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Journal of Materials Science & Technology 2022年第24期119卷 200-208页

作者： Yameng Jiao Qiang Song Xuemin Yin liyuan han Wei Li Hejun Li State Key Laboratory of Solidification Processing Shannxi Province Key Laboratory of Fiber Reinforced Light Composite MaterialsCarbon/Carbon Composites Research CenterNorthwestern Polytechnical UniversityXi’an 710072China

Due to the limited electromagnetic wave(EMW)loss capacity and agglomeration,carbon black(CB)gradually fails to meet the increasingly harsh demanding conditions.Herein,defect-rich bamboo-like carbon nanotubes(CNTs)were grown on CB by the process of chemical vapor deposition.CNTs prepared in situ on CB can assist it to build a developed multilevel conductive network and introduce plentiful CB/CNTs nano-interfaces.What’s more,the defects that accompany the growth of CNTs endow CNTs with a moderate conductivity and good impedance matching,thereby causing an effective microwave absorption(MA).Meanwhile,the high-density defects on CNTs can induce dipole polarization to further strengthen the EMW loss ability.The influence of CNTs with different growth time on MA performance has been explored.Profiting from the structural merits,the synthesized CB-CNT with CNTs growth time of 40 min exhibits the optimal absorbing property,which has the minimum reflection loss of-53.6 d B and maximum effective absorption bandwidth of 4.1 GHz with the thickness of 2.7 mm,covering almost the entire X band.The introduction of defect-rich CNTs significantly enhances the EMW loss ability of CB,which provides a rational strategy for the design of high-efficient microwave absorption materials.

关键词： Microwave absorption Carbon nanotubes Defect-rich Conductive network Interface polarization

Stable perovskite solar cells with 23.12% efficiency and area over 1 cm^(2) by an all-in-one strategy

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Science China Chemistry 2022年第7期65卷 1321-1329页

作者： Hongzhen Su Xuesong Lin Yanbo Wang Xiao Liu Zhenzhen Qin Qiwei Shi Qifeng han Yiqiang Zhang liyuan han State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240China Special Division of Environmental and Energy Science Komaba Organization for Educational Excellence(KOMEX)College of Arts and SciencesUniversity of TokyoTokyo 153-8902Japan School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China SJTU-Paris Elite Institute of Technology Shanghai Jiao Tong UniversityShanghai 200240China School of Materials Science and Engineering Henan Institute of Advanced TechnologyZhengzhou UniversityZhengzhou 450001China

To realize the commercialization of perovskite solar cells(PSCs), it is required to overcome the remaining challenges in device enlargement and operational stability. Here, we report an all-in-one strategy by integrating the oxidation of hole-transport material(HTM) with the formation of the passivation layer, which simultaneously solved the stability issues caused by HTM oxidation and realized the uniform defects in passivation over a large area. The resulting devices achieved a certified PCE of23.12% on average with an aperture area of 1.04 cm^(2) and are reproducible with high operational stability because of the exclusion of air exposure, hygroscopic Li-TFSI, and the lithium-based wastes, maintaining ca. 90% of their initial PCEs after operation at the maximum power point under continuous 1 sun illumination for 1,600 h. Our strategy simplifies the fabrication process of PSCs, which is compatible with commercial-scale methods, offering facile access to efficient and stable large-area PSCs.

关键词： perovskite solar cells oxidation of hole-transport materials uniform defects passivation

Two birds with one stone: Simultaneous fabrication of HfC nanowires and CNTs through efficient utilization of polymer-derived ceramics

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Journal of Materials Science & Technology 2022年第34期129卷 163-172页

作者： Yanqin Fu Yulei Zhang Xuemin Yin liyuan han Qiangang Fu Hejun Li Ralf Riedel Shaanxi Province Key Laboratory of Fiber Reinforced Light Composite Materials Northwestern Polytechnical UniversityXi’an 710072China Technische Universität Darmstadt Institut für MaterialwissenschaftOtto-Berndt-Straβe 3Darmstadt D-64287Germany

