Article
Materials Science, Multidisciplinary
Thomas Garm Pedersen
Summary: Excitons in two dimensions and other low-dimensional semiconductors show deviation from simple Wannier model due to nonlocal dielectric screening. A Kratzer model, incorporating a repulsive core potential, has been proposed as an analytically solvable model for nonhydrogenic excitons. This study utilizes this model to describe static and dynamic Stark effects in low-dimensional semiconductors, providing an exact formula for exciton polarizability and analytical oscillator strengths for analyzing dynamic Stark effect in different dimensions and materials.
Article
Optics
Peter Schnauber, Jan Grosse, Arsenty Kaganskiy, Maximilian Ott, Pavel Anikin, Ronny Schmidt, Sven Rodt, Stephan Reitzenstein
Summary: The deterministic integration of self-assembled quantum dots in waveguide structures has been achieved using in situ electron beam lithography. Spectral fine-tuning of the QDs has been achieved by applying external bias voltages, with the potential to enable the scalable fabrication of integrated quantum photonic circuits in the future.
Article
Chemistry, Multidisciplinary
Qinyuan Jiang, Run Li, Fei Wang, Xiaofei Shi, Fengxiang Chen, Ya Huang, Baoshun Wang, Wenshuo Zhang, Xueke Wu, Fei Wei, Rufan Zhang
Summary: This article presents suspended carbon nanotube networks (SCNTNs) as high-performance airflow sensors, achieving a short response time, high sensitivity, small detection threshold, and wide detection range, surpassing most existing airflow sensors.
ADVANCED MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Taishi Nishihara, Akira Takakura, Keisuke Matsui, Kenichiro Itami, Yuhei Miyauchi
Summary: Researchers have statistically verified the chirality distribution of 413 individual as-grown single-walled carbon nanotubes using broadband Rayleigh spectroscopy. The results show an increasing trend in chirality distribution with a distinct anomaly at approximately 20 degrees, which can be explained by the influence of armchair-shaped site configurations at the catalyst-nanotube interface growth rate.
Article
Chemistry, Physical
Kensuke Saito, Tomonari Koishi, Jianfeng Bao, Wataru Norimatsu, Michiko Kusunoki, Hideo Kishida, Takeshi Koyama
Summary: This study reveals that bilayer graphene exhibits longer and stronger photoluminescence compared to monolayer graphene in femtosecond excitation, with a higher carrier temperature. This suggests that bilayer graphene has superior light-emitting properties and potential for graphene-based light-emitting devices.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Min-Ken Li, Adnan Riaz, Martina Wederhake, Karin Fink, Avishek Saha, Simone Dehm, Xiaowei He, Friedrich Schoeppler, Manfred M. Kappes, Han Htoon, Valentin N. Popov, Stephen K. Doom, Tobias Hertel, Frank Hennrich, Ralph Krupke
Summary: This work demonstrates that electroluminescence excitation is selective towards neutral defect-state configurations with the lowest transition energy, which, combined with gate control, leads to high spectral purity.
Article
Chemistry, Physical
Stefano Dal Forno, Natsumi Komatsu, Michael Wais, Ali Mojibpour, Indrajit Wadgaonkar, Saunab Ghosh, Yohei Yomogida, Kazuhiro Yanagi, Karsten Held, Junichiro Kono, Marco Battiato
Summary: The study investigates excitonic effects in 1D semiconductors, revealing that the Sommerfeld factor is less than 1 in such systems while it is greater than 1 in 2D and 3D systems. Using a theoretical model, the absorption spectra of carbon nanotube films were fitted, uncovering the mechanism behind background absorption.
Article
Chemistry, Multidisciplinary
Song Zhu, Wenkai Li, Shengjie Yu, Natsumi Komatsu, Andrey Baydin, Fakun Wang, Fangyuan Sun, Chongwu Wang, Wenduo Chen, Chuan Seng Tan, Houkun Liang, Yohei Yomogida, Kazuhiro Yanagi, Junichiro Kono, Qi Jie Wang
Summary: Aligned and type-separated (semiconducting and metallic) carbon nanotubes films were synthesized and studied for their polarization-dependent third-harmonic generation (THG) processes in a broad spectral range. These films exhibited strong wavelength-dependent and intense THG signals, enhanced by exciton resonances, confirming their macroscopically 1D nature. The findings suggest potential applications of these films in various nonlinear photonic devices. Evaluation: 8/10.
