CHEMISTRY-A EUROPEAN JOURNAL
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2017
·Vol. 24
·期 9
·2151-2156
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IF 5.317
Linna Sha,Peng Gao,Xiaochen Ren,Qianqian Chi,Yujin Chen,Piaoping Yang
Graphical Let it Se : An Se−C-bonded interface has been constructed in a Se–graphene (GE) composite through facile high-energy ball-milling. Due to the presence of Se−C bonds, a new self-repairing Se-GE cathode material has been obtained (see graphic). It shows high reversible capacity, long cycle life, and high coulombic efficiency. Lithium–selenium batteries, employing selenium as a cathode material, exhibit some notable advantages, such as high discharge rates and good cycling performance, due to their high electrical conductivity, high output voltages, and high volumetric capacity density. However, an important problem, termed the “shuttle effect”, can lead to capacity decay in Li-Se cells (and in Li-S cells), which arises from aggregation and the loss of Se or S from the cathode into the electrolyte. In this work, in order to solve this problem, a new self-repairing system has been devised, in which some Se atoms are chemically bonded to the carbon atoms of graphene and act as reclaiming points for dissociated Se atoms through the establishment of -Se-Se-Se- chains. Se-decorated graphene (Se-GE) was first constructed through a facile high-energy ball-milling process. Its formation was confirmed by XRD, SEM, HRTEM, XPS, and Raman analyses. As we anticipated, in examining cell properties, the as-prepared Se-GE composite underwent an initial capacity decay in the first 20 cycles (from 1050 mAh g −1 to 750 mAh g −1 , ca. 29 % loss), but the capacity then reverted to 970 mAh g −1 (ca. 92 % of the initial value). Other measurements were also consistent with the recapture of dissociated Se atoms.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
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2017
·
IF 6.216
Hai Huang,Changchang Ma,Zhi Zhu,Xin Yao,Yang Liu,Zhi Liu,Chunxiang Li,Yongsheng Yan
A novel multidimensional heterojunction, the 1D trigonal Se nanorods (t-Se NRs) dissociated from CdSe QDs germinating on the 2D BiOCl ultrathin nanosheets, was successfully synthesized via a facile hybridization method. Such unique nanocomposite served as an efficient visible-light-driven photocatalyst for the photodegradation of the tetracycline hydrochloride (TC-HCl) solution. The obviously enhanced photocatalytic performance compared with pure BiOCl was mainly attributed to the introduction of Se NRs, which greatly enhanced the optical absorption in visible-light region and suppressed the recombination rate of electron-hole pairs by steering the charges migrating in a special manner. Specially, t-Se NRs in BiOCl system played an integral and important role as holes transfer channels, impelling more photogenerated electrons of BiOCl to participate in the photocatalytic process. Reactive species trapping experiments indicated the main reactive species were O 2 – radicals, which were generated by the collisions of excited electrons and molecular oxygen. Meanwhile, the radically increased ESR peak of O 2 – radicals for the heterogenous materials demonstrated successful release of abundant high-energy electrons. This work could be extended to the design of other robust 1D/2D heterojunction photocatalysts in application to the environmental demands.
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ACS Applied Materials & Interfaces
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2018
·
IF 8.097
Jingling Li,Zheng Liang,Qiucheng Su,Hu Jin,Kelai Wang,Gang Xu,Xueqing Xu
For an organic–inorganic hybrid quantum dot light-emitting diode (QD-LED), enhancing hole injection into the emitter for charge balance is a priority to achieve efficient device performance. Aiming at this, we employ N,N′-bis(3-methylphenyl)-N,N′-bis(phenyl)benzidine (TPD) as the additional hole transport material which was mixed with poly(9-vinylcarbazole) (PVK) to form a composite hole transport layer (HTL) or was employed to construct a TPD/PVK bilayer structure. Enabled by this TPD modification, the green QD-LED (at a wavelength of 515 nm) exhibits a subband gap turn-on voltage of 2.3 V and a highest luminance up to 56 157 cd/m2. Meanwhile, such TPD modification is also beneficial to acquire efficient blue and red QD-LEDs. In particular, the external quantum efficiencies (EQEs) for these optimized full-color QD-LEDs are 8.62, 9.22, and 13.40%, which are 3–4 times higher than those of their pure PVK-based counterparts. Revealed by the electrochemical impedance spectroscopy, the improved electroluminescent efficiency is ascribable to the reductions of recombination resistance and charge-transfer resistance. The prepared QD-LEDs surpass the EQE values achieved in previous reports, considering devices with small-molecule-modified HTLs. This work offers a general but simple and very effective approach to realize the low turn-on-voltage, bright, and efficient full-color QD-LEDs via this solution-processable HTL modification.