Carbon nanotubes(CNTs) are fabricated in carbon cloth by ultilizing the waste gasses when fabricating hafnium carbide nanowires(HfC_(NWS)) through thermal pyrolysis of Hf-containing polymer precursor.The formed HfC_(NWS) are distributed uniformly on the surface of the carbon fibers in carbon/carbon(C/C) composites and display perfect single crystal appearance.The pyrolysis of the Hf-containing organic precursor provides hafnium and carbon source for the growth of HfC_(NWS).The released waste gasses containing CO,CH4and CO_(2)are the main carbon source for the growth of CNTs.Specifically,the flexural strength of HfC_(NWS) reinforced carbon/carbon(HfC_(NWS)-C/C) composites is enhanced by ~105% compared with pure C/C,and the CNTs/carbon cloth also displays improved electrochemical performance with respect to capacitor applications.The present study introduces a novel sustainable and eco-friendly process related to polymer-derived ceramics to form advanced ceramic nanocomposites and proposes a deep understanding of the growth mechanism of CNTs.

关键词： HfC nanowires Carbon nanotubes Waste gasses Effective utilization Polymer-derived ceramics

Heterogeneous FASnI3 Absorber with Enhanced Electric Field for High-Performance Lead-Free Perovskite Solar Cells

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Nano-Micro Letters 2022年第6期14卷 234-247页

作者： Tianhao Wu Xiao Liu Xinhui Luo Hiroshi Segawa Guoqing Tong Yiqiang Zhang Luis KOno Yabing Qi liyuan han State Key Laboratory of Metal Matrix Composites School of Material Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240People’s Republic of China Special Division of Environmental and Energy Science Komaba Organization for Educational Excellence(KOMEX)College of Arts and SciencesUniversity of TokyoTokyo 153-8902Japan Energy Materials and Surface Sciences Unit(EMSSU) Okinawa Institute of Science and Technology Graduate University(OIST)1919-1 TanchaOnna-sonKunigami-gunOkinawa 904-0495Japan School of Materials Science and Engineering Henan Institute of Advanced TechnologyZhengzhou UniversityZhengzhou 450001People’s Republic of China

Lead-free tin perovskite solar cells(PSCs)have undergone rapid development in recent years and are regarded as a promising ecofriendly photovoltaic technology.However,a strategy to suppress charge recombination via a built-in electric field inside a tin perovskite crystal is still lacking.In the present study,a formamidinium tin iodide(FASnI;)perovskite absorber with a vertical Sn;gradient was fabricated using a Lewis base-assisted recrystallization method to enhance the built-in electric field and minimize the bulk recombination loss inside the tin perovskites.Depth-dependent X-ray photoelectron spectroscopy revealed that the Fermi level upshifts with an increase in Sn;content from the bottom to the top in this heterogeneous FASnI;film,which generates an additional electric field to prevent the trapping of photo-induced electrons and holes.Consequently,the Sn;-gradient FASnI;absorber exhibits a promising efficiency of 13.82%for inverted tin PSCs with an open-circuit voltage increase of 130 mV,and the optimized cell maintains over 13%efficiency after continuous operation under 1-sun illumination for 1,000 h.

关键词： Gradient FASnI3 absorber Built-in electric field Bulk charge recombination Lead-free perovskite solar cell

An In-Situ Formed Tunneling Layer Enriches the Options of Anode for Efficient and Stable Regular Perovskite Solar Cells

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Nano-Micro Letters 2023年第1期15卷 197-208页

作者： Xuesong Lin Yanbo Wang Hongzhen Su Zhenzhen Qin Ziyang Zhang Mengjiong Chen Min Yang Yan Zhao Xiao Liu Xiangqian Shen liyuan han State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240People’s Republic of China Special Division of Environmental and Energy Science Komaba Organization for Educational ExcellenceCollege of Arts and SciencesUniversity of TokyoTokyo 153-8902Japan

Perovskite solar cells(PSCs)are taking steps to commercialization.However,the halogen-reactive anode with high cost becomes a stumbling block.Here,the halogen migration in PSCs is utilized to in situ generate a uniform tunneling layer between the hole transport materials and anodes,which enriches the options of anodes by breaking the Schottky barrier,enabling the regular PSCs with both high efficiency and stability.Specifically,the regular PSC that uses silver iodide as the tunneling layer and copper as the anode obtains a champion power conversion efficiency of 23.24%(certified 22.74%)with an aperture area of 1.04 cm^(2).The devices are stable,maintaining 98.6%of the initial effi-ciency after 500 h of operation at the maximum power point with continuous 1 sun illumination.PSCs with different tunneling layers and anodes are fabricated,which confirm the generality of the strategy.

