Article
Chemistry, Physical
Samuel H. Amsterdam, Tobin J. Marks, Mark C. Hersam
Summary: This article discusses the opportunities to manipulate the properties of two-dimensional materials using adsorbed organic molecules, including energy level alignment, surface molecular chemistry properties, defects, etc., to design new characteristics of organic-2D mixed-dimensional heterojunctions.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
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)
Review
Materials Science, Multidisciplinary
Nicolas Zorn Morales, Daniel Steffen Ruehl, Emil List-Kratochvil, Sylke Blumstengel
Summary: This review focuses on the charge and energy transfer processes and their dynamics in a specific class of van der Waals heterostructures, and demonstrates the importance of a precise knowledge of the interfacial electronic structure and provides basic design guidelines to achieve functional 2D organic/inorganic van der Waals heterostructures with final properties that can be designed by careful selection of the organic component. Understanding and controlling charge and energy transfer processes and their dynamics across the heterointerface is thereby mandatory as demonstrated with prototypical material combinations.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Review
Chemistry, Multidisciplinary
Carlo Bradac, Zai-Quan Xu, Igor Aharonovich
Summary: This article discusses the importance of van der Waals semiconductors in energy and charge transfer processes in donor-acceptor systems, as well as the role of two-dimensional materials in this field. It presents some significant experiments that deepen our understanding of transfer dynamics and looks into future challenges and opportunities.
Article
Chemistry, Multidisciplinary
Wen Wen, Wenbin Zhang, Xiaojian Wang, Qingliang Feng, Zheng Liu, Ting Yu
Summary: This study proposes a simple yet efficient strategy to develop ultrasensitive photodetectors based on heterostructures of MoS2 and polycrystalline-layered perovskites, demonstrating efficient light absorption, exciton diffusion, and interfacial charge transfer in the heterostructures with type-II band alignment.
Article
Chemistry, Multidisciplinary
Xinyi Luo, Mai He, Shijin Hou, Hong Zhou, Kai Braun, Xiaoli Zhu, Anlian Pan, Xiao Wang
Summary: Understanding and manipulating photoluminescence blinking is crucial in nano-photonics and related device applications. In this study, one-dimensional/two-dimensional heterostructures consisting of MoSe2 and CsPbBr3 were constructed. The MoSe2 in the heterostructure exhibited fluorescent blinking behavior, which was negatively correlated with the blinking in CsPbBr3 due to its super-trap states. It was concluded that the bright state of MoSe2 was due to suppressed interfacial charge transfer.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Optics
Jinping Chen, Yizhi Zhu, Heng Guo, Qiannan Cui, Zengliang Shi, Chunxiang Xu
Summary: In this study, the excitonic populations in monolayer WS2 were modulated by decorating it with Rhodamine 6G (R6G), resulting in a strong quenching of the photoluminescence (PL) and an increase in the spectral weight of trions. The type-II energy band alignment of the WS2/R6G heterointerface facilitated the photoinduced electron transfer from R6G to WS2 and hole transfer from WS2 to R6G, leading to a reduction in exciton population.
JOURNAL OF LUMINESCENCE
(2023)
Article
Chemistry, Multidisciplinary
Amir Muhammad Afzal, Muhammad Zahir Iqbal, Ghulam Dastgeer, Aqrab ul Ahmad, Byoungchoo Park
Summary: A novel vdWH FET composed of MoTe2 and PdSe2 has been studied for highly sensitive photodetection performance in the visible and near-infrared region, showing high rectification ratio, photoresponsivity, detectivity, and external quantum efficiency. The device exhibits rapid rise and decay times under incident light due to inter-TMD charge transfer transition, representing an outcome one order of magnitude faster than current literature values. These TMD-based vdWH FETs would improve photo-gating characteristics and provide a platform for highly sensitive photodetectors in the broad VNIR region.
Review
Chemistry, Physical
Ran Liu, Fakun Wang, Lixin Liu, Xiaoyu He, Jiazhen Chen, Yuan Li, Tianyou Zhai
Summary: The hybridization of two-dimensional transition metal dichalcogenides (2D TMDs) with other light-sensitive materials is an effective way to enhance the overall photoelectric performance of photodetectors. Band structure alignment at the interface of binding materials plays a crucial role in optimizing carrier transfer path and promoting charge separation rate. However, detailed summaries and reviews of band alignment engineering topics are still lacking.
