PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2020
·Vol. 22
·期 17
·9362-9367
·
IF 3.43
Weifeng Huang,Yingcai Zhu,Yong Liu,Lijuan Liu,Changchun Yang,Wei Xu
The quaternary chalcogenides consisting of earth-abundant elements such as Cu2ZnSnSe4 (CZTSe) have promising electrical and optical properties prompting enormous technological interest. Understanding different types of defects including Cu/Zn ordering is believed to be the key point to tackle technological challenges such as a large open circuit voltage deficit in CZTSe. The Te doped Cu2.2Zn0.8SnSe4−xTex (x = 0.01–0.04) were investigated using X-ray absorption fine structure spectroscopy at the Cu, Zn, and Se K-edges as well as at the Te L3-edge. Cu at the zinc site with anti-site defects and oxygen interstitials are identified. The detailed electronic structure upon Te doping is studied, providing insights into the rich defect chemistry present in this compound.
研究领域:
材料科学
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凝聚态物理
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无机化学
·
半导体材料
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光电功能材料
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Haoran Su,Xinyi Li,Dongze Li,Di Gao,Mengxue Zhang,Yufan Shang,Yanping Liu,Huiling Geng,Xiang Liu,Ruijin Yu
Thermal stability holds particular significance for phosphors intended for LEDs . Abnormal thermal quenching was successfully reached by strategic point defect engineering by inserting Frenkel defects and nonequivalent substitution defects in novel Sm 3+ ions doped Na-rich distorted double perovskite Na 1.5 La 1.5 TeO 6 phosphors. Its integral intensity at 420 K (115.03 %) was far higher than that of room temperature . Besides, the phosphors exhibited a pronounced orange-red emission peak at 644 nm when excited at 404 nm, which was ascribed to the 4 G 5/2 - 6 H 9/2 transition of Sm 3+ ions. The concentration quenching phenomenon resulting from dipole-dipole interactions was observed in the phosphors, and the optimal concentration of dopant Sm 3+ was determined to be 1 mol%. After calculation, it was surprising that the color purity values of all phosphors were not less than 99.9 %. Additionally, the internal quantum efficiency (IQE) reached 65.30 %, and the activation energy ( E a ) of Na 1.5 La 1.5 TeO 6 :1 mol%Sm 3+ was 0.570 eV. Meanwhile, the emission spectrum of the produced orange-red light emitting diodes (LEDs) exhibited a close correspondence with the absorption curves of various plant pigments (chlorophyll b , allophycocyanin, phycocyanin, phytochrome red and far red (P R and P FR )). The prepared white light emitting diodes (WLEDs) possessed low correlated color temperature (CCT) of 4769 K and as high general color rendering index (CRI, R a ) value as 91. In summary, the phosphors presented promising options for plant-cultivating LEDs and high CRI WLEDs based on their superior optical and thermal properties .
研究领域:
材料科学
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光学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2022
·
IF 14.224
Yanei Xue,Penghui Shao,Mingli Lin,Yixing Yuan,Wenxin Shi,Fuyi Cui
Defect engineering is crucial in the development of semiconductor catalyst activity. However, the influence of defect/vacancy density and states on catalysis remains vague. Thus, the optimized sulfur vacancy (S V ) state is achieved among Fe-ZnS models (ZFS) via a chemical etching strategy for photocatalytic degradation (PD). As the S V concentration (ρS V ) increases, the predominant state of vacancies changes from isolated defects－ a state to a combination of a state and vacancy clusters－ e state, as verified by positron annihilation and X-ray absorption fine structure spectra. However, the two types of defect states activated the intrinsic activity of the crystal via radically different mechanisms and exerted different degrees of influence on PD activity, as revealed by first-principles calculations and quantitative structure-activity relationship. Our results suggest that the S V activity is strongly influenced by its concentration in the ZFS crystal, while the vacancy concentration is not a control parameter for the PD activity, but a defect form. The underlying essence of atomic defects behavior affecting crystal catalytic activity at the atomic level is also revealed in this paper. Uncovering these structural relationships provide a theoretical basis for designing effective catalysts.