关键词： Perovskite solar cell Anode Halogen migration In situ tunneling layer

Research activities on perovskite solar cells in China

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Science China Chemistry 2019年第7期62卷 822-828页

作者： Yanbo Wang liyuan han State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University

Perovskite solar cells(PSCs) have attracted much attention because of their high efficiencies and low costs for production.Although academic research started late in China, compared to that in Europe and Korea, the majority of active PSC research is now conducted in China;furthermore, Chinese research groups currently hold the certified highest efficiency record for both an individual PSC and a PSC module. China is also the world’s largest supplier of solar modules, making it a promising country in which to realize the commercialization of PSCs. Herein, we review PSC research activities undertaken in China(both academic and industrial) and discuss significant remaining challenges to overcome for early commercialization of PSCs. We propose that research activities shift away from material and device structure development toward improving PSC stability and developing methods for large-area module fabrication. In addition, we suggest that a recognized certification center is urgently needed in China to further accelerate PSC research.

关键词： perovskite solar cell high efficiency stability commercialization China

Self-assembled interlayer aiming at the stability of NiOx based perovskite solar cells

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Journal of Energy Chemistry 2022年第6期31卷 211-220,I0006页

作者： Tonghui Guo Zhi Fang Zequn Zhang Zhiqiang Deng Rui Zhao Jing Zhang Minghui Shang Xiaohui Liu Ziyang Hu Yuejin Zhu liyuan han Department of Microelectronic Science and Engineering Ningbo UniversityNingbo 315211ZhejiangChina School of Materials Science and Engineering Ningbo University of TechnologyNingbo 315016ZhejiangChina State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240China

Inorganic NiO_(x) based inverted structure perovskite solar cells (PSCs) is reported to be more stable than that with the organic hole transport materials.In this work,NiO_(x)/MAPbI_(3) interface chemical reaction induced instability of perovskite is unveiled:Ni^(3+) and I^(-) exhibit redox reactions and deprotonation of MA^(+) happens,which result in interface defects and perovskite lattice deformation.Thus the defective interface accelerates the degradation of perovskite by defect pathways from the bottom interface to the perovskite surface contacting H_(2)O/O_(2).Self-assembled interlayer of NH_(2)^(-)end silane on NiO_(x)separates the reactive NiO_(x)and MAPbI_(3),tunes the interface energy states by–NH_(2) end group.As a result,the PSC based on the silane treated NiO_(x)achieves enhanced PCE of 20.1%with decent stability under environmental and extreme conditions (high temperature,high humidity,light infiltration).Our work highlights the interface chemical problem induced PSC instability and a simple interface modification to achieve the stable PSCs.

关键词： Perovskite solar cells Interface chemical problem NiOx hole transport material Self assemble Stability

Optimization of Callus Induction Conditions from Immature Embryos of Maize under Stress

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Phyton-International Journal of Experimental Botany 2022年第9期91卷 1945-1957页

作者： Xiaotong Wei Xuhong Fan Xuan Lu liyuan han Honglin Zhang Siyan Liu Jing Qu Shuyan Guan Yiyong Ma College of Life Sciences Jilin Agricultural UniversityChangchun130118China Jilin Academy of Agricultural Sciences Changchun130118China Joint Laboratory of International Cooperation in Modem Agricultural Technology of Ministry of Education Jilin Agricultural UniversityChangchun130118China

The embryos of maize(Zea mays L.)inbred lines GS02,GS07,GS08,GS11 and GS15 were used as receptor materials to optimize the receptor system from the aspects of genotype,medium components and stress(PEG6000,mannitol,salt and low phosphorus).The results showed that GS07 had the highest induction rate(95.2%).Orthogonal test analysis showed that the best combination of medium components in induction was A2B3C1D3(2),namely,the concentration of 2,4-dichlorophenoxy acetic acid(2,4-D)was 4 mg·mL^(-1),the concentration of L-Proline(L-Pro)was 0.8 mg·mL^(-1),and the concentration of silver nitrate(AgNO3)was 10 mg·mL^(-1)(or 5 mg·mL).Interestingly,we found that the optimal medium supplemented with 30 g·L^(-1)PEG6000 or 80 g·L^(-1)mannitol was suitable for antioxidant enzyme activity and malondialdehyde(MDA)content in GS07 callus.Exogenous 10 mmol·L^(-1)Ca^(2+)in the medium components with 100 mmol·L^(-1)sodium chloride(NaCl)could improve the activity of antioxidant enzymes in GS07 callus.Callus of GS07 could divide normally and grow well in medium components with 27 mg·L^(-1)KH_(2)PO_(4).This study enhanced the adaptability of maize callus to stress and optimized the culture conditions.