Article
Chemistry, Multidisciplinary
Shixin Liu, Tian Carey, Jose Munuera, Kevin Synnatschke, Harneet Kaur, Emmet Coleman, Luke Doolan, Jonathan N. Coleman
Summary: A reliable solution-processing method is reported for fabricating heterojunction diodes with tungsten selenide nanosheets as the optical absorbing material. The obtained heterojunctions show high rectification ratios without relying on heavily doped silicon substrates and exhibit self-powered behaviors at zero bias.
Article
Chemistry, Physical
Yan Tian, Yong Cheng, Jidong Huang, Siyu Zhang, Hao Dong, Gaokai Wang, Jingren Chen, Jinliang Wu, Zhigang Yin, Xingwang Zhang
Summary: This study demonstrates the epitaxial growth of high quality large-area uniform ZrS2 films on sapphire substrates for the first time. The ZrS2 film exhibits n-type semiconductor behavior with optical phonon as the dominant scattering mechanism. The optoelectronic applications of ZrS2 films are demonstrated by fabricating photodetector devices.
Article
Nanoscience & Nanotechnology
Ranjan Kumar Behera, Leepsa Mishra, Aradhana Panigrahi, Prasana Kumar Sahoo, Manas Kumar Sarangi
Summary: Transition metal dichalcogenide based quantum dots have unique tunable photophysics and are considered as next-generation quantum materials for technology-based semiconductor applications. This article discusses the controlled synthesis of MoS2 and WS2 quantum dots and their distinctive structural, optical, and electrical characteristics. The photophysics and charge transfer kinetics between the quantum dots and a redox-active biomolecule are studied, highlighting the potential applications in advanced optoelectronic devices and future quantum technology.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Review
Chemistry, Multidisciplinary
Jiayue Han, Fakun Wang, Song Han, Wenjie Deng, Xiaoyang Du, He Yu, Jun Gou, Qi Jie Wang, Jun Wang
Summary: 2D-inorganic/organic CT photodetectors integrate 2D materials with organics to form charge transfer heterojunctions, improving the performance and functionality of photodetectors. Recent advances focus on the use of wafer-scale monocrystals and potential applications in optical biology, synapses, and machine vision.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Andrey Guskov, Sergey Lavrov, Rinat Galiev
Summary: This work demonstrates the possibility of imparting polarization-sensitive properties to two-dimensional films of graphene-like semiconductors, using the example of WSe2, by the application of ordered silver triangular nanoprisms. Additionally, these nanoprisms increase the optical sensitivity of optical detectors based on two-dimensional films by a factor of five through surface plasmon resonance.
Article
Chemistry, Multidisciplinary
Baolin Zhao, Ziyang Gan, Manuel Johnson, Emad Najafidehaghani, Tobias Rejek, Antony George, Rainer H. Fink, Andrey Turchanin, Marcus Halik
Summary: The vdW heterojunction transistor, formed by layering MoS2 monolayer crystals onto organic SAM, shows superior photoresponsivity and low dark photocurrent, demonstrating the promising strategy of hybridizing SAM with 2D materials for fabricating diverse optoelectronic devices with unique properties.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Chemistry, Physical
Ran Shi, Meng Guo, Run Long
Summary: Simulations show that mixing tin and lead in CH3NH3PbI3 can passivate the midgap state created by an interstitial iodine, reduce electron-hole wave functions overlap, and shorten pure-dephasing time. The charge carrier lifetime extends to 3.6 ns due to reduced nonradiative electron-hole recombination, which is longer than other materials. Tin-lead alloying also increases the defect formation energy, effectively enhancing defect tolerance. Overall, this study reveals the factors controlling the enhanced performance of tin-lead mixed perovskite solar cells.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Cheng Cheng, Oleg V. Prezhdo, Run Long, Wei-Hai Fang
Summary: Identifying photolysis and photothermolysis during a photochemical reaction is challenging due to the non-equilibrium and ultrafast nature of the processes. In this study, the authors use advanced ab initio molecular dynamics to investigate the photodissociation of N2O on a TiO2 surface. They establish the detailed mechanism and find that photothermolysis governs the dissociation when N2O- is short-lived, while photolysis becomes dominant as the N2O- resonance lifetime increases. The authors also demonstrate that thermal dissociation of N2O can be achieved by choosing appropriate metal dopants. Overall, this study provides a fundamental understanding of the competition and synergy between photocatalytic and photothermocatalytic dissociation of N2O and has implications for designing high-performance transition-metal oxide catalysts.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Shiyu Wang, Xin Wang, Weifeng Zhang, Xiaohu Shi, Dekui Song, Yan Zhang, Yan Zhao, Zihan Zhao, Nan Liu
Summary: Tattoo electronics, with its comfortable and imperceivable sensing, has recently gained significant attention and has been widely applied in wearable healthcare and human-machine interface. However, there is limited research on using two-dimensional materials for electronic tattoos. In this study, we report a novel electronic tattoo based on large-area Mo2C film grown by chemical vapor deposition (CVD). The Mo2C film shows good conductivity and stability. The resulting Mo2C electronic tattoo (MCET) can accurately and imperceivably acquire on-body electrophysiological signals and interface with robotics.
