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Effect of rubrene:P3HT bilayer on photovoltaic performance of perovskite solar cells with electrodeposited ZnO nanorods

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Journal of Energy Chemistry 2018年第2期27卷 455-462页

作者： Christian Mark Pelicano Hisao Yanagi Graduate School of Materials Science Nara Institute of Science and Technology

Improved photovoltaic performance of perovskite solar cells is demonstrated through the synergistic effect of electrodeposited ZnO nanorods and rubrene：P3HT bilayer as electron and hole-transporting layers,respectively. Highly crystalline ZnO nanorods were obtained by electrochemical deposition in a chloride medium. Additionally, rubrene interlayer was able to passivate or cover the grain boundaries of perovskite film effectively that led to reduced leakage current. A perovskite solar cell optimized with ZnO nanorods and rubrene：P3HT bilayer achieved a maximum efficiency of 4.9% showing reduced hysteresis behavior compared with the device having P3HT as the only hole-transporting layer. The application of longer nanorods led to better perovskite infiltration and shorter charge carrier path length. These results highlight the potential of electrodeposited ZnO nanorods and rubrene：P3HT bilayer as charge selective layers for efficient perovskite solar cells.

关键词： Rubrene：P3HT bilayer Electrodeposited ZnO nanorods Perovskite solar cells

Organic semiconductor nanostructures:optoelectronic properties,modification strategies,and photocatalytic applications

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Journal of materials science & Technology 2022年第18期113卷 175-198页

作者： Jiaqi Dong Chuxuan Yan Yingzhi Chen Wenjie Zhou Yu Peng Yue Zhang Lu-Ning Wang Zheng-Hong Huang school of materials science and Engineering University of Science and Technology BeijingBeijing100083China Shunde graduate school of University of science and Technology Beijing Foshan528399China Key Laboratory of Advanced materials(MOE) School of Materials Science and EngineeringTsinghua UniversityBeijing100084China

Organic semiconductors(OSCs)possess diverse chemical structures and tailored optoelectronic properties via simple chemical modifications,so increasing use of them are found in efficient visible-light photo-catalysis.However,the weak chemical bonds and the poor charge behavior(e.g.,low concentration of free charge carriers,low carrier mobility)intrinsic in them,always incur quite limited stability and efficiency.Therefore,the assembly of them into refined nanostructures or nanocomposites is usually proposed to enhance their optoelectronic properties,as well as the photocatalytic efficiency and reliability.Zero-dimensional(0D)nanoparticles are low in size and hence high specific surface area(SSA);One-dimensional(1D)nanostructures are usually arranged in an orderly long range thus leading to low surface defect density and increased carrier mobility;Two-dimensional(2D)nanostructures are particularly capa-ble of enhancing the photogenerated charge utilization because of their large reaction sites and shortened charge transport length.Furthermore,the building of heterogeneous interfaces in the nanocomposites can effectively facilitate the special charge separation.All these highlight the importance of organic nanos-tructures in improving the photocatalytic activity and stability.Therefore,organic semiconductor nanostructures(OSNs)have been increasingly used in the photocatalytic water splitting into H_(2) and O_(2),CO_(2) reduction,pollutant decomposition,disinfection,etc.In this review,we first examine the important optoelectronic properties of OSNs that govern the photocatalytic processes;we then analyze different classes of OSNs and their mechanistic pathways,with an emphasis on the structure-property relationships;we also introduced various photocatalytic applications of OSNs;we lastly propose the challenges and future outlook in real use.

关键词： Organic semiconductors Nanostructures Optoelectronic properties Photocatalysis

Discovering unusual structures from exception using big data and machine learning techniques

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science Bulletin 2019年第9期64卷 612-616页

作者： Jianshu Jie Zongxiang Hu Guoyu Qian Mouyi Weng Shunning Li Shucheng Li Mingyu Hu Dong Chen Weiji Xiao Jiaxin Zheng Lin-Wang Wang Feng Pan school of Advanced materials Peking UniversityShenzhen Graduate School materials science Division Lawrence Berkeley National Laboratory

Recently, machine learning(ML) has become a widely used technique in materials science study. Most work focuses on predicting the rule and overall trend by building a machine learning model. However,new insights are often learnt from exceptions against the overall trend. In this work, we demonstrate that how unusual structures are discovered from exceptions when machine learning is used to get the relationship between atomic and electronic structures based on big data from high-throughput calculation database. For example, after training an ML model for the relationship between atomic and electronic structures of crystals, we find AgO2 F, an unusual structure with both Ag3+and O22à, from structures whose band gap deviates much from the prediction made by our model. A further investigation on this structure might shed light into the research on anionic redox in transition metal oxides of Li-ion batteries.

