Article
Chemistry, Physical
Ruben Canton-Vitoria, Takato Hotta, Yuri Tanuma, Ioanna K. Sideri, Nikos Tagmatarchis, Chris Ewels, Ryo Kitaura
Summary: We successfully functionalized MoS2 and WS2 with Zn-porphyrin through 1,2-dithiolane addition, creating mixed 0-2 dimensional materials. The localization of porphyrins on the basal plane of TMDs resulted in a new emission band in the NIR region, originating from charge-separated states. The optical response of excitonic species was enhanced, and sensing time-response improved after functionalization, while the stability of WS2 and MoS2 against atmospheric photodegradation was also enhanced.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Nanoscience & Nanotechnology
Tingting Guo, Xiufeng Song, Pengfei Wei, Jing Li, Yuewen Gao, Zhongzhou Cheng, Wenhan Zhou, Yu Gu, Xiang Chen, Haibo Zeng, Shengli Zhang
Summary: In this study, a MoS2/Ta2NiSe5 van der Waals heterostructure device was successfully fabricated, showing high rectification ratio and ultralow reverse bias current. The charge transfer and generation of the built-in electric field effectively suppressed dark currents. The device exhibited excellent photoelectric performance and provided an important platform for the development and application of high-performance broadband optoelectronic devices.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Physical
Shuyan Qi, Weifeng Zhang, Xiaoli Wang, Yifan Ding, Yan Zhang, Jiakang Qiu, Ting Lei, Run Long, Nan Liu
Summary: This study presents a stretchable and stable photodetector with high photoresponsivity by using an n-type dopant and assembly transfer technique with MoS2. The research found that the n-type dopant improves carrier injection efficiency and significantly enhances the photoresponsivity of MoS2 photodetectors. The photodetector also shows great durability to stretch, remaining functional after 100 stretching cycles within its limit.
Article
Chemistry, Physical
Ke Wang, Zhaoxuan Xie, Zhen Luo, Haibo Ma
Summary: The researchers have developed an automatic and efficient scheme for accurately constructing the bases for excitonic models, enabling black-box excited state structure calculations for large molecular systems. They introduced a new framework called block interaction product state (BIPS), where the bases are expressed as direct products of local states for each chromophore. Test calculations demonstrated that the BIPS framework accurately describes not only the excitation energies but also the properties of the low-lying excited states at a low computational cost.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Inorganic & Nuclear
Dooyoung Kim, Michael C. Rosko, Vinh Q. Dang, Felix N. Castellano, Thomas S. Teets
Summary: One of the main challenges in developing effective copper(I) photosensitizers is their short excited-state lifetimes. In this study, steric modifications were introduced to improve the excited-state lifetimes of these complexes, and the effects of alkyl groups on the excited-state dynamics were investigated. The results revealed that sterically encumbered complexes exhibited significantly longer excited-state lifetimes compared to the unsubstituted complex.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
P. Kumar, H. Kim, S. Tripathy, K. Watanabe, T. Taniguchi, K. S. Novoselov, D. Kotekar-Patil
Summary: Semiconducting transition metal dichalcogenides (TMDCs) are promising materials for quantum dots and spin-qubit implementation. However, the current quantum dots in TMDCs do not meet the requirements for reliable measurement of excited state spectroscopy and the g-factor. In this study, we successfully achieved electron transport through discrete energy levels in a single layer MoS2 using a dual gate geometry. By accurately measuring the ground state g-factor and observing a spin-filling sequence, we provide a useful platform for evaluating and implementing spin-valley qubits in TMDCs, thus accelerating the development of quantum systems in two-dimensional semiconducting TMDCs.
