report the colloidal synthesis of giant shell PbSe-based core/shell QDs through controllable reactions between preformed PbSe QDs and Cd2+ ions in polar solvents. The preformed PbSe QDs experienced cation-exchange reaction in N,N-dimethylformamide (DMF), while they underwent epitaxial growth of CdS shell in dimethyl sulfoxide (DMSO). The cation exchange of preformed PbSe QDs in DMF result in PbSe/CdSe core/shell QDs with similar size (ca. 6.3 nm) but tunable shell thickness from 0.5 to 2.9 nm. In comparison, the epitaxial growth of preformed PbSe QDs in DMSO produce PbSe/CdS core/shell QDs in DMSO with average core size of ∼5.7 nm but tunable shell thickness from 0.5 to 3.1 nm. These resulting PbSe-based core/shell QDs show tunable photoluminescence emission of 1393–1744 nm for PbSe/CdSe core/shell QDs and 1566–1719 nm for PbSe/CdS core/shell QDs. The cation exchange and epitaxial growth reactions of preformed PbSe QDs were further investigated by comparing the interactions between solvents and cation ions through nuclear magnetic resonance (NMR) measurements. The interactions between Cd2+ and DMSO are stronger than that of DMF, while the interactions between Pb2+ and DMSO are weaker than that of DMF. The difference accounts for the reaction transition from cation exchange to epitaxial growth, providing alternative route for fabricating shell controllable PbSe-based core/shell QDs.

Enhanced optical anisotropy via dimensional control in alkali-metal chalcogenides

Jingmei Min,Ailijiang Abudurusuli,Junjie Li,Shilie Pan,Zhihua Yang

Crystals with both large birefringence and wide transparent range are suitable for broad applications in the areas of optical communications, the laser industry and modulation of the light polarization requirement. In this work, to assist the design of urgently needed crystals with large birefringence in the infrared (IR) region, typical alkali-metal chalcogenides, KPSe6, Na2Ge2Se5, and Li2In2GeSe6 have been studied. They exhibit a hierarchical characteristic in the calculated birefringence by about 0.21, 0.11, and 0.04, respectively. To explore the origin of the birefringence difference, the polarizability anisotropy and the effect of electron distribution anisotropy are analyzed. The alkali-metal chalcogenides KPSe6, Na2Ge2Se5, and Li2In2GeSe6 feature infinite one-dimensional (1D) chains of [PSe6], 2D anionic framework of [Ge2Se5] layers and 3D [In2GeSe9] networks, respectively. It is found that the anionic group with low-dimensional configuration could enhance polarizability anisotropy and render large birefringence for the macroscopic structure. This provides evidence that a low-dimensionality configuration in the structure would be beneficial for the enhancement of optical anisotropy, which can motivate the exploration and design of novel IR birefringent materials.

Mixing solvothermal synthesis nickel selenide on the surface of graphene for high-efficiency asymmetric supercapacitors

Shang Wu,Tao Cui,Qinzheng Hu,Fenping Yin,Qiaoliang Feng,Sheng Zhou,Qiong Su,Lan Wu,Quanlu Yang

Nickel selenide nanoparticles uniformly supported on graphene nanosheets to form NiSe 2 /rGO composites were prepared via one-step mixing solvothermal method. The NiSe 2 /rGO composite possesses a high specific capacity of 137.7 mA h g −1 (1A g −1 ) and displays an excellent rate property. Moreover, there are NiSe 2 /rGO-20 as electrode materials assembling asymmetric supercapacitors, which manifests high energy density (33.13 Wh kg −1 ) at a power density (850 W kg −1 ) and the capacity can maintain of 80 % after 10,000 cycles. Therefore, NiSe 2 /rGO composite can be a potential candidate for high-efficiency asymmetric supercapacitors.

Structure-controlled SnSe2 nanosheets as high performance anode material for lithium ion batteries

Cheng Yayi,Huang Jianfeng,Cao Liyun,Xie Hui,Wang Yongfeng,Wang Yanlong,Wu Hongqiang,Xi Shaohua,Li Jiayin

SnSe 2 is regarded as one of the promising anode materials for the advanced lithium ion batteries (LIBs) due to its high theoretical capacity and good conductivity. In this work, SnSe 2 with controllable structure is synthesized by a facile solvothermal method and the influence of reductant on the morphology is revealed. It is found that interconnected SnSe 2 nanosheet assembled by ultrafine nanoparticles exhibits excellent electrochemical performance. As LIBs anode material, the SnSe 2 nanosheet delivers a high initial reversible capacity of 932 mAh g −1 with the coulombic efficiency of 75.2% at 200 mA g −1 , remaining at 334 mAh g −1 over 200 cycles. This highly reversible capacity and cycling stability are mainly ascribed to its special interconnected thin nanosheets structure, which could provide a three-dimensional network paths for ultrafast charge transfer.

