Article
Materials Science, Multidisciplinary
Qinglin Wei, Xinglin Wen, Junchao Hu, Yingying Chen, Zeyi Liu, Tinghao Lin, Dehui Li
Summary: Recently, it has been discovered that interlayer excitons can be robustly formed in transition metal dichalcogenides/two-dimensional perovskite heterostructures, and their performance can be enhanced by controlling the interlayer coupling. By tuning the height and diameter of pillars, the interlayer coupling can be further engineered. Additionally, the symmetry breaking of monolayer WSe2 can lead to the appearance of an additional triplet interlayer exciton and induce an anisotropic response.
SCIENCE CHINA-MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
P. Martinez-Merino, R. Alcantara, J. Navas
Summary: This study explores the thermophysical properties of nanofluids based on one-dimensional WSe2 nanostructures and investigates their feasibility as heat transfer fluids in concentrating solar power plants. The results show that these nanofluids exhibit enhanced thermal conductivity and heat transfer efficiency, indicating their potential for improving the thermal efficiency of solar power plants.
MATERIALS TODAY CHEMISTRY
(2023)
Article
Nanoscience & Nanotechnology
Lily J. Stanley, Hsun-Jen Chuang, Zhixian Zhou, Michael R. Koehler, Jiaqiang Yan, David G. Mandrus, Dragana Popovic
Summary: The fabrication of hBN-encapsulated multiterminal WSe2 devices with 2D/2D low-temperature Ohmic contacts allows for investigation of the 2D metal-insulator transition. The devices exhibit Ohmic behavior down to 0.25 K and enable accurate determination of carrier density. Measurements show scaling behavior consistent with a metal-insulator quantum phase transition driven by electron-electron interactions and disorder-induced local magnetic moments.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Materials Science, Multidisciplinary
Ary Anggara Wibowo, Mike Tebyetekerwa, Anh Dinh Bui, Thien N. Truong, Sandra Saji, Felipe Kremer, Zhongshu Yang, Zongyou Yin, Yuerui Lu, Daniel Macdonald, Hieu T. Nguyen
Summary: In this study, a method for growing large-area, high-quality MoSe2 monolayers and MoSe2-WSe2/WSe2-MoSe2 lateral heterostructures using molten salt-based chemical vapor deposition (CVD) is reported. The effects of different catalysts on the growth and optoelectronic quality of the materials are investigated, and it is found that molten salt catalysts support high-quality growth of MoSe2 monolayers and WSe2-MoSe2 lateral heterostructures.
ADVANCED MATERIALS TECHNOLOGIES
(2023)
Article
Chemistry, Multidisciplinary
Simrjit Singh, Weiyi Gong, Christopher E. Stevens, Jin Hou, Aditya Singh, Huiqin Zhang, Surendra B. Anantharaman, Aditya D. Mohite, Joshua R. Hendrickson, Qimin Yan, Deep Jariwala
Summary: This article investigates the interlayer exciton phenomenon in two-dimensional heterostructures, and demonstrates the observation of helicity-resolved interlayer excitons through spin-valley layer coupling. This method does not require a specific geometric arrangement, such as twist angle or thermal annealing. The research shows that there are spin-valley-dependent optical selection rules in two-dimensional perovskites and monolayer transition metal dichalcogenides.
Article
Chemistry, Multidisciplinary
Suchithra Padmajan Sasikala, Prem Prabhakaran, Sambath Baskaran, Jun Tae Kim, Gang San Lee, Yeo Hoon Yoon, Hee Jae Choi, Jin Goo Kim, Jun Beom Kim, Sang Ouk Kim
Summary: This study presents a highly efficient and scalable solution method for simultaneously exfoliating and functionalizing WSe2, a p-type 2D semiconductor with unique optoelectrical properties. The method utilizes the non-covalent interaction between mercapto-group and bulk WSe2. Single and few-layer 2H phase pure WSe2 sheets with minimal basal plane defects are successfully produced in a water-ethanol mixture. The obtained WSe2 dispersion remains stable even at high concentrations and exhibits high colloidal stability.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Materials Science, Multidisciplinary
Esma Ugur, Erkan Aydin, Michele De Bastiani, George T. Harrison, Bumin K. Yildirim, Sam Teale, Bin Chen, Jiang Liu, Mingcong Wang, Akmaral Seitkhan, Maxime Babics, Anand S. Subbiah, Ahmed Ali Said, Randi Azmi, Atteq Ur Rehman, Thomas G. Allen, Philip Schulz, Edward H. Sargent, Frederic Laquai, Stefaan De Wolf
Summary: By tuninging the dimensionality of 2D perovskites, an improved passivation at the interface and enhanced hole extraction can be achieved, resulting in improved performance and higher photocurrent in perovskite solar cells.
