Article
Chemistry, Physical
Anton Matthijs Berghuis, T. Raziman, Alexei Halpin, Shaojun Wang, Alberto G. Curto, Jaime Gomez Rivas
Summary: Using diffraction-limited ultrafast imaging techniques, the study investigated the propagation of singlet and triplet excitons in single-crystal tetracene, revealing a narrowing distribution of singlet excitons after photoexcitation. This narrowing led to a negative diffusion effect where singlet excitons migrated towards high-density regions, ultimately resulting in a distribution smaller than the laser excitation spot. Modeling of the excited-state dynamics attributed this anomalous diffusion to nonlinear triplet-triplet annihilation (TTA), which may have broad implications for studying exciton diffusion and TTA rates in semiconductors relevant to organic optoelectronics.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Nanoscience & Nanotechnology
Greta Chiaravalli, Giovanni Manfredi, Riccardo Sacco, Guglielmo Lanzani
Summary: This study focuses on the working mechanisms at the interface between the polymer and neurons, characterized through electrochemistry and mathematical modeling. The simulations demonstrate the generation of photovoltage and space charge separation in the photoexcited polymer film upon illumination, supporting the hypothesis of pseudocapacitive coupling.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Physical
Fjorela Xhyliu, Geyou Ao
Summary: This study investigated oxygen doping of SWCNTs in water using UV light irradiation, with different surface coatings having varying effects on the reaction. It was found that DNA coatings react more readily with reactive oxygen species under short-wavelength UV light, preventing oxygen doping of nanotubes. The surface coverage of coating materials plays a weaker role in controlling the reaction efficiency of oxygen doping.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Materials Science, Multidisciplinary
Roberto Rosati, Samuel Brem, Raul Perea-Causin, Robert Schmidt, Iris Niehues, Steffen Michaelis de Vasconcellos, Rudolf Bratschitsch, Ermin Malic
Summary: Monolayers of transition metal dichalcogenides have deeply bound exciton states, which are strongly affected by lattice distortions created through strain. Investigating exciton diffusion in strained tungsten disulfide (WS2) monolayers revealed a non-monotonic influence of strain on the efficiency of intervalley scattering channels. Prediction of a minimal diffusion coefficient in unstrained WS2 followed by an increase with tensile biaxial strain was confirmed by experiments.
Article
Chemistry, Multidisciplinary
Jonas D. D. Ziegler, Yeongsu Cho, Sophia Terres, Matan Menahem, Takashi Taniguchi, Kenji Watanabe, Omer Yaffe, Timothy C. C. Berkelbach, Alexey Chernikov
Summary: 2D hybrid perovskites have attracted significant attention in material research for light-harvesting and -emitting applications. In this study, a method of interfacing ultrathin sheets of perovskites with few-layer graphene and hexagonal boron nitride is demonstrated, enabling gate-tunable control of light emission and absorption. The findings reveal the emergence of both negatively and positively charged excitons, with high binding energies and excellent mobility. This research introduces the physics of interacting mixtures of optical and electrical excitations to the broad family of 2D inorganic-organic nanostructures, highlighting the potential of 2D perovskites as a promising material platform for electrically modulated light-emitters and exciton transistors.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Martin H. C. van Son, Anton M. Berghuis, Bas F. M. de Waal, Felix A. Wenzel, Klaus Kreger, Hans-Werner Schmidt, Jaime Gomez Rivas, Ghislaine Vantomme, E. W. Meijer
Summary: In this study, functionalization of C-3-symmetric carbonyl-bridged triarylamine trisamide (CBT) with oligodimethylsiloxane (oDMS) side chains was shown to lead to fully covered surfaces with aligned domains, enabling long-range exciton transport.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Physical
Chris Rehhagen, Shahnawaz Rafiq, Kyra N. Schwarz, Gregory D. Scholes, Stefan Lochbrunner
Summary: Understanding the transport mechanisms of electronic excitations in molecular systems is crucial for their application in opto-electronic devices. This study investigated the intermolecular coupling and exciton dynamics of organic nanoparticles under different preparation conditions. The results show that the intermolecular coupling can be manipulated by changing the preparation conditions, leading to variations in the exciton transfer properties.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Physics, Fluids & Plasmas
V. A. Stephanovich, W. Olchawa, E. V. Kirichenko
Summary: We investigate the influence of disorder and screening on excitons in semiconductors, such as polymeric semiconductors and van der Waals structures. We phenomenologically consider disorder using the fractional Schrodinger equation in the screened hydrogenic problem. Our main findings suggest that screening and disorder together can either destroy or enhance excitons in the semiconductor, potentially leading to their collapse in extreme cases. These effects could be relevant for understanding chaotic exciton behavior and should be taken into account in device applications where dielectric screening and disorder play important roles. Our theoretical results provide insights into the excitonic properties in semiconductors with different degrees of disorder and Coulomb interaction screenings.