Article
Nanoscience & Nanotechnology
Caitlin R. McGranahan, Guy E. Wolfe, Alejandro Falca, David F. Watson
Summary: The study utilized N,N'-dicyclohexylcarbodiimide (DCC) coupling chemistry to synthesize heterostructures of CdSe and CdTe quantum dots in colloidal dispersions, as well as immobilizing them on metal oxide thin films. The DCC-mediated formation of amide bonds between terminal carboxylic acid and amine groups of ligands on different QDs drove the formation of heterostructures, selectively yielding dispersed or immobilized structures with programmable compositions and energetic offsets. The results showed that the carbodiimide coupling chemistry can efficiently tether colloidal QDs selectively and covalently, enabling excited-state interfacial electron transfer.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Multidisciplinary
Martin L. Kirk, David A. Shultz, Patrick Hewitt, Ju Chen, Art van der Est
Summary: Photoinduced electron spin polarization (ESP) in the ground state of luminescent materials is investigated, and the phenomenon is found to be influenced by the connecting structure and have a relatively long duration.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
M. Abith, Sabari T. C. Girisun
Summary: A MoS2-rGO nanocomposite was prepared by hydrothermal method, characterized by XRD and EDS, and studied for its optical properties, showing excellent nonlinear optical response.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Chemistry, Multidisciplinary
Guan-Yao Huang, Linhan Lin, Shuang Zhao, Wenbin Li, Xiaonan Deng, Simian Zhang, Chen Wang, Xiao-Ze Li, Yan Zhang, Hong -Hua Fang, Yixuan Zou, Peng Li, Benfeng Bai, Hong -Bo Sun, Tairan Fu
Summary: Excitons are quasi-particles composed of electron-hole pairs and play a crucial role in determining the optical properties of monolayer TMDs. Manipulating their charge states in a reversible manner remains challenging. By utilizing femtosecond-laser-driven atomic defect generation, electron transfer, and surface molecular desorption/adsorption, we have developed an all-optical approach to control the charge states of excitons in monolayer MoS2, enabling reconfigurable optical encoding.
Article
Nanoscience & Nanotechnology
Qianru Zhao, Haoran Yan, Xudong Wang, Yan Chen, Shukui Zhang, Shuaiqin Wu, Xinning Huang, Yunxiang Di, Ke Xiong, Jinhua Zeng, Hanxue Jiao, Tie Lin, Hu He, Jun Ge, Xiangjian Meng, Hong Shen, Junhao Chu, Jianlu Wang
Summary: This study demonstrates that the optical performance of 2D material-based photodetectors can be enhanced by surface acoustic wave (SAW). By manipulating the SAW, the devices exhibit significantly reduced dark current while maintaining nearly unchanged photocurrent, resulting in excellent photoresponse performance. These devices provide a promising pathway for high-performance optoelectronic applications and reveal a new possibility for acoustic devices in optoelectronics.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Piotr Kabacinski, Pietro Marabotti, Daniele Fazzi, Vasilis Petropoulos, Andrea Iudica, Patrick Serafini, Giulio Cerullo, Carlo S. S. Casari, Margherita Zavelani-Rossi
Summary: Investigated the photophysics of one-dimensional linear nanostructures and revealed their excellent mechanical, thermal, and electronic properties. Studied the excited state relaxation processes using experimental and computational methods, providing important insights into photoinduced events in low-dimensional carbon-based materials.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Younghoon Cheon, Youngsam Kim, Minsuk Park, Jehyun Oh, Eunhye Koo, Eunji Sim, Sang-Yong Ju
Summary: The study demonstrates that twisted bilayer graphene with a specific rotation angle can significantly enhance the Raman signals of copper phthalocyanine compared to single layer graphene. Reflection imaging spectroscopy and widefield Raman provide spatial and spectral information about the twisted bilayer graphene with different rotation angles and the corresponding van Hove singularities. Theoretical calculations suggest that the matching of energies between the van Hove singularities of twisted bilayer graphene and the frontier orbitals of copper phthalocyanine facilitates charge transfer processes.
Article
Optics
Muhammad Ahsan Iqbal, Xiaoliang Weng, Chenxu Kang, Nayab Arif, Kewen Wu, Wei Tang, Sichao Dai, Xueqian Fang, Houzhi Cai, Yu-Jia Zeng
Summary: Photoinduced charge-trapping is a strategy to enhance the photosensitivity of organic photodetectors, but it comes at the expense of response time. The extraction and population of triplet state excitons in TADFs is an underexplored aspect in photodetectors. By blending PBTTT-C-14 polymer with 4CzIPN TADF, it is possible to increase carrier extraction efficiency and retain electrons in the TADF triplet states.
LASER & PHOTONICS REVIEWS
(2023)
Article
Environmental Sciences
Divya Monga, Soumen Basu
Summary: This study demonstrates the fabrication of C3N5 catalyst from melamine and the preparation of MoS2/C3N5 composites with varying weight ratios using microwave-mediated method. The MC catalysts exhibit excellent photocatalytic activity in visible light for the removal of organic contaminants from water.