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Lei Wang,Xuan Liu,Mengting Huang,Yun Han,Panjie Guo,Run Huang,Ying Chen,Helong Wu,Jinyan Zhang,Shuangming Chen,Aijun Du,Xin Wang
Seawater electrocatalysis is highly desired for various energy storage and conversion systems, such as water splitting using seawater as an electrolyte and metal fuel cells. However, the adsorption of chloride ions (Cl–) on the active sites of cathodes would worsen the oxygen reduction reaction (ORR) activity and stability, thus lowering the battery performance. Herein, the coupling active sites of graphitic N-regulated adjacent pentagon defects in carbon nanosheets (GAP/CN) were first synthesized by a low-boiling-point metal-mediated partial N-removal strategy. Experimental and theoretical results affirm the advantageous cooperative effect between adjacent pentagons and graphitic N toward the ORR in a harsh seawater environment, where adjacent pentagons act as the authentic highly effective ORR active sites and surrounding graphitic N site serves as the structural regulator to weaken the binding strength of harmful Cl– to prevent catalyst poisoning. As a result, GAP/CN delivers excellent ORR activities in diverse electrolytes, including 0.1 M KOH (half-wave potential of 0.87 V), alkaline artificial seawater (half-wave potential of 0.87 V), and natural seawater (half-wave potential of 0.71 V), and also good long-term stability, which can be comparable to commercial Pt/C. This study provides valuable guidance for the rational design of ORR electrocatalysts for seawater-related energy-conversion devices.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2024
·
IF 18.5
Jianning Liu,Dongyan Zhang,Yangxi Yan,Zhimin Li,Fei Li,Sen Yang
Acceptor doping is a common method for hardening modified piezoelectric ceramics. The mechanism through which the hardening effect can be improved has been widely studied and verified. However, the effect of defects caused by different valence states of the B-site ions on the properties of multicomponent piezoelectric ceramics remains to be discussed. Therefore, in this work, a novel Pb(Ni 1/3 Nb 2/3 )O 3 –Pb(In 1/2 Nb 1/2 )O 3 –Pb(Mn 1/3 Nb 1/2 )–PbTiO 3 quaternary hard ceramic with excellent performance is prepared and studied. The interaction between grain-boundary defects and defect dipoles is proposed to be the mechanism behind the observed excellent performance. It is found that different types of defects improve the hardening effect in various ways. These results can provide a theoretical basis for the preparation of multicomponent piezoelectric ceramics with better properties.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
Nano Energy
·
2024
·
IF 16.8
Xinpeng Luan,Jianbo Li,Shipeng Wu,Guibin Zhang,Hexige Wuliji,Jun Wang
AgCuTe, a p-type medium-temperature thermoelectric material, exhibits great potential as a candidate for converting waste heat into electricity owing to its low thermal conductivity and high thermoelectric performance. However, an unstable phase structure of the material system has hindered the direct observation of various point defects contacting with high performance, despite their predicted possibilities solely based on first-principles calculations. Here, we present the novel observation of Te interstitial atoms together with other point defects, planar defects, and nanoscale atomic aggregation for the first time in the Zn-doped and Te non-stoichiometric AgCuTe system, employing a nanoscale perspective. Through our investigation, we disclose the remarkable coexistence of multidimensional defects, thereby resolving the previously conflicting opinions regarding point defects in this system. The effective control of these defects is crucial for achieving high thermoelectric performance. The Zn Cu point defects regulate carrier concentration and Seebeck coefficient by influencing phase proportion and carrier effective mass. While maintaining the material's inherently large power factor ( PF ), thermal conductivity is effectively reduced through grain refinement and multiscale defect scattering. As a result, the dimensionless thermoelectric figure of merit ( ZT ) of approximately ∼ 1.16 is achieved at 773 K. By altering Te content, a coexistence of diverse defects is introduced, leading to intricate microstructures and phase structures. Consequently, a significant reduction in thermal conductivity is observed. The coexistence of multidimensional defects, as well as their impact on microstructure and thermoelectric transport properties, holds significant implications for the performance control of functional materials.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Water Process Engineering
·
2024
·
IF 6.3
Liang He,Yanfei Liu,Huajing Zhou,Sheng Liang,Xiaolong Zhang,Zuwen Li,Zilian Liu,Rongrong Miao,Qingqing Guan