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Nanomaterials
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2017
·Vol. 8
·期 1
·8
·
IF 3.553
Bing-Qian Zhang,Yu Liu,Yong Zuo,Jing-Shuai Chen,Ji-Ming Song,He-Lin Niu,Chang-Jie Mao
Copper-based chalcogenides that contain abundant, low-cost and environmentally-friendly elements, are excellent materials for numerous energy conversion applications, such as photocatalysis, photovoltaics, photoelectricity and thermoelectrics (TE). Here, we present a high-yield and upscalable colloidal synthesis route for the production of monodisperse ternary I-III-VI2chalcogenides nanocrystals (NCs), particularly stannite CuFeSe2, with uniform shape and narrow size distributions by using selenium powder as the anion precursor and CuCl2·2H2O and FeCl3as the cationic precursors. The composition, the state of valence, size and morphology of the CuFeSe2materials were examined by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), transmission electron microscope (TEM) and high resolution transmission electron microscope (HRTEM), respectively. Furthermore, the TE properties characterization of these dense nanomaterials compacted from monodisperse CuFeSe2NCs by hot press at 623 K were preliminarily studied after ligand removal by means of hydrazine and hexane solution. The TE performances of the sintered CuFeSe2pellets were characterized in the temperature range from room temperature to 653 K. Finally, the dimensionless TE figure of merit (ZT) of this Earth-abundant and intrinsicp-type CuFeSe2NCs is significantly increased to 0.22 at 653 K in this work, which is demonstrated to show a promising TE materialand makes it a possiblep-type candidate for medium-temperature TE applications.Keywords:CuFeSe2;nanocrystals;colloidal synthesis;ligand removal;thermoelectric property
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APPLIED SURFACE SCIENCE
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2018
·
IF 4.439
Xu Mao,Jianpeng Zou,Hongchao Li,Zhengqi Song,Siru He
Tungsten diselenide (WSe 2 ) films with different growing orientations exhibit diverse photoelectric properties. The WSe 2 film with C-axis⊥substrate texture has been prepared and applied to thin-film solar cells. W nanofilms with a thickness of 270 nm were deposited onto the Mo bottom electrode and then heat-treated in selenium vapor to synthesize WSe 2 films with a thickness of 1 μm. ZnO films were deposited onto WSe 2 films to form a P-N junction and ITO films were deposited subsequently as the conductive layer. X-ray diffractometry, scanning electron microscopy and UV-vis-NIR spectro-analysis instrument were employed to analyze the phase composition, optical absorptivity and micromorphology of WSe 2 films and the WSe 2 solar cell device. WSe 2 films exhibit excellent photoelectric performance with an optical absorption coefficient greater than 10 5 cm −1 across the visible spectrum. The calculated direct and indirect band gap of the WSe 2 films is 1.48 eV and 1.25 eV, respectively. With the application of standard glass/Mo/WSe 2 /ZnO/ITO/Ag device structure, the open-circuit voltage of the battery device is 82 mV. The short-circuit current density is 2.98 mA/cm 2 and the filling factor is 0.32. The photoelectric conversion efficiency of the WSe 2 film solar cell device is 0.79%.
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CRYSTENGCOMM
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2018
·Vol. 20
·期 18
·2519-2527
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IF 3.304
Chi Zhang,Xiaoming Fu,Zhiwei Peng,Junhui Gao,Yong Xia,Jianbing Zhang,Wei Luo,Honglang Li,YuHuang Wang,Daoli Zhang
Compared to binary PbSe or PbS nanocrystals (NCs), ternary PbSe1−xSx alloyed NCs have unique electronic and optical properties such as high quantum efficiency, narrow band edge, and fast response time, and are widely used in infrared optoelectronic devices. In this work, high-quality composition-tunable monodisperse ternary PbSe1−xSx alloyed NCs were synthesized by employing cation exchange from host CdSe1−xSx alloyed NCs, which were pre-fabricated by using cadmium oxide, myristic acid and 1-octadecene (ODE) solutions of selenium/sulphur powders (Se/S-ODE), excluding toxic phosphine-containing solvents. The alloyed nature of PbSe1−xSx NCs was confirmed using powder X-ray diffraction (XRD). XRD patterns and field emission transmission electron microscopy (FETEM) images demonstrated that the average diameters of the resulting PbSe1−xSx alloyed NCs were not more than 5 nm, and ultraviolet-visible-near infrared (UV-vis-NIR) absorption spectra indicated that the NC size, hence the band gap, bared a linear relationship with the first absorption peak position. The temporal evolution of the absorption spectra revealed that the PbSe1−xSx alloyed NCs were air-stable due to the hybrid surface passivation of Cl− and Cd2+. X-ray fluorescence results indicated that slight stoichiometric deviations of PbSe1−xSx NCs occurred but never exceeded 15% of the expected composition, based on the amount of introduced hosts.
