Inorganic Chemistry Frontiers
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2022
·Vol. 10
·期 4
·1215-1224
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IF 7.779
Jiaqi Ding,Hangren Li,Guoqiang Xi,Jie Tu,Jianjun Tian,Linxing Zhang
The wide band gap of bismuth ferrate-based materials limits their application in optoelectronic devices, and how to achieve band gap modulation in the simplest manner is the primary requirement for their industrialization. BiFeO3 (BFO) films can achieve narrower bandgaps than those under substrate strain, interphase strain, or chemical strain. In this study, we have achieved simultaneously increased tetragonality and reduced bandgaps in the tetragonal-like phase BFO-based films through chemical strain. Co substitution can be controlled by both stoichiometric ratios and atomic deposition rates. The tetragonality can increase up to a large c/a of 1.239, and the bandgap can decrease to 1.45 eV from 2.21 eV. The oxygen vacancies are closely related to the decrease of the band gap. Density functional theory calculations indicate that the introduction of Co and oxygen vacancies essentially reduced the conduction band bottom, resulting from the hybridization energy levels of Co 3d and O 2p, respectively. This paper provides a new strategy for the regulation of the optical band gap of BFO and further reveals its underlying mechanism.
研究领域:
材料科学
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物理学
·
光学工程
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Nan Xin,Yifei Li,Guihua Tang,Tian Lan,Jimin Xu,Xin Zhao,Min Zhang,Yinan Nie,Hao Shen
Thermoelectric materials have great potential in the energy recovery and environmental protection, and thermoelectric films can also effectively achieve heat dissipation of the chip through thermoelectric refrigeration. WS 2 films show good thermoelectric performance in prediction, but the figure of merit ( ZT ) of the synthesized WS 2 films still needs improvement. In this work, Cu was doped into WS 2 films by magnetron sputtering combined with chemical vapor deposition and sulfurization annealing. Cu doping narrowed the band gap and increased the hole concentration from 5.6 × 10 19 cm −3 to 2.2 × 10 21 cm −3 , greatly improved the electrical properties of WS 2 film. At 300 K, the electrical conductivity and power factor of Cu-doped films increased by 1086 % and 575 % compared to pristine WS 2 , respectively. In addition, Cu doping reduced the grain size and introduced more grain boundaries, which decreased the in-plane thermal conductivity to as low as 0.22 W m −1 K −1 at 300 K. The coupling of the electrical and thermal properties optimization greatly improved ZT . The ZT value of Cu 5.5 -WS 2 films is as high as 0.181 at 425 K. This work provides a new idea for improving the thermoelectric performance of transition metal dichalcogenides (TMDCs) films.
研究领域:
材料科学
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能源技术
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DOI
高影响因子
Materials Today Energy
·
2019
·
IF 0
Jingwei Xiu,Yangfan Shao,Linxun Chen,Yue Feng,Junfeng Dai,Xusheng Zhang,Yi Lin,Yudong Zhu,Zhenggang Wu,Yini Zheng,Hui Pan,Chang Liu,Xingqiang Shi,Xin Cheng,Zhubing He
Owning the merits of both lead-free and air-stable, the double-perovskite Cs 2 AgBiBr 6 has attracted increasing attention, but suffers low visible-light absorption coefficient due to its large indirect bandgap. Moreover, the electronic structure of its synthesized films has not been explored clearly yet. In this work, we developed a general and promising method to fabricate continuous, uniform and highly orientated Cs 2 AgBiBr 6 films in large scale on various substrates through capillary-assisted dip-coating method. Strikingly, those optimized films are single crystalline verified by φ-scan XRD . Its electronic structure was carefully studied independently by multi-photo-physical characterizations. Its bandgap can be tuned from 2.65 to 2.25 eV by changing the substrate temperature in growth from 40 to 160 °C. Essentially, their work-function (WF) was determined at −5.01 eV and WF-VBM is around 2 eV. This novel band structure with typical n-type characteristic, was further confirmed by DFT calculations, which reveals that the Cs interstitials and Br vacancies derived deep defect levels were fixed around its Fermi level, closer to the conduction band. This conclusion is different from its widely accepted p-type feature, but definitely deepens our understanding of this material and inspires us to find more valuable strategies of modulating its band structure and optoelectronic properties.