Article
Chemistry, Multidisciplinary
Xing Xie, Junnan Ding, Biao Wu, Haihong Zheng, Shaofei Li, Chang-Tian Wang, Jun He, Zongwen Liu, Jian-Tao Wang, Yanping Liu
Summary: This study presents a dynamic tuning method for twisted WSe2/WSe2 homobilayers and demonstrates the powerful tuning of interlayer coupling. It is found that the introduction of a moire superlattice leads to hybridized excitons and different pressure-evolution exciton behaviors compared to natural bilayers.
Article
Chemistry, Multidisciplinary
Lene Gammelgaard, Patrick R. Whelan, Timothy J. Booth, Peter Boggild
Summary: This study used AFM to investigate the long-term evolution of oxidative defects of WSe2 in ambient conditions over 75 months, finding that step-edges with high phase-contrast degrade after medium- to long-term exposure. The phase-contrast showed correlation with sun-hours, and storing in darkness slowed down the evolution process.
Article
Chemistry, Physical
Juwon Oh, Hung-Tzu Chang, Christopher T. Chen, Shaul Aloni, Adam Schwartzberg, Stephen R. Leone
Summary: Carrier and phonon dynamics in a multilayer WSe2 film were investigated using extreme ultraviolet (XUV) transient absorption (TA) spectroscopy. The results showed that XUV transient absorption directly revealed the occupation of optically excited holes and phonon-induced band renormalizations. Hole-induced XUV transient absorption was observed below the W O3 edge, while the signals at the Se M4,5 edges were dominated by phonon dynamics. The obtained relaxation and recombination times for holes and heating time for phonons provided valuable insights into the electron-phonon dynamics.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Zilong Wang, Patrick Altmann, Christoph Gadermaier, Yating Yang, Wei Li, Lavinia Ghirardini, Chiara Trovatello, Marco Finazzi, Lamberto Duo, Michele Celebrano, Run Long, Deji Akinwande, Oleg Prezhdo, Giulio Cerullo, Stefano Dal Conte
Summary: Experimental and quantum dynamics simulations indicate that charge separation in MoSe2/WSe2 heterostructures is ultrafast and temperature-independent, while recombination accelerates significantly with temperature. Charge separation is temperature-independent due to its barrierless nature, involvement of dense acceptor states, and promotion by higher-frequency vibrations, while the strong temperature dependence of recombination arises from modulation of indirect-to-direct bandgap by low-frequency motions.
Article
Materials Science, Multidisciplinary
Jiacheng Sun, Zhu Lin, Xiaofang Jia, Huiting Li, Cheng Song, Feng Pan, Lu Fang, Junying Zhang, Yuyan Wang
Summary: Transition metal dichalcogenides (TMDs) with tunable energy bandgap and strong light-matter interaction are potential candidates for next-generation photodetectors. A controllable n-doping technique for 2D TMDs materials by annealing under NH3 flow is demonstrated, which significantly improves the optoelectronic performance of the devices. The doping effect is attributed to the physical and chemical adsorption of NH3 and the formation of isolated sulfur vacancies, confirmed by atomic-scale characterization and density functional theory calculations. The fabricated WS2 photodetector exhibits high responsivity, external quantum efficiency, and specific detectivity, indicating its great potential in sensitive and power-efficient photodetection. Our results provide an effective method for controllable n-doping of 2D materials, aiming to fabricate high-performance 2D photodetectors.