Targeted tuning of defect density in carbon-based photocatalysts is a key strategy to improve their photocatalytic performance. However, the current methods for intrinsic carbon defect sites construction are commonly with harsh conditions and costly materials, it is significant to develop more greener and cost-effective methods. In addition, the structure-activity relationship between the structural defects of material and photocatalytic performance was ambiguous up to now. Herein, a K + -assisted synthetic strategy was developed to synthesize porous carbon-based geopolymer micros (rpsBC-GPs 2 ) with abundant intrinsic defects using papermaking sludge as the precursor. And a mechanistic insight was given for explaining why the K + -induced defect density tuning made rpsBC-GPs 2 exhibit high photocatalytic activity . The introduction of K + changed the crystal structure of Quartz, calcite and pyrrhotite on the catalyst surface and promote the generation of lattice defects . The abundant lattice defects and sp 3 carbon defects of rpsBC-GPs 2 were evidenced with X-ray Photoelectron Spectroscopy, X-ray Diffraction, and scanning transmission electron microscopy measurements. In the photocatalytic process, the photogenerated electrons was driven to capture dissolved oxygen and form ·O 2, because the conduction position of rpsBC-GPs 2 was higher than the potential of O 2 /O 2 − (−0.33 eV). In addition, the high-conductive biochar play a role of “electron shuttle” in the photocatalytic process, which promoted the electrons transfer from CB to O 2 . Therefore, the production efficiency of reactive ·O 2 − was improved, and promoted the aromatization reaction process of tetracycline (TC). In this study, an industrial waste paper sludge was utilized to synthesize the active photocatalyst, and a new strategy was proposed for the photocatalytic performance evaluation, through targeted tuning of defect density in carbon-based photocatalysts using K + as activator.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Zanyu Chen,Jiugang Hu,Shijun Liu,Hongshuai Hou,Guoqiang Zou,Wentao Deng,Xiaobo Ji
Vanadium oxides are considered as promising cathode materials for aqueous zinc ions batteries (AZIBs). However, the long diffusion distance, low diffusion coefficient, and strong electrostatic interactions with divalent Zn 2+ in bulk vanadium oxide restrict their practical application. In this work, vanadium oxide nanofibers with physical and chemical defects were facilely fabricated by electrospinning for the application in AZIBs. The hierarchical framework exhibits structure stability during insertion/ extraction processes of zinc ions, and the extracted zinc ions are easily confined in the caverns of porous fibers to shorten the diffusion paths. Furthermore, the electrochemical reaction mechanism was verified by using in situ Raman and ex situ XPS and HRTEM, demonstrating a co-insertion mechanism of zinc ions and H + . The cathode shows a fast activation process, exhibiting a high capacity of 256 mAh g −1 at 1 A g −1 , and the capacity fading of only 17% is observed after 1000 cycles at 5 A g −1 . The outstanding electrochemical performances and efficient Zn 2+ transportation can be attributed to the synergism of physical and chemical defects. This strategy of dual defects may provide new insights into the improvements of AZIBs performance.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
Nanoscale Advances
·
2021
·Vol. 3
·期 8
·2334-2342
·
IF 4.553
Senlin Qu,Xin Yuan,Yu Li,Xingyang Li,Xiujuan Zhou,Xiaogang Xue,Kexiang Zhang,Juan Xu,Changlai Yuan
The composition and defect tolerance of CuInSe2 (CISe) quantum dots (QDs) provide a scaffold to design defects via tailoring the elemental ratio or distributions for boosting photocatalytic H2 evolution (PHE). Herein, a ligand-assisted two-step aqueous method was developed to prepare defect CISe quantum dots for the first time. UV-vis, XPS, HRTEM, and HADDF investigations confirmed the typical double-absorption edges of copper vacancy defects and indium substituted at copper site defects in the structure constructed through initial synthesis tuned by Cu/In ratio and the ensued coarsening. The steady-transient PL suggested that the D–A recombination with prolonged PL lifetime dominated the emission of composition-optimized CuInSe2 with the Cu/In ratio of 1/4 (CISe-1/4). Further transient photocurrent and electrochemical impedance spectroscopy investigations demonstrated that surface defects in the structure favor the carriers' separation/transportation. The CISe-1/4 exhibited a superior PHE rate of 722 μmol g−1 h−1, about 23 times higher than that of the initially synthesized CISe-1/4 nucleus (31 μmol g−1 h−1), with a maximum apparent quantum efficiency (AQE) of 1.3%. The analysis of energy levels and the coulombic interaction energy of electron–hole (Je/h) based on Raman, extending UV-vis spectra investigations suggested that surface defects resulted in decreased Je/h of CISe-1/4, favoring the enhanced PHE of this structure. This work is expected to provide a reference for designing effective non-noble metal I–III–VI photocatalysts.