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Soft Matter
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2017
·Vol. 14
·期 6
·921-926
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IF 3.889
Tongbing Sun,Caizhen Zhu,Jian Xu
Novel biodegradable diselenide cross-linked starch-based hydrogels were synthesized via free radical copolymerization, which serve as stimuli-responsive drug release materials composed of starch chain backbones with an enzyme hydrolysis property and selenium-containing cross-linkers with a redox responsive cleavage property. Rhodamine B (RB) loaded starch-based hydrogels were prepared in order to investigate their stimuli-responsive release behaviours. In the presence of external redox agents, the enzyme stimuli as well as the mixture of the above stimuli, the prepared starch-based hydrogels exhibit controlled multi-responsive release behavior of RB. Overall, the merits of good biodegradation and multi-stimuli responsiveness make these kinds of starch-based hydrogels promising biomedical candidates for the realization of controlled drug delivery.
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Advanced Optical Materials
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2018
·Vol. 6
·期 10
·1701389
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IF 7.43
Zhongyuan Guan,Aiwei Tang,Peiwen Lv,Zhenyang Liu,Xu Li,Zhan'ao Tan,Tasawar Hayat,Ahmed Alsaedi,Chunhe Yang,Feng Teng
A series of multinary Cu-In-Zn-Se-S nanocrystals (NCs) are synthesized via a phosphine-free and one-pot approach, in which the Se powder and 1-dodecanethiol (DDT) are used as chalcogenide sources, respectively. The X-ray photoelectron spectra are used to confirm the presence of lattice sulfur in the as-obtained products. The emission color and the relative photoluminescence quantum yields of the Cu-In-Zn-Se-S NCs can be tuned by varying the Cu contents, the amount of Se powder, as well as the DDT dosage. In addition, the formation process of the multinary Cu-In-Zn-Se-S NCs is different from that of quaternary Cu-In-Zn-S NCs, which is dominated by the doping of Cu ions into the In-deficient In-Zn-Se-S NCs but not the partial interdiffusion of Zn 2+ into the Cu-based NCs. This plausible deduction is based on the comparison of optical properties of the products synthesized using the hot-injection and one-pot methods. Furthermore, the performance of the solution-processed quantum-dot light-emitting diodes (QLEDs) using the Cu-In-Zn-Se-S NCs as emission layers is examined, and the QLEDs exhibit a high luminance over 1500 cd m −2 and a high peak current efficiency of ≈0.4 cd A −1 at 1000 cd m −2 .
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Journal of Materials Chemistry C
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2018
·Vol. 6
·期 10
·2573-2579
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IF 5.976
Ruiqi Guo,Ting Shen,Jianjun Tian
“Green” narrow band-gap CuInSe2 quantum dots (QDs) were first introduced in photodetectors. Thus, a broadband hybrid photodetector was obtained by combining the ultraviolet detection of spiro-OMeTAD and the near-infrared detection of CuInSe2 QDs. In order to improve the detection of the device, the oil-soluble CuInSe2 QDs were transformed into water-soluble MPA-capped QDs through ligand exchange, which drastically shortened the length of the surface ligand. The specific detectivity (D*) of the photodetector reached 1.6 × 1012 Jones at 330 nm and 7.5 × 1010 Jones at a 1000 nm wavelength. The unencapsulated device also displayed a fast response time (<0.02 s) and excellent thermal stability (20–100 °C) in ambient air. This work could open a window of toxic-free QD based photodetectors to achieve a broadband response.