Article
Multidisciplinary Sciences
Simon Raiber, Paulo E. Faria Junior, Dennis Falter, Simon Feldl, Petter Marzena, Kenji Watanabe, Takashi Taniguchi, Jaroslav Fabian, Christian Schueller
Summary: The authors investigated excitonic transitions in mono- and multi-layer WSe2 and MoSe2 with in-plane magnetic fields, attributing the oscillatory TRFE signal in multilayer samples to pseudospin quantum beats of excitons.
NATURE COMMUNICATIONS
(2022)
Article
Nanoscience & Nanotechnology
Jonas D. Ziegler, Kai-Qiang Lin, Barbara Meisinger, Xiangzhou Zhu, Manuel Kober-Czerny, Pabitra K. Nayak, Cecilia Vona, Takashi Taniguchi, Kenji Watanabe, Claudia Draxl, Henry J. Snaith, John M. Lupton, David A. Egger, Alexey Chernikov
Summary: 2D halide perovskites, with their strong interactions among electronic, optical, and vibrational excitations, hold great potential for optoelectronic applications. However, the influence of structural phase transitions on exciton properties is still not well explored. This study finds that the phase transition has no significant impact on exciton binding energy and diffusion, highlighting the unusual nature of excitons in 2D perovskites compared to commonly considered transport mechanisms.
Article
Physics, Applied
E. B. Yakimov, A. Y. Polyakov, I. V. Shchemerov, N. B. Smirnov, A. A. Vasilev, P. S. Vergeles, E. E. Yakimov, A. V. Chernykh, F. Ren, S. J. Pearton
Summary: The applicability of using Electron Beam Induced Current (EBIC) measurements on Schottky barriers to obtain the mean electron-hole pair creation energy in beta-Ga2O3 has been demonstrated. When combined with Monte Carlo simulation, this approach yielded consistent data sets for Si, GaN, and 4H-SiC, in agreement with empirical expressions proposed for various semiconductors. The method was then successfully applied to beta-Ga2O3, where complications related to hole trapping in the material were carefully addressed, resulting in a mean electron-hole pair energy formation of 15.6eV, in reasonable agreement with predicted values.
APPLIED PHYSICS LETTERS
(2021)
Article
Energy & Fuels
Friedemann D. Heinz, Maximilian Oezkent, Clara Rittmann, Florian Schindler, Martin C. Schubert, Wolfram Kwapil, Stefan Glunz
Summary: We propose a conceptual approach for localising and characterising local sites of recombination in high diffusion length semiconductors under photovoltaic field conditions. By using focused charge carrier excitation and detection, combined with scanning the specimen, we can overcome the limitation of lateral diffusion and obtain high spatial resolution photoluminescence intensity maps. The feasibility of the approach is demonstrated experimentally on silicon, a high diffusion length semiconductor.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2023)
Article
Nanoscience & Nanotechnology
Xianhua Mao, Xinxin Li, Dinglei Zheng, Xiuxiu Nie, Xiaojun Yin, Benzhang Li, Jiatao Wu, Chunmei Gao, Yuan Gao, Lei Wang
Summary: In this study, the introduction of thermocleavable side chains was shown to improve the electrical conductivity and doping efficiency of a diketopyrrolopyrrole-based copolymer, leading to enhanced thermoelectric performance. The removal of thermocleavable groups via thermal treatment significantly improved the structural arrangement and resulted in increased hole mobility, conductivity, and power factor of the material.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Physics, Applied
Guoshuai Wei, Ruiting Hao, Xiaoming Li, Yunpeng Wang, Shuiliu Fang, Jie Guo, Xiaole Ma, Yang Ren, Junbin Li, JinCheng Kong, Guowei Wang, Yingqiang Xu, Donghai Wu, Zhichuan Niu
Summary: A high-performance InAs/GaSb type-II superlattice infrared detector was fabricated and its tolerance to 1-MeV electron irradiation was characterized. The irradiation caused a significant increase in dark current density and mainly impacted the generation-recombination dark current and surface leakage current in the device.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Koloman Wagner, Zakhar A. Iakovlev, Jonas D. Ziegler, Marzia Cuccu, Takashi Taniguchi, Kenji Watanabe, Mikhail M. Glazov, Alexey Chernikov
Summary: This study demonstrates the diffusion of excitons in a monolayer semiconductor with a continuously tunable Fermi sea of free charge carriers. The light emission from tightly bound exciton states in electrically gated WSe2 monolayer is detected using microscopy. The measurements reveal a nonmonotonic dependence of the exciton diffusion coefficient on the charge carrier density.