ADVANCED MATERIALS
(2023)
Article
Physics, Applied
Ju Zhou, Tian-Yi Cai, Sheng Ju
Summary: This paper investigates the evolution of the quasiparticle electronic structure, exciton, and optical properties of two-dimensional Hittorf's phosphorene under an electric field. The results show that the exciton energy and optical absorption edge of Hittorf's phosphorene remain almost unchanged at low applied electric fields, but significantly decrease when the electric field exceeds 0.1 V/??.
PHYSICAL REVIEW APPLIED
(2022)
Article
Engineering, Chemical
Mitun Chandra Bhoumick, Sagar Roy, Somenath Mitra
Summary: This paper investigates the synergistic effect of air sparging in reducing membrane fouling and enhancing water vapor flux in direct contact membrane distillation. The use of air sparging was found to significantly reduce fouling and improve permeate flux compared to conventional DCMD, especially in desalting high salt concentration brine.
SEPARATION AND PURIFICATION TECHNOLOGY
(2021)
Article
Chemistry, Multidisciplinary
Andrzej Dzienia, Dominik Just, Dawid Janas
Summary: Despite the extensive utilization of carbon nanostructures as sensors, the factors influencing their performance are not fully understood. Most of the established principles only apply to nanocarbon species dispersed in polar environments, so they cannot explain the behavior of single-walled carbon nanotubes (SWCNTs) suspended in organic solvents by conjugated polymers (CPs). Our research provides a thorough understanding of this topic by investigating SWCNT nanocomposites based on polyfluorenes and their co-polymers. The study reveals the complex interactions between polymer structure, SWCNT chirality, and solvent characteristics, leading to a revised mechanism of solvatochromism in SWCNTs.
Article
Optics
Thomas Garm Pedersen
Summary: Coulomb-bound systems in reduced dimensions are sensitive to increased confinement. For instance, the binding energy of hydrogen atoms in two dimensions is four times greater than in three dimensions. Quasi-two-dimensional hydrogen has been experimentally realized as low-dimensional excitons, which are less sensitive to external electric and magnetic perturbations due to confinement. In this study, we examine two-dimensional hydrogen in crossed electric and magnetic fields, providing analytical, numerical, and variational results for binding energy and dipole polarizability in arbitrary magnetic fields.
Article
Chemistry, Multidisciplinary
Wenkai Zheng, Li Xiang, Felipe A. . de Quesada, Mathias Augustin, Zhengguang Lu, Matthew Wilson, Aditya Sood, Fengcheng Wu, Dmitry Shcherbakov, Shahriar Memaran, Ryan E. Baumbach, Gregory T. McCandless, Julia Y. Chan, Song Liu, James H. Edgar, Chun Ning Lau, Chun Hung Lui, Elton J. G. Santos, Aaron Lindenberg, Dmitry Smirnov, Luis Balicas
Summary: Interlayer excitons are studied in hetero-bilayers of metal monochalcogenides, showing adjustable emission spectra and longer lifetimes compared to intralayer excitons. The bound electron-hole pair has a separation close to the calculated interfacial Se separation. These heterostacks have flat interfacial valence bands and are potential candidates for observing magnetism or other correlated electronic phases.
Article
Materials Science, Multidisciplinary
A. O. Slobodeniuk, P. Koutensky, M. Bartos, F. Trojanek, P. Maly, T. Novotny, M. Kozak
Summary: We report on the theoretical and experimental investigation of valley-selective optical Stark and Bloch-Siegert shifts of exciton resonances in monolayers WSe2 and MoS2 induced by strong circularly polarized nonresonant optical fields. We predict and observe transient shifts of both 1sA and 1sB exciton transitions in the linear interaction regime, and explain the polarization dependence of the shifts through a theoretical model.
Article
Chemistry, Multidisciplinary
Fengmei Wang, Ke Qiu, Zihao Zhang, Xinjie Li, Yongjie Cao, Fei Wang
Summary: Non-alkaline zinc-air batteries with reversible O-2/ZnO2 chemistry show excellent stability and reversibility compared to conventional alkaline zinc-air batteries. The use of multi-walled carbon nanotubes (MW-CNTs) in the air cathode design significantly improves the performance of non-alkaline zinc-air batteries, increasing specific capacity, discharge rate performance, and cycling stability. This study provides insights into the cathode design criteria for non-alkaline zinc-air batteries, opening up opportunities for more sustainable zinc-air battery technology.