研究领域:
材料科学
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光电化学
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DOI
INORGANIC CHEMISTRY
·
2023
·
IF 4.6
Xuan Jiang,Zhaodong Nan
Multiple oxidation states of first-row transition-metal cations were always doped in g-C3N4 to enhance the catalytic activity by the synergistic action between the cations in the Fenton-like reaction. It remains a challenge for the synergistic mechanism when the stable electronic centrifugation (3d10) of Zn2+ was used. In this work, Zn2+ was facilely introduced in Fe-doped g-C3N4 (named xFe/yZn-CN). Compared with Fe-CN, the rate constant of the tetracycline hydrochloride (TC) degradation increased from 0.0505 to 0.0662 min–1 for 4Fe/1Zn-CN. The catalytic performance was more outstanding than those of similar catalysts reported. The catalytic mechanism was proposed. With the introduction of Zn2+ in 4Fe/1Zn-CN, the atomic percent of Fe (Fe2+ and Fe3+) and the molar ratio of Fe2+ to Fe3+ at the catalyst’s surface increased, where Fe2+ and Fe3+ were the active sites for adsorption and degradation. In addition, the band gap of 4Fe/1Zn-CN decreased, leading to enhanced electron transfer and conversion from Fe3+ to Fe2+. These changes resulted in the excellent catalytic performance of 4Fe/1Zn-CN. Radicals •OH, •O2–, and 1O2 formed in the reaction and took different actions under various pH values. 4Fe/1Zn-CN exhibited excellent stability after five cycles under the same conditions. These results may give a strategy for synthesizing Fenton-like catalysts.
研究领域:
材料科学
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环境催化
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产品关联
DOI
PubMed
高影响因子
OPTICAL MATERIALS
·
2024
·
IF 3.8
Wangchao Wan,Jindou Shi,Chen Zhang,Zheyuan Da,Junnan Wang,Qing Yao,Youlong Xu,Minqiang Wang
Thin films of organic halogenated perovskite MAPbX 3 (X = Cl, Br, I or mixed, CH 3 NH 3 = MA) display exceptional optical and electronic properties, rendering them highly promising materials for next-generation optoelectronics. However, achieving a large, thin, and smooth film poses a considerable challenge. Compared with the traditional spraying method, the atomized deposition method is able to break down the precursor solution molecules in the atomization system, and this method produces films with thinner thicknesses(800–1000 nm), smoother surfaces, high light transmittance and low surface roughness. By investigating the deposition time, annealing temperature, and film stability associated with the atomized deposition technique, we determined the optimal process parameters for producing nanometer-thick perovskite films. Specifically, we set the precursor solution concentration to 0.1 mmol/L, the deposition time to 450 s, added PVDF (polyvinylidene fluoride) colloid at a concentration of 3 wt%, and maintained an annealing temperature of 80 °C for 20 min. Ultimately, perovskite films with tunable bandgap were prepared for anti-counterfeit marking applications. This method of preparing perovskite films represents a significant advancement towards their commercial utilization in the realm of optoelectronic materials.
研究领域:
材料科学
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光学工程
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产品关联
DOI
高影响因子
CRYSTENGCOMM
·
2023
·Vol. 25
·期 43
·6091-6095
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IF 3.1
Jing Huang,Minghao Li,Zhanhui Liu,Jingyan Hua,Hui Zeng,Yunyun Chen,Jing Su
In this work, copper-based halides Cs2CuCl4, Cs2CuBr4 and mixed-halides Cs2CuCl2.8Br1.2, Cs2CuCl2Br2 and Cs2CuCl1.2Br2.8 single crystals were grown via the evaporation method using deionized water as a solvent. The structure and actual element component of the Cs2Cu(Cl, Br)4 crystals were studied using XRD and EDS. The halides of Cs2Cu(Cl, Br)4 exhibit both good light absorption and PL performance. The absorption peaks related to LMCT electron transition bands were observed, and the tunable band gap was obtained by adjusting the Br−/Cl− ratio. PL spectra show purple, blue, and green luminescence, and the luminescence mechanism was analyzed. Our study indicates that the Cs2Cu(Cl, Br)4 halides have application prospects in optoelectronic devices.