Article
Chemistry, Physical
Zdenek Krtous, Lenka Hanykova, Ivan Krakovsky, Daniil Nikitin, Pavel Pleskunov, Ondrej Kylian, Jana Sedlarikova, Jaroslav Kousal
Summary: Plasma polymer films are typically composed of very short fragments of the precursor molecules, which limits their applicability in cases where longer molecular structures need to be retained. Plasma-assisted vapour thermal deposition (PAVTD) overcomes this limitation by using classical bulk polymers as precursors, allowing for tunable molecular structures. The PLA-like films produced in this study demonstrate the ability of PAVTD to bridge the gap between classical and plasma polymers.
Article
Multidisciplinary Sciences
Pavel Solar, Jaroslav Kousal, Jan Hanus, Katerina Skorvankova, Anna Kuzminova, Ondrej Kylian
Summary: This mechanical time-of-flight filter accurately measures the velocity of nanoparticles and allows for monitoring under various conditions.
SCIENTIFIC REPORTS
(2021)
Article
Materials Science, Coatings & Films
Zdenek Krtous, Jaroslav Kousal, Jana Sedlarikova, Zuzana Kolarova Raskova, Liliana Kucerova, Ivan Krakovsky, Jaromir Kucera, Suren Ali-Ogly, Pavel Pleskunov, Andrei Choukourov
Summary: Drug-loaded polymers with tunable composition and topology can be produced via plasma-assisted deposition of polyester thin films by thermal evaporation of polylactic acid. The released oligomers undergo hydrolysis to lactic acid over days, meeting biocompatibility demands. The films can expose micrometre-sized pores or buckling instabilities upon dissolution, enabling controlled release of antibacterial peptides for potential wound dressing and tissue-contacting devices.
SURFACE & COATINGS TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Zdenek Remes, Anna Artemenko, Egor Ukraintsev, Dhananjay K. Sharma, Maksym Buryi, Alexander Kromka, Stepan Potocky, Ondrej Szabo, Jaroslav Kulicek, Bohuslav Rezek, Ales Poruba, Julia Micova, Hua Shu Hsu
Summary: This study investigates the impact of hydrogen plasma treatment on the properties of ZnO surfaces, revealing significant alterations in surface properties before and after plasma treatment depending strongly on the electrical potential of the holder. Various analytical methods, including XPS, photoluminescence spectroscopy, AFM, and KPFM, are employed to analyze the effects on the surface properties.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2022)
Article
Nuclear Science & Technology
M. Buryi, V Babin, Z. Remes, J. Milova
Summary: The influence of X-ray irradiation on the luminescence properties and defects creation in erbium doped hydrothermally grown ZnO was investigated using various techniques. It was found that X-ray irradiation affected the photoluminescence properties of ZnO:Er and induced charge trapping and new centers creation. X-ray induced defects were identified as oxygen-based hole and electron trapping centers. The irradiation also had an impact on shallow donors in the bulk and at the surface of the ZnO nano-and microrods.
RADIATION MEASUREMENTS
(2022)
Article
Materials Science, Coatings & Films
Adela Hankova, Anna Kuzminova, Jan Hanus, Tereza Kosutova, Pavel Solar, Jaroslav Kousal, Ondrej Kylian
Summary: This study investigates the possibility of using a magnetron-based gas aggregation source for the production of mesoporous vanadium films composed of individual vanadium nanoparticles. The results show that the optimized deposition conditions allow for the production of porous nanoparticle coatings as well as coatings with columnar structures. Additionally, it is demonstrated that these coatings can be easily transformed into vanadium pentoxide films without losing their mesoporous character.