关键词： Maize immature embryo adversity stress medium optimization

Perovskite films with gradient bandgap for self-powered multiband photodetectors and spectrometers

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Nano Research 2023年第7期16卷 10256-10262页

作者： Chuantian Zuo Lixiu Zhang Xiyan Pan He Tian Keyou Yan Yuanhang Cheng Zhiwen Jin Chenyi Yi Xiaoliang Zhang Wu-Qiang Wu Qinye Bao liyuan han Liming Ding Center for Excellence in Nanoscience(CAS) Key Laboratory of Nanosystem and Hierarchical Fabrication(CAS)National Center for Nanoscience and TechnologyBeijing 100190China School of Physics and Electronic Science East China Normal UniversityShanghai 200241China School of Integrated Circuits Tsinghua UniversityBeijing 100084China School of Environment and Energy South China University of TechnologyGuangzhou 510000China School of New Energy Nanjing University of Science and TechnologyJiangyin 214443China School of Physical Science and Technology Lanzhou UniversityLanzhou 730000China State Key Laboratory of Power System Department of Electrical EngineeringTsinghua UniversityBeijing 100084China School of Materials Science and Engineering Beihang UniversityBeijing 100191China School of Chemistry Sun Yat-sen UniversityGuangzhou 510006China State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240China Key Laboratory of Semiconductor Materials Science Beijing Key Laboratory of Low Dimensional Semiconductor Materials and DevicesInstitute of SemiconductorsChinese Academy of SciencesBeijing 100083China

Bandgap-graded materials present varying spectral responses at different positions,making them possible to be used as an alternative to photoactive materials array in multi-spectral responsive devices,thus miniaturizing the apparatus.However,the preparation of bandgap-graded materials usually requires complicated deposition process.Here we report a facile lowtemperature solution process to make films with lateral bandgap gradients,which form spontaneously via self-spreading and interdiffusion of solutions.We show lead halide perovskite films with MAPbCl_(3)-MAPbBr_(3)and MAPbBr_(3)-MAPbI_(3)gradients,which exhibit light absorption onsets ranging from 410 to 781 nm.The bandgap-graded films were used to make self-powered multiband photodetectors,which show different spectral responses at different positions without applying bias voltage.Furthermore,self-powered spectrometers were made by using the multiband photodetectors.

关键词： self-spreading interdiffusion bandgap-graded perovskite multiband photodetectors self-powered spectrometers

Enhancing both strength and toughness of carbon/carbon composites by heat-treated interface modification

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Journal of Materials Science & Technology 2019年第3期35卷 383-393页

作者： Jiajia Sun Hejun Li liyuan han Qiang Song State Key Laboratory of Solidification Processing Northwestern Polytechnical University

A simple method to increase both strength and toughness of carbon/carbon(C/C) composites is presented.This method is based on the heat treatment of the pre-deposited thin carbon coating, leading to the formation of more orderly pyrolytic carbon(PyC) as a functional interlayer between fiber and matrix that could optimize the interfacial sliding strength in C/C composites. Effects of such a heat-treated PyC layers on the microstructure, tensile strength and fracture behavior of unidirectional C/C composites were investigated. Results showed that although the in-situ fiber strength was deteriorated after the introduction of interfacial layer, tensile strength of the specimen was greatly improved by 38.5% compared with pure C/C composites without any treatment. The interfacial sliding stress sharply decreased, which was interpreted from finite element analysis and verified by Raman spectra. Therefore, the fracture behavior was changed from brittle fracture to multiple-matrix cracking induced non-linear mechanical behavior.Finally, the ultimate strength can be predicted by different models according to the interfacial sliding stress. Our research would provide a meaningful way to improve both strength and toughness of C/C composites.

关键词： Carbon/carbon composites Tensile strength Interface Heat treatment