MATERIALS TODAY PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Yu Liang, Bo-Han Li, Ziling Li, Guanhua Zhang, Julong Sun, Chuanyao Zhou, Youtian Tao, Yu Ye, Zefeng Ren, Xueming Yang
Summary: This study investigated the ultrafast carrier dynamics of two-dimensional molybdenum disulfide (MoS2) flakes using femtosecond time-resolved micro-area photoelectron spectroscopy and photoemission electron microscopy. Spatial heterogeneity and defect effects were observed, with defects significantly shortening charge carrier lifetime while acting as recombination centers. Three relaxation processes were identified in the photoelectron intensity dynamics, with different rates influenced by defect density and bulk electron transportation. The results deepen the understanding of interfacial carrier dynamics and defect effects on charge carrier lifetime in MoS2 materials.
MATERIALS TODAY PHYSICS
(2021)
Review
Chemistry, Multidisciplinary
Sugata Chowdhury, Albert F. Rigosi, Heather M. Hill, Patrick Vora, Angela R. Hight Walker, Francesca Tavazza
Summary: This review focuses on computational efforts and advancements in the field of charge density waves (CDWs) in two-dimensional (2D) materials. It covers various subtopics such as computational techniques, resulting atomic structures, electron-phonon interaction effects, confinement and dimensionality effects, and future outlook.
Article
Chemistry, Multidisciplinary
Haiyang Liu, Deyi Fu, Xu Li, Junbo Han, Xiaodie Chen, Xuefeng Wu, Baofan Sun, Weiqing Tang, Congming Ke, Yaping Wu, Zhiming Wu, Junyong Kang
Summary: This study proposes a phase engineering strategy to enhance valley splitting in monolayer WSe2 by modifying the intrinsic lattice structure, and further reveals that valley splitting in hybrid H and T phase WSe2 can be tuned by T phase concentration. The enhanced valley splitting is mainly attributed to exchange interaction of H phase WSe2 with the local magnetic moments induced by the T phase, providing a convenient solution for lifting the valley degeneracy of two-dimensional materials.
Review
Chemistry, Physical
Tianyue Wang, Wenqiu Deng, Jiupeng Cao, Feng Yan
Summary: Metal halide perovskite solar cells (PSCs) are promising next-generation photovoltaic technologies with low-cost fabrication, solution processability, and superior optoelectronic properties. However, commercialization still faces challenges and advanced heterojunction design is crucial for improving device performance.
ADVANCED ENERGY MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Dengrong Sun, Lok Wing Wong, Hok Yin Wong, Ka Hei Lai, Lin Ye, Xinyao Xv, Thuc Hue Ly, Qingming Deng, Jiong Zhao
Summary: The atomic structure of multivariate metal-organic frameworks (MTV-MOFs) was visualized using the iDPC-STEM technique, guiding the design of bulk MOFs for efficient oxygen evolution reaction (OER). Incorporating Fe3+ or 2-aminoterephthalate (ATA) into Ni-BDC weakened the coordination bonds, allowing for selective cleavage via mild heat treatment to generate coordinatively unsaturated metal sites, conductive Ni@C, and hierarchical porous structure. The defective MOFs exhibited excellent OER activity, with current densities of 10 and 100 mA cm(-2) achieved at small overpotentials of 286 mV and 365 mV, respectively, surpassing commercial RuO2 catalyst and most bulk MOFs.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Hok-Leung Loi, Jiupeng Cao, Chun-Ki Liu, Yang Xu, Mitch Guijun Li, Feng Yan
Summary: This study reports phototransistors based on mixed Sn/Pb perovskites, which exhibit high sensitivity in a broadband spectrum due to the optimized interface properties and compositional gradient in the perovskite channel.
Article
Chemistry, Physical
Hui Liu, Lu Zhu, Hong Zhang, Xinjun He, Feng Yan, Kam Sing Wong, Wallace C. H. Choy
Summary: In this study, a tailored tin-lead perovskite structure was developed by using tin thiocyanate to form a double-sided surface-preferred distribution in the perovskite. This significantly improved the film morphology and antioxidation ability, resulting in high-performance near-infrared photodetectors.