SURFACE & COATINGS TECHNOLOGY
(2022)
Article
Materials Science, Multidisciplinary
Julia Micova, Zdenek Remes, Anna Artemenko, Maksym Buryi, Miroslav Lebeda, Yu Ying Chang
Summary: A comparative study of plasma-treated Ga-doped ZnO nanorods (GZO NRs) was conducted to investigate their structural and optical properties. Various characterization methods were used to analyze the properties of plasma-treated GZO NRs. The results showed that plasma treatment can effectively purify the ZnO nanorods and alter their characteristics by changing the absorption peak intensity and signal intensity.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2022)
Article
Chemistry, Physical
Maksym Buryi, Zdenek Remes, Vladimir Babin, Sergii Chertopalov, Katerina Decka, Filip Dominec, Julia Micova, Neda Neykova
Summary: This study reports on the synthesis of Mo-doped ZnO nanorod powders by the hydrothermal growth method and the subsequent annealing or/and cold plasma modification. The influence of plasma treatment on the atomic structure and luminescence properties of ZnO:Mo structures was investigated. The results showed that plasma treatment induced the formation of new defects and affected the luminescence properties of ZnO:Mo structures.
Article
Materials Science, Multidisciplinary
Pavel Sola, Katerina Skorvankova, Anna Kuzminova, Jaroslav Kousal, Ondrej Kylian
Summary: Gas aggregation sources are valuable tools for producing nanoparticles and nano-particle films. The velocity of produced nanoparticles is a critical parameter that affects the usability of these sources and properties of the fabricated nanomaterials. A mechanical time-of-flight filter has been used to measure nanoparticle velocities and it has been found that the velocity can be controlled by process parameters such as aggregation chamber pressure and magnetron current. The velocity of nanoparticles was also found to depend on their size following a simple power law, making the filter useful not only as a velocity filter but also as a mass filter.
Article
Physics, Applied
Suren Ali-Ogly, Jaroslav Kousal, Daniil Nikitin, Pavel Pleskunov, Janus Hanus, Andrei Choukourov, Hynek Biederman
Summary: In this study, computational fluid dynamics simulations were used to analyze the flow of carrier gas in a sputter-based gas aggregation cluster source and investigate the impact of inlet and outlet geometry on gas flow and nanoparticle transport. The results showed that nanoparticles experience Brownian diffusion and drag force from the carrier gas flow, and a minimum gas velocity of 10 m/s is required to prevent loss of nanoparticles on the walls and ensure efficient nanoparticle transport.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Chemistry, Physical
Maksym Buryi, Neda Neykova, Katarina Ridzonova, Zdenek Remes, Katerina Decka, Frantisek Hajek, Anna Artemenko, Julia Micova, Lucie Landova, Ivo Jakubec
Summary: In this study, heavily Er-doped zinc oxide (ZnO) microrods with nominal compositions, ZnO:Er(2, 10, 30%), were prepared using the hydrothermal growth method. The crystallographic phases of the as grown and annealed materials were determined, confirming the presence of hexagonal Wurtzite ZnO phase in the form of hexagonal shape nanoplatelets and microrods, as well as Er2O3 phase in the form of nanosheets. Erbium incorporation into the ZnO hosts was observed to decrease with increasing doping level, leading to the formation of erbium oxide. Additionally, the influence of erbium doping and annealing on the paramagnetic shallow donor centers was studied, revealing an increase in the amount of neutral zinc vacancies upon erbium doping and a moderation of charge distribution between them upon annealing in air. Upconversion processes between the two erbium ions were observed and explained, and the surface distribution of excitonic emission centers was also investigated, showing a decrease in exciton luminescence with increasing erbium content and a stronger emission from smaller ZnO microrods.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Physical
Maksym Buryi, Vladimir Babin, Neda Neykova, Yu-Min Wang, Zdenek Remes, Katarina Ridzonova, Filip Dominec, Marina Davydova, Jan Drahokoupil, Sergii Chertopalov, Lucie Landova, Ognen Pop-Georgievski
Summary: The influence of Mo on ZnO rods in terms of electronic states, crystalline structure, morphology, phase composition, luminescence, and defects was investigated. Mo has negligible effect on the luminescence of ZnO nanoparticles, but strongly affects shallow donors in ZnO rods. Annealing in air causes a decrease in exciton and defect-related bands with increasing Mo doping level. Increasing Mo doping level from 20% to 30% results in dominating molybdates, leading to a decrease in the number of formed ZnO nanorods.
Article
Crystallography
Maksym Buryi, Amayes Medhi Gaston-Bellegarde, Jan Pejchal, Fedor Levchenko, Zdenek Remes, Katarina Ridzonova, Vladimir Babin, Sergii Chertopalov
Summary: Erbium-doped Y3Al5O12 (YAG) single crystals grown with the micro-pulling-down technique were studied. Different Er concentrations were used: 0.1%, 0.3%, and 1%. The Er3+ electron paramagnetic resonance (EPR) spectra showed changes in g tensors and Er-167 hyperfine interaction as the Er content increased, indicating a modulation of the Er-O bond length and/or Er local environment. Photoluminescence (PL) and radioluminescence (RL) spectra were complex, with overlapping Er3+ transitions and additional bands attributed to the F+ center and yttrium substituting for aluminum (Y-Al). The decay kinetics of Y-Al decreased from hundreds of nanoseconds to nanoseconds with increasing Er doping, as observed from X-ray excited decay measurements, which was discussed in relation to the EPR data.