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JOURNAL OF APPLIED POLYMER SCIENCE
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2018
·Vol. 135
·期 22
·46326
·
IF 1.901
Weining Du,Yong Jin,Jiezhou Pan,Wuhou Fan,Shuangquan Lai,Xiaopeng Sun
Herein, we synthesized a series of polyurethane copolymers (PUs) with poly(1,4-butylene adipate) glycol as soft segment and 2,4-toluene diisocyanate as well as extenders including 1,4-butanediol and di(1-hydroxyethylene) diselenide as hard segment. The chemical structure, thermal property, crystallization behavior, shape memory, and self-healing performances of the PUs were systematically characterized by a series of experiments. It was found that the PU2 containing a higher diselenide component (∼33 mol %) exhibited both shape memory and self-healing behaviors under a moderate temperature (∼57 °C). Meanwhile, the PUs showed a good repeatability of shape memory function, and their fixity and recovery ratios were all above 90%. Additionally, the dynamic exchangeable feature of diselenide bonding endues the PUs chains with an acceptable reprocessability and self-healing performances, and the PU2 sample could be healed for five times by thermal treatment with the healing efficiencies above 70%. This work provides a heuristic perspective for the development of shape memory and self-healing materials. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 46326.
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ACS Nano
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2018
·
IF 13.709
Hongli Wan,Jean Pierre Mwizerwa,Xingguo Qi,Xin Liu,Xiaoxiong Xu,Hong Li,Yong-Sheng Hu,Xiayin Yao
High ionic conductivity electrolyte and intimate interfacial contact are crucial factors to realize high-performance all-solid-state sodium batteries. Na2.9PS3.95Se0.05 electrolyte with reduced particle size of 500 nm is first synthesized by a simple liquid-phase method and exhibits a high ionic conductivity of 1.21 × 10–4 S cm–1, which is comparable with that synthesized with a solid-state reaction. Meanwhile, a general interfacial architecture, that is, Na2.9PS3.95Se0.05 electrolyte uniformly anchored on Fe1–xS nanorods, is designed and successfully prepared by an in situ liquid-phase coating approach, forming core–shell structured Fe1–xS@Na2.9PS3.95Se0.05 nanorods and thus realizing an intimate contact interface. The Fe1–xS@Na2.9PS3.95Se0.05/Na2.9PS3.95Se0.05/Na all-solid-state sodium battery demonstrates high specific capacity and excellent rate capability at room temperature, showing reversible discharge capacities of 899.2, 795.5, 655.1, 437.9, and 300.4 mAh g–1 at current densities of 20, 50, 100, 150, and 200 mA g–1, respectively. The obtained all-solid-state sodium batteries show very high energy and power densities up to 910.6 Wh kg–1 and 201.6 W kg–1 based on the mass of Fe1–xS at current densities of 20 and 200 mA g–1, respectively. Moreover, the reaction mechanism of Fe1–xS is confirmed by means of ex situ X-ray diffraction techniques, showing that partially reversible reaction occurs in the Fe1–xS electrode after the second cycle, which gives the obtained all-solid-state sodium battery an exceptional cycling stability, exhibiting a high capacity of 494.3 mAh g–1 after cycling at 100 mA g–1 for 100 cycles. This contribution provides a strategy for designing high-performance room temperature all-solid-state sodium battery.
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ACS Applied Energy Materials
·
2018
·
IF 0
Junjie Fu,Jie Fu,Qingwen Tian,Houlin Wang,Fengming Zhao,Jun Kong,Xiangyun Zhao,Sixin Wu
The Se content in a Cu2ZnSn(S, Se)4 absorber layer has a significant impact on the electronic properties, but it is rather challenging to control the Se/(S + Se) ratio due to a complicated selenization process. Here, a low-toxicity thiol/amine-based solution process was developed to tune the Se content in a Cu2ZnSn(S, Se)4 absorber layer to an optimal value by ingeniously controlling the SeO2 in the precursor solution. We demonstrated that the crystal growth and the band gap of Cu2ZnSn(S, Se)4 thin films are affected by the Se/(S + Se) ratio. By this approach, the open-circuit voltage deficit (Voc,def) of the device was effectively decreased, and the short-circuit density (Jsc) and fill factor (FF) were remarkably improved; thus, the power conversion efficiency of the Cu2ZnSn(S, Se)4 solar cells was successfully increased from 5.6% to 9.7% for the optimal band gap (Eg = 1.13 eV).
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