研究领域:
材料科学
·
化学
·
能源科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Applied Materials Today
·
2021
·
IF 10.041
Rencheng Zhuang,Dekai Zhou,Xiaocong Chang,Yi Mo,Guangyu Zhang,Longqiu Li
Design and synthesis of electric-driven micro/nanomotors (EDMNMs) have attracted tremendous attention because of their unique advantages, such as non-necessity of fuel, high mobility, and flexible controllability. However, existing EDMNMs are mostly Janus structures based on two hemispheres made from heterogeneous materials . Here, we propose a new type of defective electric-driven micro/nanomotor with an asymmetric shape. It is found, for the first time, that the defective golden micro/nanomotors (DGMs) can generate a locally asymmetric field gradient through the topological defect, and can achieve controllable self-dielectrophoresis (sDEP) and induced-charge electrophoresis (ICEP) motion behaviors in different frequency ranges. In particular, the DGMs can achieve three-dimensional helical motion behavior through designing their defective structure. Furthermore, we demonstrate that the DGMs can attract or repel cargos under different electric frequencies. These new DGMs and their attractive performance pave the way for fabricating highly controllable EDMNMs via structural design and can be widely applied in biomedicine, micro/nanosensors, and micro/nanomechanical systems.
研究领域:
材料科学
·
生物医学工程
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2021
·
IF 19.503
Ni Luo,Cheng Chen,Dingming Yang,Wenyuan Hu,Faqin Dong
In the field of photocatalysis , one focus is on high-performance visible light catalysis. For this study, which follows the defect engineering strategy, ultrathin two-dimensional (2D) S defect-rich MoS 2 nanosheets were created in situ by ball-milling MoS 2 nanosheets with ascorbic acid and then used for the removal of Cr(VI) from wastewater. The results show that ascorbic acid increases both the specific surface area of MoS 2 nanosheets and the concentration of S stripping-defects significantly. Of the samples, D-MoS 2 -3 (i.e., S defect-rich ultrathin 2D MoS 2 nanosheets) exhibited the best Cr(VI) adsorption capacity and photocatalytic activity thanks to its large specific surface area and a high concentration of total S defects (18.5%), 311.1% better than for P-MoS 2 (i.e., pristine MoS 2 nanosheets) (4.5%). The concentration of S point-defects in D-MoS 2 -3 is only a little greater than in P-MoS 2 , but the concentration of S stripping-defects is significantly greater. S point-defects at such a high concentration readily act as recombination centers for photogenerated carriers. By contrast, S stripping-defects that lack dangling Mo-S bonds trap photogenerated holes and add to the separation efficiency of photogenerated electron-hole pairs. As a consequence, the photocatalytic performance of D-MoS 2 -3 in removing Cr(VI) is significantly better. Given this finding, the present study offers a new design pathway and a reference for the practical application of defect engineering to ultrathin 2D materials.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2023
·
IF 4.7
Yingzhang Shi,Ke Xie,Zhiwen Wang,Cheng Liu,Sen Lin,Ling Wu,Shijing Liang
Bi 2 MoO 6 hierarchical microspheres (BMO-SP) consisting of monolayer nanosheets with abundant surface oxygen defects and unsaturated Mo sites are constructed for the one-pot synthesis of secondary amine via a photocatalytic coupling reaction of nitrobenzene (NB) and benzyl alcohol (BA). The performance of this photocatalyst is 12 times higher than that of bulk Bi 2 MoO 6 (BMO-bulk). Experiment results and density functional theory calculations reveal that surface oxygen defects induce more unsaturated Mo atoms facilitating the coordination activation of NB and BA molecules through the formation of –N–O···Mo and –C–O···Mo coordination, respectively. The surface oxygen defects also promote the separation of photogenerated carriers. More photogenerated holes transfer to the surface for oxidizing the activated BA while the photogenerated electrons are trapped by oxygen defects for reducing NB. Thus, the photocatalytic performance is markedly improved. This work successfully designs an efficient photocatalyst for the tandem reaction via surface defect engineering.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
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