Article
Chemistry, Physical
Maksym Buryi, Zdenek Remes, Frantisek Hajek, Karla Kuldova, Vladimir Babin, Katerina Decka, Hadi Hematian, Lucie Landova, Neda Neykova, Eva Horynova, Bohuslav Rezek
Summary: A unique set of undoped and Er-doped ZnO nanorods, grown by a hydrothermal method with the same conditions, were investigated as either 2D nanoarrays on a SiO2/ZnO substrate or free-standing nanorods on random nucleation seeds in solution. Their optoelectronic properties were characterized using various spectroscopy techniques and theoretical computations. The study showed that erbium was incorporated at a regular zinc site in the 2D arrays and as additional nucleation seeds in the free-standing nanorods. Furthermore, the deposited nanorods had a higher number of shallow donors and free carriers compared to the free-standing ones, which was attributed to their larger size and polycrystalline bunches on the random seeds in solution. Doping with Er also slowed down the excitonic emission.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Biochemistry & Molecular Biology
Chan Im, Sang Woong Kang, Jeong Yoon Choi, Jongdeok An, Julia Micova, Zdenek Remes
Summary: The transfer matrix method (TMM) was used to investigate the optical properties and performance of non-fullerene acceptor-blended polymer solar cells. It was found that the power conversion efficiency decreased with increasing active layer thickness, while the internal absorption efficiency increased. The spatial distribution of the photogenerated charge carriers became imbalanced with increasing active layer thickness, indicating a discrepancy between absorption and charge extraction.
Article
Materials Science, Multidisciplinary
Katerina Skopalova, Itana Nusa Bubanja, Dragomir Stanisavljev, Nikola Cvjeticanin, Vera Kasparkova, Eliska Dad'ova, Erika Pavlikova, Marek Koutny, Marija Gizdavic-Nikolaidis, Petr Humpolicek
Summary: This study compares the biological properties of PANI prepared by different synthesis methods and oxidizing agents, which improves its potential applications in the biomedical field.
Article
Materials Science, Multidisciplinary
Hui-Ping Li, Cai-Yan Gao, Zhi-Ping Chen, Xin-Heng Fan, Lian-Ming Yang
Summary: In this study, a novel type of D-A non-fused-ring copolymers was designed and synthesized to overcome the trade-off relationship between electrical conductivity and Seebeck coefficient in organic semiconductors. The incorporation of fluorine atoms into the polymer backbone effectively increased the ordered degree of molecular stacking and improved both the electrical conductivity and Seebeck coefficient. The bimodal orientation of polymers played a crucial role in decoupling the correlation between electrical conductivity and Seebeck coefficient.
Article
Materials Science, Multidisciplinary
Mansour A. S. Salem, Amjad Mumtaz Khan, Hatem A. M. Saleh, Khalil M. A. Qasem, Mizna Ahmed, Aadil Shafi Bhat, Abdulaziz Abdullah Qasem Ali, Younes S. A. Ghanem, Ali Alrabie, Abdel-Basit Al-Odayni, Waseem Sharaf Saeed, Basheer Al-Anesi
Summary: This research focuses on the versatile substance, polyaniline/layered double hydroxide (PANI@Nd-Co/LDH), under solvothermal conditions. A thorough analysis of its structure and morphology was conducted using various analytical methods. The findings showed that PANI@Nd-Co/LDH exhibited highly sensitive and specific fluorescence detection of Pb(II) and Al(III), outperforming other heavy metal ions. The sensor demonstrated a turn-off fluorescence response for Pb(II) ions and a turn-on fluorescence response for Al(III) ions. The minimum detectable limits (MDL) were determined to be 9.6 nM for Pb(II) and 220 nM for Al(III). PANI@Nd-Co/LDH could be easily regenerated and reused for multiple cycles. The detection mechanisms involved the inner filter effect (IFE) for Pb(II) and the chelation-enhanced fluorescence (CHEF) effect for Al(III). These results highlight the excellent potential of PANI@Nd-Co/LDH in the detection and recognition of Pb(II) and Al(III) ions.