关键词： Machine learning Gradient boosting decision tree Band gap Unusual structures

Controllable substitutional vanadium doping in wafer-scale molybdenum disulfide films

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Nano Research 2023年第2期16卷 3415-3421页

作者： Jihyung Seo Eunbin Son Jiha Kim Sun-Woo Kim Jeong Min Baik Hyesung Park Department of materials science and Engineering Graduate School of Semiconductor Materials and Devices EngineeringGraduate School of Carbon NeutralityLow Dimensional Carbon Materials CenterUlsan National Institute of Science and TechnologyUlsan 44919Republic of Korea school of Advanced materials science and Engineering Sungkyunkwan University(SKKU)Suwon 16419Republic of Korea SKKU Institute of Energy science and Technology Sungkyunkwan UniversitySuwon 16419Republic of Korea

Substitutional atomic doping of transition metal dichalcogenides(TMDs)in the chemical vapor deposition(CVD)process is a promising and effective strategy for modifying their physicochemical properties.However,the conventional CVD method only allows narrow-range modulation of the dopant concentration owing to the low reactivity of the precursors.Moreover,the growth of wafer-scale monolayer TMD films with high dopant concentrations is much more challenging.Herein,we report a facile doping approach based on liquid precursor-mediated CVD process for achieving high vanadium(V)doping in the MoS_(2)lattice with excellent doping uniformity and stability.The lateral growth of the host MoS_(2)lattice and the reactivity of the V precursor were simultaneously improved by introducing an alkali metal halide as a reaction promoter.The metal halide promoter enabled the wafer-scale synthesis of V-incorporated MoS_(2)monolayer film with excessively high doping concentrations.The excellent wafer-scale uniformity of the highly V-doped MoS_(2)film was confirmed through a series of microscopic,spectroscopic,and electrical analyses.

关键词： doping concentration reaction promoter substitutional doping transition metal dichalcogenides wafer-scale growth

材料基因组工程:一种有前途的高性能金属有机框架研发方法

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science Bulletin 2022年第12期67卷 1197-1200页

作者：薛祥东黄秀兵王戈 Advanced Innovation Center for materials Genome Engineering School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083China Shunde graduate school University of Science and Technology BeijingShunde 528399China

The“modular”structural features of metal–organic frameworks(MOFs),that is,inorganic nodes and organic ligands that are used as building blocks and assembled according to a certain topology,endow MOFs with an almost... 详细信息

关键词：金属有机框架 inorganic topology

All-nanofiber self-powered PTFE/PA66 device for real-time breathing monitor by scalable solution blow spinning technology

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Nano Research 2022年第9期15卷 8458-8464页

作者： Pan Li Yibo Liu Han Zhang Zhiping Hu Luna Jia Dongkui Liu Lu Yu Bo Li Youwei Yao school of materials science and Engineering Tsinghua UniversityBeijing 100084China Institute of materials Research Tsinghua Shenzhen International Graduate SchoolShenzhen 518055China

All-nanofiber self-powered device was fabricated using simple,low-cost,safe,and scalable solution blow spinning(SBS)technology for real-time respiratory monitor and timely identification of respiratory obstruction clinically.Polytetrafluoroethylene(PTFE)and polyamide-66(PA66)nanofibers were selected as triboelectric pairs,owing to strong ability to gain electrons of PTFE and supply electrons of PA66.Poly(ethylene oxide)(PEO)was added to regulate spinning solution viscosity and prepare PTFE/PEO nanofibers,and the morphology and diameter distribution of nanofibers were discussed.PTFE nanofiber film was obtained after the decomposition of PEO in PTFE/PEO nanofiber and melt flow of PTFE pellets in a limited region,and possessed a tensile strength of 1.05 MPa and elongation at a break of 288.58%.Later,PTFE/PA66 all-nanofiber self-powered device was constructed containing PA66 nanofibers,and Au deposition film was used as electrodes by magnetron sputtering.The as-obtained device showed robust electrical performance with an open circuit voltage of~110 V at a loading force of 10 N,a short-circuit current of~5 uA at a loading force of 10 N and a frequency of 4 Hz,a maximum power density of 562 mW·m^(–2),and a current of 3.1 uA at a loading resistance of 30 MΩ.Based on the triboelectric mechanism,the device possessed stable response and effective sensibility for stimuli,was used to monitor human breathing conditions,prevent suffocation,and distinguish slow,normal,and fast breathing,with an output voltage of~0.08 V perceived in one normal respiratory circle.