研究领域:
材料科学
·
光学
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DOI
高影响因子
MATERIALS LETTERS
·
2023
·
IF 3
Caichao Wang,Yan Zhu,Kang Xu,Shuhong Sun,Mingrong Dong,Jinkun Liu,Yongmao Hu
Semiconductors Ag 8 SnS 6 (ATS) nanoparticles were synthesized by a simple one-pot method. Meanwhile, Se was added to the ATS process to form semiconductors Ag 8 SnS 6-x Se x (ATSSe) (x = 0.0, 0.2, 0.4, 0.6, 0.8) nanoparticles. The prepared ATS nanoparticles were mainly triangle in shape with grain sizes ranging from 15 ∼ 60 nm, and ATSSe nanoparticles were formed after the addition of Se during the synthesis process. Phase transformation of the synthesized nanoparticles rhombohedral crystalline ATS to cubic ATSe was observed for Se substitution ratios x in the range of 0.2 ∼ 0.8. The band gap of ATSSe nanoparticles was in the range of 1.16 ∼ 0.85 eV. This finding suggests that Se substitution is an effective method to regulate the band gap and structure of ATS.
研究领域:
材料科学
·
化学
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产品关联
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2022
·Vol. 9
·期 17
·4359-4368
·
IF 7.779
Guiqiang Wang,Jiayu Bi,Jiarun Chang,Miao Lei,Huiling Zheng,Yu Yan
Narrowing the bandgap and promoting the quality of inorganic perovskites are the key points to improve the performance of inorganic perovskite solar cells. Herein, we incorporate Sn2+ into an inorganic CsPbBr3 perovskite to simultaneously tune the bandgap and improve the quality of the perovskite film. The density functional theory calculations demonstrate that the incorporation of Sn2+ leads to an obvious shift of the conduction band minimum of the CsPbBr3 perovskite towards the lower energy region. Therefore, the bandgap of CsPb1−xSnxBr3 perovskites is gradually reduced with the increase of the Sn2+ content. Additionally, when Pb2+ is substituted with an appropriate amount of Sn2+, the doped perovskite films display largely promoted quality compared to the undoped one. These advantages lead to the suppression of charge recombination and the enhancement of light harvesting in the as-fabricated perovskite solar cells (PSCs). Consequently, the CsPb0.95Sn0.05Br3-based PSC with a structure of FTO/TiO2 layer/perovskite/carbon delivers a greatly promoted power conversion efficiency of 8.04% compared with the efficiency of 5.93% for the controlled device. Moreover, the CsPb0.95Sn0.05Br3 PSC without any encapsulation preserves over 91% of its initial efficiency after 720 h of storage in ambient air, suggesting an excellent stability.
研究领域:
材料科学
·
能源科学
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DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2020
·
IF 4.939
Qiaoqi Li,Lili Zhang,Chao Tang,Pusu Zhao,Chengzhu Yin,Jingzhou Yin
The systematic investigation of In 3+ ions doped ZnGa 2 O 4 applying to photocatalytic H 2 evolution (PHE) under simulated solar-light irradiation was first reported here. A series of Zn(In x Ga 1- x ) 2 O 4 ( x = 0 to 0.4) solid-solutions were obtained by sol-gel method and characterized by XRD , SEM, elemental mapping, XPS , UV–Vis DRS and N 2 adsorption measures. The concentration of In 3+ ions remarkably enhanced the light-harvesting capability of Zn(In x Ga 1- x ) 2 O 4 solid-solutions in the visible-light region, and successfully regulated the positions of the CB-bottom potential, ultimately improving the photocatalytic capabilities under simulated solar-light irradiation. Among composites containing different In 3+ ions dosages, Zn(In 0.1 Ga 0.9 ) 2 O 4 demonstrated the most excellent photocatalytic capability for solar-light-driven PHE reaction (H 2 : 240.6 μ mol/h/g), in which the stability of the Zn(In 0.1 Ga 0.9 ) 2 O 4 was confirmed by several techniques.