Hexagonal SnSe nanoplate supported SnO2-CNTs nanoarchitecture for enhanced photocatalytic degradation under visible light driven

Marimuthu Karpuraranjith,Yuanfu Chen,Xinqiang Wang,Bo Yu,Sivamoorthy Rajaboopathi,Dongxu Yang

It is still challengeable to develop low-cost metal-based photocatalysts with high efficiency and stability for organic pollutant degradation. Herein, we propose a novel “interfacial engineering and suitable band gap matching” strategy to synthesize hexagonal SnSe nanoplate supported SnO 2 -CNTs for highly efficient photocatalytic activity. The CNTs-SnO 2 /SnSe, constructed by SnO 2 nanoparticles homogeneously embedded in carbon nanotube surface, which is anchored on hexagonally crystalline SnSe nanoplates, is synthesized by a facile low-cost and eco-friendly one-pot solvothermal reaction. Compared to SnO 2 , SnSe, CNTs-SnO 2, SnO 2 /SnSe, the CNTs-SnO 2 /SnSe delivers significant performance, enhancement in photocatalytic degradation for aqueous organic dye pollutant under visible light irradiation in 60 min. The k value of CNTs-SnO 2 /SnSe is over 2.2 times larger than CNTs-SnO 2 , SnO 2 and SnSe. The remarkably enhanced photodegradation performance of CNTs-SnO 2 /SnSe is mainly attributed to its unique nanoarchitecture, high surface area and band gap matching: the CNTs skeleton can facilitate the electron transfer; band gap diagram of CNTs-SnO 2 /SnSe is beneficial to efficient electron-hole charge separation and recombination of electron-hole pair can be effectively suppressed. This work presents a rational catalyst design with nanoarchitecture and band gap matching, and a facile one-pot synthesis strategy to synthesize low-cost photocatalysts for dye pollutant degradation with prominent high-efficiency and long-term stability.

Production, removal and fate of steroid estrogens under the background of total sewage interception in the Erhai Lake Basin, China

Jian Shen,Xueying Li,Xinze Wang,Jimeng Feng,Shiyi Jiang,Zhiping Zhang,Qian Xu

The Erhai Lake basin dominated by agricultural production had a total sewage interception system and was selected as the study area. Survey data showed the total steroid estrogens (SEs) production was 55.97 kg/year (EEQ-E2β) in the whole basin and the main source of SEs was swine breeding (57%). The results indicated that unsatisfactory removal effect of SEs could be related to insufficient influent carbon sources as a result of the total sewage collection. The observed average concentrations of E1, E2α, E2β, E3 and EE2 in rivers/ditches were 25.9 ng/L, 43.5 ng/L, 14.4 ng/L, 49.4 ng/L and 24.5 ng/L, and SEs in ditches were significantly higher than that in rivers, proving the influence of the irrigation tailwater. Above, the annual SEs contribution for Erhai Lake was estimated, and the correlation coefficient of SEs and water quality of inflow rivers/ditches indicated that SEs had a certain correlation with nitrogen.

Facile in situ solution synthesis of SnSe/rGO nanocomposites with enhanced thermoelectric performance

Lisi Huang,Jianzhang Lu,Duowen Ma,Chunmiao Ma,Bin Zhang,Hengyang Wang,Guoyu Wang,Duncan H. Gregory,Xiaoyuan Zhou,Guang Han

Constructing nanostructured composite architectures has been considered as an effective strategy to reduce the lattice thermal conductivity (κL) and enhance the dimensionless figure of merit (ZT) of thermoelectric materials. Herein, a series of SnSe/reduced graphene oxide (rGO)-x (x = 0.1, 0.3, 0.5, 0.7 wt%) nanocomposites are controllably synthesised in situ via a facile single-step bottom-up solution method, where rGO nanosheets are incorporated intimately into the SnSe matrix. Nanocompositing performs two key functions: (i) significantly reducing the lattice thermal conductivity of the material, which can be attributed to enhanced phonon scattering from high-density SnSe/rGO interfaces, and (ii) improving the electrical conductivity over the low temperature range, as result of an increased carrier concentration. The subsequent thermoelectric performance of SnSe/rGO sintered pellets has been optimised by tuning the rGO mass fraction, with SnSe/rGO-0.3 achieving κL = 0.36 W m−1 K−1 at 773 K (cutting the κL of SnSe by 33%) to yield a maximum ZT of 0.91 at 823 K (representing a ∼47% increase compared to SnSe). This study provides a new pathway to improve the thermoelectric performance of polycrystalline SnSe by way of engineering metal chalcogenide/rGO composite architectures at the nanoscale.