关键词： polytetrafluoroethylene(PTFE) nanofibers triboelectric flexible electronics

Organic photocatalysts:From molecular to aggregate level

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Nano Research 2022年第5期15卷 3835-3858页

作者： Chuxuan Yan Jiaqi Dong Yingzhi Chen Wenjie Zhou Yu Peng Yue Zhang Lu-ning Wang school of materials science and Engineering University of Science and Technology BeijingBeijing 100083China Shunde graduate school of University of science and Technology Beijing Foshan 528399China

Organic semiconductors(OSCs)have the advantages of tunable molecular structures,suitable band gaps,and exceptional optoelectronic properties.The π-π stacking ability of OSCs also leads to appealing molecular stacking structure,function,and stability.So far,organic photocatalysts have engaged in homogeneous or heterogeneous photocatalysis in the form of free molecules,supported molecules,or nanostructures.Meanwhile,researches on organic photocatalysts have expanded from small organic molecules to the organic macromolecules,as well as their various nanostructures and nanocomposites including isolated zero-dimensional(0D),one-dimensional(1D),two-dimensional(2D),three-dimensional(3D)nanostructures,and their combinations.Therefore,many versatile strategies have been explored to improve photocatalytic ability and practicality either from molecular synthetic modification,crystal,or interface engineering.In this review,we first discuss the photophysical and photochemical processes of organic photocatalysts that govern the ultimate photocatalytic efficiency;we then summarize different forms of organic photocatalysts,their rational design strategies,and mechanistic pathways,as well as their applications in H_(2) evolution,CO_(2) reduction,and environmental purification,aiming to highlight the structure/property relationships;we lastly propose ongoing directions and challenges for future development of organic photocatalysts in real use.

关键词： organic photocatalyst homogeneous photocatalysis heterogeneous photocatalysis nanostructure heterostructure

First-principles study of polarization and piezoelectricity behavior in tetragonal PbTiO_3-based superlattices

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Chinese Physics B 2018年第2期27卷 551-555页

作者：朱振业 school of materials science and Engineering Harbin Institute of Technology Shenzhen Graduate School

Using first-principles calculation, the contribution of A-site and B-site atoms to polarization and piezoelectricity d33 in the tetragonal Pb TiO_3/KNbO_3 and PbTiO_3/LaAlO_3 superlattices is investigated in this paper. It is shown that PbTiO_3/KNbO_3 superlattice has larger polarization and d33 than PbTiO_3/LaAlO_3 superlattice, because there is stronger charge transfer between A（B）-site atoms and oxygen atom in PbTiO_3/KNbO_3 superlattice. InPbTiO_3/KNbO_3 superlattice,B-site atoms（Ti, Nb） make larger contribution to the total polarization and d33 than the A-site atoms（Pb, K） because of the strong covalent interactions between the transition metal（Ti, Nb） and the oxygen atoms, while piezoelectricity in PbTiO_3/LaAlO_3 superlattice mainly ascribes to piezoelectric contribution of Pb atom and Ti atom in PbTiO_3 component.Furthermore, by calculating the proportion of the piezoelectric contribution from Pb TiO_3 component in superlattices, we find there is different response of strain to piezoelectric contribution from Pb TiO_3 component in two superlattices but still with a value larger than 50%. InPbTiO_3/KNbO_3 superlattice, the c-axis strain reduces the proportion, especially under tensile condition. Meanwhile in PbTiO_3/LaAlO_3 superlattice, Pb TiO_3 plays a leading role to the total d33, especially under compressive condition, and the proportion decreases as the tensile strain increases.

关键词： perovskite superlattice first-principles strain cation piezoelectricity

Enhanced Surface Mechanical Properties and Microstructure Evolution of Commercial Pure Titanium Under Electropulsing-Assisted Ultrasonic Surface Rolling Process

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Acta Metallurgica Sinica(English Letters) 2018年第12期31卷 1272-1280页

作者： Yong-Da Ye Xiao-Pei Li Zhi-Yan Sun Hai-Bo Wang Guo-Yi Tang Advanced materials Institute Graduate School at ShenzhenTsinghua University school of materials science and Engineering Tsinghua University

The effects of electropulsing-assisted ultrasonic surface rolling process on surface mechanical properties andmicrostructure evolution of commercial pure titanium were investigated. It was found that the surface mechanical prop-erties were significantly enhanced compared to traditional ultrasonic surface rolling process （USRP）, leading to smallersurface roughness and smoother morphology with fewer cracks and defects. Moreover, surface strengthened layer wasremarkably enhanced with deeper severe plastic deformation layer and higher surface hardness. Remarkable enhancementsof surface mechanical properties may be related to the gradient refined microstructure, the enhanced severe plasticdeformation layer and the accelerated formation of sub-boundaries and twins induced by coupling effects of USRP andelectropulsing. The primary intrinsic reasons for these improvements may be attributed to the thermal and athermal effectscaused by electropulsing treatment, which would accelerate dislocation mobility and atom diffusion.

关键词： Electropulsing-assisted ultrasonic surface rolling process （EP-USRP） Commercial pure titanium Roughness Hardness Microstructure evolution