Article
Chemistry, Physical
Edoardo Mosconi, Asma A. Alothman, Run Long, Waldemar Kaiser, Filippo De Angelis
Summary: Controlling the chemical properties of A-site cations in 2D metal halide perovskites (MHPs) and in 2D/3D assemblies is crucial for stable and efficient optoelectronic devices. This study rationalizes the chemical interactions of different classes of organic cations in 2D MHPs, emphasizing the potential enhancement in stability through hydrogen bonding within the organic framework. This observation may lead to the design of organic cations with stronger intermolecular interactions for increased stability in MHP-based devices.
ACS ENERGY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Yan Zhang, Yangjin Lee, Weifeng Zhang, Dekui Song, Kihyun Lee, Yan Zhao, He Hao, Zihan Zhao, Shiyu Wang, Kwanpyo Kim, Nan Liu
Summary: The thin-film assisted transfer technique enables the controlled fabrication of 2D van der Waals structures with deterministic twist angles, which is crucial for twistronics.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Physical
Run Long, Ran Shi
Summary: Defects such as metal vacancies deteriorate the photoelectric properties of metal halide perovskites. Alkali metal dopants have been shown to improve the performance of mixed tin-lead perovskites. Tin vacancies produce iodine trimers and cause rapid electron-hole recombination, but alkali metal additives eliminate trap states and decelerate charge recombination, enhancing the defect tolerance of tin-lead mixed perovskites.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Lin Zhang, Hengwei Qiu, Ran Shi, Jinsong Liu, Guangliu Ran, Wenkai Zhang, Genban Sun, Run Long, Weihai Fang
Summary: This work reports the attractive performance of perovskite photoconductors based on epitaxial CsPbBr3-Pb4S3Br2 Janus nanocrystals, as well as the carrier relaxation and transfer mechanism of the heterojunction. By combining transient optical absorption and quantum dynamics simulation, it is demonstrated that the photogenerated holes on CsPbBr3 can be successfully extracted by Pb4S3Br2, with hole transfer proceeding about three times faster than energy loss and remaining hot for about 300 fs. This feature favors long-range charge separation and transport, resulting in exceptional responsivity (34.0 A W-1) and specific detectivity (1.26 x 1014 Jones) of the Janus nanocrystal photoconductors.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Haoran Lu, Run Long
Summary: The giant spin-orbit coupling (SOC) of lead significantly prolongs the charge carrier lifetimes of lead halide perovskites (LHPs). It is revealed that SOC reduces the non-radiative electron-hole recombination by decreasing the non-adiabatic coupling primarily through reshaping the electron and hole wave functions. Additionally, SOC causes spin mismatch and further decreases the non-adiabatic coupling. The presence of SOC extends the charge carrier lifetime in LHPs by approximately three times compared to the absence of SOC. This study provides fundamental understanding of how SOC minimizes non-radiative charge and energy losses in LHPs.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Hongliang Li, Meng Guo, Zhaohui Zhou, Run Long, Wei-Hai Fang
Summary: Experiments have shown that the lifetime of photoexcited carriers in alpha-Fe2O3 is significantly dependent on the excitation wavelength, but the underlying physical mechanism remains unresolved. In this study, we used nonadiabatic molecular dynamics simulation based on a well-described electronic structure of Fe2O3 to rationalize the puzzling excitation-wavelength dependence of the carrier dynamics. We found that electrons with lower-energy excitation relax fast in the conduction band, while those with higher-energy excitation undergo a slower interband relaxation before a faster intraband relaxation. This study provides insights into the excitation-wavelength dependence of carrier lifetime in Fe2O3, and offers a reference for regulating carrier dynamics in transition-metal oxides through light excitation wavelength.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Hengwei Qiu, Fu Li, Shan He, Ran Shi, Yaoyao Han, Hannikezi Abudukeremu, Lin Zhang, Yan Zhang, Song Wang, Wangyu Liu, Chao Ma, Honghua Fang, Run Long, Kaifeng Wu, Hao Zhang, Jinghong Li
Summary: This study reports the synthesis of uniform, epitaxially grown CsPbBr3/CdS Janus nanocrystal heterostructures with ultrafast charge separation across the electronically coupled interface. Each Janus nanocrystal contains a CdS domain that grows exclusively on a single {220} facet of CsPbBr3 nanocrystals. The promoted charge separation and extraction in epitaxial Janus nanocrystals leads to photoconductors with drastically improved responsivity and detectivity, which is promising for ultrasensitive photodetection.