ACS ENERGY LETTERS
(2023)
Article
Multidisciplinary Sciences
Jiajun Song, Hong Liu, Zeyu Zhao, Xuyun Guo, Chun-ki Liu, Sophie Griggs, Adam Marks, Ye Zhu, Helen Ka-wai Law, Iain McCulloch, Feng Yan
Summary: In this study, electrochemical transistors (ECTs) based on highly oriented two-dimensional conjugated metal-organic frameworks (2D c-MOFs) are demonstrated. The 2D c-MOFs films exhibit ion-conductive vertical nanopores, enabling efficient ion transfer and high volumetric capacitance. The ECTs show fast speeds and ultrahigh transconductance, and are successfully used for wearable on-skin recording of electrocardiogram (ECG) signals.
Article
Nanoscience & Nanotechnology
Hok Yin Wong, Lok Wing Wong, Chi Sing Tsang, Zhangyuan Yan, Xuming Zhang, Jiong Zhao, Thuc Hue Ly
Summary: Atmospheric water harvesting (AWH) is a possible solution for the water crisis and the key process has been applied in commercial dehumidifiers. A superhydrophobic surface technique, induced by coalescence-induced jumping, is proposed to enhance the AWH process. In this study, a simple and low-cost approach for superhydrophobic surface engineering through alkaline oxidation of copper is reported, which provides medium-sized microflower structures that act as nucleation sites and promoters for the AWH process. Machine learning computer vision techniques are also applied to optimize the AWH structure for droplet dynamic analysis on a micrometer scale. Overall, the alkaline surface oxidation and medium-scale microstructures offer great opportunities for superhydrophobic surfaces in AWH applications.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Review
Chemistry, Multidisciplinary
Jiajun Song, Hong Liu, Zeyu Zhao, Peng Lin, Feng Yan
Summary: Flexible and stretchable biosensors are increasingly utilized for acquiring high-fidelity signals in emerging applications. Organic thin film transistors (OTFTs) are ideal candidates for flexible and stretchable biosensing due to their soft nature, amplification function, biocompatibility, functionalization ease, low cost, and device diversity. This review provides a comprehensive overview of the advancements in flexible-OTFT-based biosensors, discussing their features, functionalization strategies, applications in wearable, implantable, and portable electronics, as well as neuromorphic biointerfaces. Special attention is given to emerging stretchable organic transistors and their engineering routes for achieving stretchability, along with their implementations in e-skin and smart textiles. The remaining challenges and future opportunities in this field are also summarized.
ADVANCED MATERIALS
(2023)
Article
Physics, Applied
Yuqian Zhao, Feng Guo, Sin-Yi Pang, Weng Fu Io, Lok-Wing Wong, Jiong Zhao, Jianhua Hao
Summary: The anisotropic Raman response of ultrathin black phosphorus (BP) transferred to an oxide dielectric substrate is investigated by utilizing a piezoelectric actuator to perform biaxial strain engineering. The strained Raman response is related to the variations of bond angle and bond length in BP, and biaxial strain modulation can change the anisotropic dispersion of BP.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Quoc Huy Thi, Ping Man, Haijun Liu, Lingli Huang, Xin Chen, Chun-Sing Lee, Jiong Zhao, Qingming Deng, Saba Saeed, Thuc Hue Ly
Summary: Low temperature and high humidity conditions degrade the performance of solid-state lubricants by enhancing interlayer friction due to the presence of liquid water layer attached to the van der Waals (vdW) atomic layers. However, this study reveals unexpected ultralow friction between 2D ice and 2D molybdenum disulfides (MoS2) using low temperature in situ atomic force microscopy (AFM) and friction force microscopy (FFM). The friction of MoS2 and 2D ice is reduced by more than 30% compared to bare MoS2 and rigid surface.
Article
Energy & Fuels
Xianglin Chen, Ya Li, Jiupeng Cao, Haoyu Chen, Bingxu Liu, Jiankai Xie, Yuting Shu, Fangfang Wang, Aifei Wang, Jingjin Dong, Tianshi Qin
Summary: By introducing a multifunctional zinc ethylphenyl dithiocarbamate (Ze) additive, the crystallization process of tin-based perovskite is tuned and the oxidation of Sn2+ is suppressed, while the defects are effectively passivated and nonradiative recombination is reduced. As a result, the Ze-modified solar cells exhibit an efficiency of 4.64% along with excellent long-term stability.