Highly Polarized Active Fluorescent Enhancement Polymer Film With Quantum Rods Aligned by Ink-Jet Printing

Ziming Zhou,Haochen Liu,Wenda Zhang,Zuoliang Wen,Junjie Hao,Bing Xu,Kai Wang,Kie-Leong Teo,Xiao-Wei Sun

Se molarity tuned composition and configuration of Ni3Se2/NiSe core-shell nanowire heterostructures for hydrogen evolution reaction

Hong-Bo Wang,Yang-Shuo Sun,Fei Ma,Liang Zhou,Hui-Feng Li,Long Zhang,Guan-Jun Chen,Yi-Ku Xu,Yong-Nan Chen,Ke-Wei Xu,Da-Yan Ma

Well-arranged heterogeneous interface is favored to enhance the electrocatalytic activities to utilize the synergistic effects of different crystalline phases. In this work, vertical aligned single crystal Ni 3 Se 2 nanowires (NWs) wrapped by ultra-thin NiSe nanoflakes (NFs) with well-arranged heterogeneous interfaces along axial direction were successfully in situ grown on nickel foam (Ni foam) by a simple one-step hydrothermal method without posttreatment. The growth of Ni 3 Se 2 NWs follows a surface reaction mechanism by which NiSe reacts with reactive Ni · atoms on surface lattice steps of Ni 3 Se 2 nucleuses to grow both along radial and axial directions. The configurations of the products can be tuned from NiSe NFs to the core-shell NWs dominated structures by solely modulating Se molarity in chemical precursors motivated by the accelerated reaction kinetics. The hydrogen evolution reaction (HER) performance was improved with the increase of Se molarity attributing to the increased coverage of high aspect Ni 3 Se 2 /NiSe core-shell NWs arrays, metallic conductive feature of Ni 3 Se 2 skeleton and well-arranged heterogeneous interfaces along the axial direction. The Ni 3 Se 2 /NiSe core-shell NWs with well-arranged heterogeneous interfaces may also be beneficial to other energy or environmental applications.

Plasmonic Au nanoparticle-decorated Bi2Se3 nanoflowers with outstanding electrocatalytic performance for hydrogen evolution

Dong Li,Jie Lao,Chunli Jiang,Chunhua Luo,Ruijuan Qi,Hechun Lin,Rong Huang,Geoffrey I.N. Waterhouse,Hui Peng

Hydrogen production from water splitting through electrocatalytic or photoelectrochemical route shows great potential for renewable energy conversion. Herein, the plasmon-enhanced photoelectrical nanocatalysts (NCs) have been successfully developed by Au nanoparticle-decorated Bi 2 Se 3 nanoflowers (Au@Bi 2 Se 3 NFs) as catalysts for hydrogen evolution reaction (HER), leading to a more than 3-fold increase of current under excitation of Au localized surface plasmon resonance (LSPR) and affording a markedly decreased overpotential of 375 mV at a current density of 10 mA cm −2 . The HER enhancement can be largely attributed to effective electron-charge separation and the increase of carrier density in Bi 2 Se 3 induced by the injection of hot electrons of Au nanoparticles. Meanwhile, Bi 2 Se 3 nanoflowers (NFs), a kind of topological insulators, possess gapless edges on boundary and show metallic character on surface, providing a path for the flow of electrons in the electrocatalytic system . This study opens up a new avenue towards the design of higher energy conversion catalytic water splitting systems with the assistance of light energy , which could increase of HER catalysis efficiency by plasmonic excitation.

Heterovalent Ga3+ doping in solution-processed Cu2ZnSn(S,Se)4 solar cells for better optoelectronic performance

Yachao Du,Qingwen Tian,Jin Huang,Yuechao Zhao,Xiaohuan Chang,Afei Zhang,Sixin Wu

Additional elements in Cu2ZnSn(S,Se)4 (CZTSSe) absorber layers present a viable strategy to improve the performance of thin film solar cells. In this study, heterovalent cation doping by partially substituting metal cations with Ga3+ is explored by constructing a sandwich-like configuration. We demonstrated that a low doping level of Ga3+ can be successfully incorporated into the host lattice of CZTSSe to form a homogeneous Cu2ZnSn(Ga) (S,Se)4 (CZTGSSe) alloy material. Characterization was performed using SEM, EDS, XRD, Raman spectroscopy, and XPS, which showed that the material fabricated by this heterovalent cation doping method expressed high phase purity, appropriate valence components, and suitable optical bandgap, which are vital for high performance solar cells. As a result, the champion device achieves stabilized efficiency as high as 10.80%, improved by nearly 28% compared with only 8.43% for the reference device.

Hierarchical Cobalt Selenides as Highly Efficient Microwave Absorbers with Tunable Frequency Response

Min Zeng,Qian Cao,Jue Liu,Baiyu Guo,Xiaozhu Hao,Qingwei Liu,Xiaofang Liu,Xin Sun,Xixiang Zhang,Ronghai Yu

Microwave absorbing materials have attracted much attention in solving electromagnetic interference and pollution problems. Hierarchical cobalt selenides have been obtained through a facile selenization annealing process. The as-prepared samples exhibit distinct reflection losses (RL) and frequency responses via tailoring their crystalline configurations, with excellent absorption in Ku, X, or C band. All of the samples show RL greater than or near −50 dB with effective bandwidths more than 4 GHz, indicating that they may serve as high-efficient and frequency-tunable microwave absorbers. Especially, the sample annealed at 400 °C shows a competitive RL of −62.04 dB at 9.92 GHz with a thickness of 2.25 mm; meanwhile, its effective absorption bandwidth reaches 5.36 GHz with a thickness as small as 1.56 mm. The cobalt selenides as microwave absorbers exhibit a promising prospect applied in complex electromagnetic environments.