JOURNAL OF ENVIRONMENTAL MANAGEMENT
(2023)
Article
Chemistry, Multidisciplinary
Josefine Sprachmann, Tommy Wachsmuth, Manik Bhosale, David Burmeister, Glen J. Smales, Maximilian Schmidt, Zdravko Kochovski, Niklas Grabicki, Robin Wessling, Emil J. W. List-Kratochvil, Birgit Esser, Oliver Dumele
Summary: Despite being unstable, 4n pi systems have gained attention for their unique optical and electronic properties. The first antiaromatic framework materials were synthesized and a series of highly crystalline and porous COFs based on DBP were obtained. These antiaromatic COFs show potential applications in positive electrode materials for Li-organic batteries and exhibit photoconductivity upon visible light irradiation.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Materials Science, Multidisciplinary
Alberto Taffelli, Giovanni Ligorio, Lucio Pancheri, Alberto Quaranta, Riccardo Ceccato, Andrea Chiappini, Marco Vittorio Nardi, Emil J. W. List-Kratochvil, Sandra Dire
Summary: This study optimizes a sol-gel synthesis method for the fabrication of MoS2 films, enabling the deposition of large area MoS2 films on different substrates. The films exhibit desired chemical and physical properties expected for 2D-MoS2 and show uniformity across the entire film area. Photodetector devices made using this fabrication method demonstrate responsivity values of few mA/W in the NUV-VIS-NIR spectrum, expanding the spectral response range of MoS2-based photodetectors previously reported. Despite the influence of residual electronic defects on the device response time and light-to-dark current ratio, this work presents a scalable and versatile process for fabricating 2D-MoS2 and photodetectors based on it.
Article
Materials Science, Multidisciplinary
Sofie Vogt, Clemens Petersen, Max Kneiss, Daniel Splith, Thorsten Schultz, Holger von Wenckstern, Norbert Koch, Marius Grundmann
Summary: This study presents the structural and electrical properties of undoped and doped alpha-Ga2O3 thin films grown on m-plane sapphire. An undoped alpha-Ga2O3 buffer layer was introduced to improve crystal quality and stabilize the alpha-phase at lower substrate temperatures. Donor doping with tin and germanium achieved high electron mobilities. Suitable annealing temperature for ohmic Ti/Al/Au layer stacks was identified, while high annealing temperatures deteriorated the electrical properties of the thin films, indicating the need for low temperature contacting procedures for alpha-Ga2O3-based devices.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Lennart Frohloff, Fengshuo Zu, Dongguen Shin, Norbert Koch
Summary: One promising approach for fabricating high-performance solar cells is to combine metal halide perovskites with organic semiconductors. Proper energy level alignment at device interfaces is crucial for achieving high device performance. In this study, we investigate the interface between a triple cation perovskite and an electron acceptor molecule and find that charge transfer induces a band bending effect, altering the charge extraction barriers. Additionally, we observe reversible shifts in the energy levels of the organic layer under white light illumination, indicating an electrostatic origin of this phenomenon.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2023)
Article
Physics, Applied
Ross Warren, Paul W. M. Blom, Norbert Koch
Summary: This study measures the dielectric constant in thin films of regioregular poly(3-hexylthiophen-2,5-diyl) (P3HT) using impedance spectroscopy. The results show that molecular doping has a considerable impact on the dielectric constant.
APPLIED PHYSICS LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Paul Haensch, Selen Solak, Hyung Seok Choi, Yohan Kim, Giovanni Ligorio, Manuel Gensler, Jiyong Kim, Christine Boeffel, Emil J. W. List-Kratochvil, Felix Hermerschmidt
Summary: Quantum dot (QD) materials are being increasingly used in display applications due to their high color purity and fluorescence quantum yield, resulting in devices with higher brightness and efficiency. In this study, a zinc selenide-based blue QD material was synthesized and air-fabricated into light-emitting diodes (LEDs) and single-carrier devices. The QD-LED devices showed pure deep blue/purple fluorescence emission with a high photoluminescence quantum yield of 78%. By utilizing different electron transport layers, the devices achieved maximum luminance values of 6200 cd m(-2) and 3000 cd m(-2) with turn-on voltages of 3.5 V and 3 V, respectively. This study demonstrates, for the first time, the air-fabrication of ZnSe-based QD-LEDs, opening up possibilities for large-scale display applications and high-performance printed electronics.