研究领域:
材料科学
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能源化学
·
环境科学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Yi Wang,Geng Chen,Hanqin Weng,Lan Wang,Jialiang Chen,Sheng Cheng,Peng Zhang,Mozhen Wang,Xuewu Ge,Hongbing Chen,Wei Huang,Mingzhang Lin
Effectively separating uranium from aqueous solution is pivotal in the sustainable development of the nuclear industry and environmental protection. In this work, non-metal photocatalysts, carbon-doped BN (BCN) nanosheets were used to extract uranium by the photocatalytic reduction technique, and the doping in the form of carbon rings can regulate the bandgap and electronic structure by manipulating carbon amount. Benefiting from the porous structure and strong visible-light absorption, the U(VI) separation ratio of 97.4% could be achieved after 1.5-hour visible irradiation with an apparent rate value of 2.97 h −1 over BCN-80. Additionally, BCN-80 displayed good reusability and stability with the U(VI) separation ratio > 90% even after five cycles, and the enhanced U(VI) photoreduction was attributed to the synergistic effect of photoinduced electrons and formed ketyl radicals. This work demonstrates the great potential of BCN materials in U(VI) enrichment and will lay the foundation for further developing novel semiconductor photocatalysts.
研究领域:
材料科学
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环境科学
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核能技术
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DOI
高影响因子
Journal of Materials Chemistry C
·
2015
·Vol. 3
·期 34
·8844-8851
·
IF 4.696
Sheng Cao,Jialong Zhao,Weiyou Yang,Chengming Li,Jinju Zheng
In the present work, we reported the synthesis of Mn2+-doped Zn–In–S quantum dots (QDs) with high optical performance in a controlled manner. The effects of the temperature, the introduced ODE-S amount and Zn/In ratios in the raw materials, as well as the Mn2+ doping concentrations on the photoluminescence (PL) properties of Mn2+-doped Zn–In–S QDs were investigated systematically. The resultant QDs exhibit tunable bandgaps ranging from 2.9 to 3.7 eV, well-resolved Mn2+ d–d emission with a PL quantum yield (QY) of 56% and a surprisingly long excited state lifetime up to ∼4.2 ms, suggesting their excellent PL properties. Meanwhile, the initial high PL QY of the obtained Mn2+-doped Zn–In–S QDs in organic solvents could be preserved very well once they were transferred into aqueous media via ligand exchange. Furthermore, the as-synthesized QDs exhibit excellent thermal stability up to 200 °C in a crude solution.
研究领域:
材料科学
·
光学
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产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Nan Xin,Guihua Tang,Tian Lan,Yifei Li,Jiawei Kou,Min Zhang,Xin Zhao,Yinan Nie
Two-dimensional (2D) layered transitional metal dichalcogenides (TMDCs) semiconductors like MoS 2 have been predicted to be promising thermoelectric (TE) materials due to their high carrier mobility. However, the TE performance of MoS 2 film is severely hindered by the high in-plane thermal conductivity. In this work, based on reversing grain orientation reducing in-plane thermal conductivity, Cu doping is used to increase the carrier concentration for optimization of electrical properties. The Cu-doped MoS 2 films have prepared by magnetron sputtering (MS) combined with post-sulfurization chemical vapor deposition (CVD). The composition, structure, thermal and electrical properties were systematically investigated by experiment and DFT calculation. Results indicate that Cu doping may slightly reduce the Seebeck coefficient of MoS 2 film, but effectively narrow the band gap and improve the carrier concentration, thus improving the electrical performance. In addition, MS combined with CVD method can effectively increase the degree of grain misorientation, making the in-plane thermal conductivity of Cu-doped MoS 2 film much lower. Combined with the above optimization, a promising maximum ZT value among TMDCs 0.137 at 425 K was obtained in Cu 6 -MoS 2 film. This study provides a new strategy to synchronously regulate the thermal and electrical properties of TMDCs films to improve their thermoelectric performances.
研究领域:
材料科学
·
热电学
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产品关联
DOI
高影响因子
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