Article
Engineering, Electrical & Electronic
Yong Lei, Run Long, Hong Li, Chenling Xiong, Chao Yang, Chenghuai Wu, Zhenxuan Yang, Fuling Tang, Wei Wang
Summary: This study demonstrated a through-wall linear-motor type flux pump for non-contact excitation of high-temperature superconducting magnets. The heating parts of the pump are located outside the cryostat to minimize heat load, and the generated heat is dissipated in the air. By using a cryogenic cooler and an insulation HTS double pancake coil, the injection of direct currents into the closed-loop without current leads was successfully achieved, verifying the feasibility and reliability of the linear-motor type flux pump for HTS magnet excitation.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2023)
Article
Chemistry, Physical
Ran Shi, Run Long
Summary: Defects like metal vacancies degrade the photoelectric properties of metal halide perovskites by serving as nonradiative recombination centers. Nonadiabatic molecular dynamics revealed that alkali metal dopants significantly enhance the performance of mixed tin-lead perovskites. Alkali dopants raise the formation energy of tin vacancies to 1 eV, resulting in decreased defect concentration. Tin vacancies facilitate the doping of alkali metals into perovskites. These vacancies generate iodine trimers that create midgap states and promote rapid electron-hole recombination. Alkali metal additives eliminate trap states, weaken nonadiabatic coupling, and slow down charge recombination with a coefficient of 5.5 compared to defective tin-lead mixed perovskites. Our research provides a theoretical model for alkali metal passivation at the atomic level, enhancing the defect tolerance of tin-lead mixed perovskites and offering valuable insights for optimizing high-performance perovskites.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Lin Zhang, Hengwei Qiu, Ran Shi, Jinsong Liu, Guangliu Ran, Wenkai Zhang, Genban Sun, Run Long, Weihai Fang
Summary: This work presents the attractive device performance of perovskite photoconductors based on epitaxial CsPbBr3-Pb4S3Br2 Janus nanocrystals. The carrier relaxation and transfer mechanism of the heterojunction is also investigated. The study demonstrates that the photogenerated holes on CsPbBr3 can be efficiently extracted by Pb4S3Br2, leading to long-range charge separation and transport, resulting in exceptional responsivity and specific detectivity.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Hua Wang, Zhaohui Zhou, Run Long, Oleg Prezhdo
Summary: In this study, ab initio quantum dynamics simulations were performed to investigate the effect α-Ga2O3 overlayers on charge recombination in Hematite photoanode. The results showed that the overlayers eliminated surface states and suppressed charge recombination, explaining the observed cathodic shift in the onset potential for water oxidation and increasing charge carrier lifetime. This work advances the understanding of the influence of surface passivation on charge recombination dynamics and provides guidance for designing novel α-Fe2O3 photoanodes.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Ran Shi, Meng Guo, Run Long
Summary: Simulations show that mixing tin with lead in CH3NH3PbI3 can passivate the midgap state created by an interstitial iodine through compressive strain and upshifted valence band maximum, reduce electron-hole wave functions overlap, and shorten pure dephasing time through high-frequency phonon modes. The significantly reduced nonradiative recombination leads to an extended charge carrier lifetime of 3.6 ns, which is an order of magnitude longer than the Ii-containing CH3NH3PbI3, over 2.5 times longer than pristine CH3NH3PbI3, and even 1.7 times longer than tin-lead mixed perovskite without I-i defects. Tin-lead alloying also increases the I-i defect formation energy, effectively enhancing defect tolerance. This study reveals the factors controlling the enhanced performance of tin-lead mixed perovskite solar cells.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