Article
Engineering, Electrical & Electronic
Ya Li, Suhao Yan, Jiupeng Cao, Haoyu Chen, Bingxu Liu, Jiankai Xie, Yuting Shu, Fangfang Wang, Aifei Wang, Jingjin Dong, Tianshi Qin
Summary: Flexible Sn-Pb mixed perovskite solar cells (PSCs) with in situ synthesized cross-linking polymer using N,N-dimethyl acrylamide (DMAA) as scaffold exhibited reduced defects and improved crystallization, resulting in an efficiency of 15.44%. These flexible PSCs also demonstrated excellent bending durability, retaining over 80% of the original efficiency after 5000 bending cycles at a radius of 5 mm.
NPJ FLEXIBLE ELECTRONICS
(2023)
Review
Chemistry, Multidisciplinary
Ping Man, Lingli Huang, Jiong Zhao, Thuc Hue Ly
Summary: Two-dimensional (2D) ferroics, including ferroelectric, ferromagnetic, and ferroelastic materials, have gained significant attention due to their unique physical properties and potential applications. Recent theoretical predictions have identified various 2D ferroic phases, including multiferroics and newly discovered ferrovalleytronics/ferrotoroidics, even at the atomic scale. These predictions have been experimentally confirmed, and the manipulation of ferroic phases in 2D materials through stacking, doping, and defects has also been demonstrated. The remarkable ferroic ordering in 2D materials holds great promise for high-density memory devices, energy conversion devices, and sensing applications. This comprehensive review explores the recent advances in 2D ferroic phases, focusing on the chemistry and structural origins of these properties, as well as discussing their potential applications in information storage, optoelectronics, and sensing. Furthermore, future pathways for research and development in 2D ferroics are envisioned, aiming to provide a comprehensive understanding of this field and facilitate further exploration of new materials and physical phenomena that will have a significant impact on future functional materials and devices.
Article
Chemistry, Multidisciplinary
Xu Wen Zhao, Hon Fai Wong, Yu Kuai Liu, Sheung Mei Ng, Min Gan, Lok Wing Wong, Jiong Zhao, Zongrong Wang, Wang Fai Cheng, Chuanwei Huang, Linfeng Fei, Chee Leung Mak, Chi Wah Leung
Summary: This study demonstrates the regulation of negative exchange bias in ferromagnetic/antiferromagnetic manganite bilayers using the field-effect device geometry with a ferroelectric copolymer as a gating layer. The low-voltage pulse modulation of exchange bias is achieved by creating/annihilating oxygen vacancies in the antiferromagnetic layer. This research highlights the potential for low-voltage pulse control of physical properties in antiferromagnetic perovskite oxide insulators.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Nanoscience & Nanotechnology
Yanyu Lin, Zhangyuan Yan, Chi Shing Tsang, Lok Wing Wong, Xiaodong Zheng, Fangyuan Zheng, Jiong Zhao, Ke Chen
Summary: Recent advancements in TEM have enabled the study of atomic structures at unprecedented small scales. However, accurately detecting atomic positions from TEM images remains challenging, especially in the presence of background noise or contamination. To overcome this, AtomID-Net, a deep neural network model, is introduced for atomic detection from low-SNR experimental images in STEM. The model, trained on real images, achieves robust and efficient detection even in the presence of noise and contamination, outperforming existing peak-finding algorithms.
Article
Chemistry, Multidisciplinary
Jing Zhuang, Chunki Liu, Bochun Kang, Haiyang Cheng, Mingchao Xiao, Li Li, Feng Yan
Summary: This study presents a convenient and effective approach for improving the performance of blade-coated perovskite solar cells (PSCs). By dissolving a novel modifier in acetonitrile, the perovskite surface can be reconstructed in hundreds of milliseconds, leading to enhanced device performance.
ADVANCED MATERIALS
(2023)