Article
Materials Science, Multidisciplinary
Thorsten Schultz, Peer Baermann, Elena Longhi, Rahul Meena, Yves Geerts, Yury Gogotsi, Stephen Barlow, Seth R. Marder, Tristan Petit, Norbert Koch
Summary: Two-dimensional MXenes, especially Ti(3)C(2)Tx, have promising properties for various applications. The work function of MXenes is crucial for energy level alignment, and methods to control the work function should be developed.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Ahmed E. Mansour, Ross Warren, Dominique Lungwitz, Michael Forster, Ullrich Scherf, Andreas Opitz, Moritz Malischewski, Norbert Koch
Summary: This study presents a simple method to enhance the oxidation strength of molecular dopants for organic semiconductors, while reducing diffusion in polymer hosts. Experimental results demonstrate higher efficiency of the new dopant complex compared to traditional molecular dopants.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Materials Science, Multidisciplinary
Johannes Mueller, Max Heyl, Thorsten Schultz, Kristiane Elsner, Marcel Schloz, Steffen Ruehl, Helene Seiler, Norbert Koch, Emil J. W. List-Kratochvil, Christoph T. Koch
Summary: 4D scanning transmission electron microscopy (4D-STEM) is a powerful technique that can characterize electron-transparent samples with high spatial resolution. By rastering an electron beam over a sample area and acquiring transmission diffraction patterns, 4D-STEM can provide detailed information about the atomic structure, crystallinity, orientation, and other properties of the sample. It can be used in scanning electron microscopes (SEMs) to study 2D materials and vdWH, with their inherently thin thickness. A unique 4D-STEM-in-SEM system is applied to reveal the single crystallinity of MoS2 exfoliated with gold-mediation and determine the crystal orientation and coverage of both components in a C60/MoS2 vdWH.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Sarah Gruetzmacher, Max Heyl, Marco Vittorio Nardi, Norbert Koch, Emil J. W. List-Kratochvil, Giovanni Ligorio
Summary: 2D transition metal dichalcogenides (TMDCs) are semiconductors with potential for optoelectronic applications, and their properties can be altered by chemically engineering the substrate surface. This study demonstrates local doping and adjustment of the electronic and optical properties of TMDCs (WSe2 and MoS2) by decorating the substrate with self-assembled monolayers (SAMs) with different molecular dipoles and dielectric constants. The interaction between SAMs and TMDCs leads to changes in the electronic band gap width, which can be predicted using the Schottky-Mott rule and knowledge of the dielectric screening effects. Understanding these effects allows for accurate prediction of TMDCs behavior for device design.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Fengshuo Zu, Dongguen Shin, Emilio Gutierrez-Partida, Martin Stolterfoht, Patrick Amsalem, Norbert Koch
Summary: The electronic properties of metal halide perovskites (MHPs) are crucial for optimal optoelectronic devices, but photoelectron spectroscopy (PES) measurements can be complex due to charge selective junctions and high-energy photons causing energy level realignment. Bremsstrahlung from twin-anode lab-sources can induce sizable shifts in core levels, whereas monochromatized X-ray lab-sources have minimal effects. These findings aim to enhance the reliability of PES measurements for obtaining accurate MHP electronic property information.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Nanoscience & Nanotechnology
Alberto Taffelli, Max Heyl, Matteo Favaro, Sandra Dire, Lucio Pancheri, Emil J. W. List-Kratochvil, Alberto Quaranta, Giovanni Ligorio
Summary: Two-dimensional transition metal dichalcogenides (TMDCs) show great potential as semiconductors for optoelectronic applications in the ultraviolet-visible spectral range, but their characteristics under x-rays have not been characterized yet. This paper demonstrates the use of TMDCs as direct x-ray detectors, and improves the x-ray photoresponse by coupling with a polymer film integrated with a scintillator. This may pave the way for the production of ultrathin real-time dosimeters for in vivo applications.
Article
Chemistry, Multidisciplinary
Vincent R. F. Schroeder, Nicolas Fratzscher, Florian Mathies, Edgar R. Nandayapa, Felix Hermerschmidt, Eva L. Unger, Emil J. W. List-Kratochvil
Summary: We demonstrate the upscaling of inkjet-printed metal halide perovskite light-emitting diodes by optimizing the drying process with an airblade-like slit nozzle. This results in large, continuous perovskite layers in light-emitting diodes with an active area up to 1600 mm(2).
Article
Chemistry, Multidisciplinary
David Burmeister, Alberto Eljarrat, Michele Guerrini, Eva Rock, Julian Plaickner, Christoph T. Koch, Natalie T. Banerji, Caterina Cocchi, Emil J. W. List-Kratochvil, Michael J. Bojdys
Summary: Graphitic carbon nitrides are promising materials for overcoming the limitations of 0D molecular and 1D polymer semiconductors due to their covalently-bonded, layered, and crystalline structure. This study investigates the structural, vibrational, electronic, and transport properties of poly(triazine-imide) (PTI) derivatives with and without intercalated ions. It is found that PTI nano-crystals exhibit high charge carrier density and THz conductivity, but the electroluminescence from the pi-pi* transition is quenched, limiting their use in electroluminescent devices. Macroscopic charge transport in PTI films is also hindered by disorder at crystal-crystal interfaces.