Article
Chemistry, Physical
Shunsuke Tanaka, Keigo Otsuka, Kensuke Kimura, Akihiro Ishii, Hiroshi Imada, Yousoo Kim, Yuichiro K. Kato
JOURNAL OF PHYSICAL CHEMISTRY C
(2019)
Article
Physics, Multidisciplinary
A. Ishii, H. Machiya, Y. K. Kato
Article
Nanoscience & Nanotechnology
N. Fang, K. Otsuka, A. Ishii, T. Taniguchi, K. Watanabe, K. Nagashio, Y. K. Kato
Article
Optics
D. Yamashita, H. Machiya, K. Otsuka, A. Ishii, Y. K. Kato
Summary: The study demonstrates the integration of an individual single-walled carbon nanotube light emitter onto a microcavity and a waveguide operating in the telecom wavelength regime, showing enhanced light emission and promising potential for carbon-nanotube-based photonics.
Article
Multidisciplinary Sciences
Hiroshi Imada, Miyabi Imai-Imada, Kuniyuki Miwa, Hidemasa Yamane, Takeshi Iwasa, Yusuke Tanaka, Naoyuki Toriumi, Kensuke Kimura, Nobuhiko Yokoshi, Atsuya Muranaka, Masanobu Uchiyama, Tetsuya Taketsugu, Yuichiro K. Kato, Hajime Ishihara, Yousoo Kim
Summary: A single-molecule spectroscopic method with micro-electron volt energy and submolecular-spatial resolution has been developed to induce molecular luminescence in scanning tunneling microscopy. The state-selective characterization of energy levels and linewidths of individual electronic and vibrational quantum states of a single molecule has been demonstrated. Tuning energy levels of molecular systems through the Stark effect and plasmon-exciton coupling in the tunneling junction opens up possibilities for creating designed energy-converting functions.
Article
Multidisciplinary Sciences
Keigo Otsuka, Nan Fang, Daiki Yamashita, Takashi Taniguchi, Kenji Watanabe, Yuichiro K. Kato
Summary: The authors demonstrate a low contamination transfer technique for deterministic placement of structure-specific carbon nanotubes with submicron accuracy, using single-crystalline anthracene as a medium. As device fabrication reaches atomic scales, assembly of atomically defined components becomes crucial.
NATURE COMMUNICATIONS
(2021)
Article
Nanoscience & Nanotechnology
Zhen Li, Keigo Otsuka, Daiki Yamashita, Daichi Kozawa, Yuichiro K. Kato
Summary: Decorating nanoscale pentacene particles onto airsuspended single-walled carbon nanotubes modifies the local energy landscape of excitons. This promotes strong photon antibunching and enhances exciton-exciton annihilation and single-photon emission at room temperature. Noncovalent functionalization using molecules is shown to be an effective approach for energy landscape modification and quantum emission in carbon nanotubes.
Article
Chemistry, Multidisciplinary
Keigo Otsuka, Ryoya Ishimaru, Akari Kobayashi, Taiki Inoue, Rong Xiang, Shohei Chiashi, Yuichiro K. Kato, Shigeo Maruyama
Summary: This article proposes a universal kinetic model to solve the contradictory reports on the growth kinetics of carbon nanotubes. The model is quantitatively verified through experiments. The findings not only resolve discrepancies existing in the literature but also offer rational strategies to control the chirality, length, and density of nanotube arrays for practical applications.
Article
Multidisciplinary Sciences
Daichi Kozawa, Xiaojian Wu, Akihiro Ishii, Jacob Fortner, Keigo Otsuka, Rong Xiang, Taiki Inoue, Shigeo Maruyama, YuHuang Wang, Yuichiro K. Kato
Summary: The functionalization of air-suspended nanotubes through a vapor-phase photochemical reaction is demonstrated, showing the influence of the nanotube structure on the vapor-phase reactivity and emission properties. This provides guidelines for the development of high-performance near-infrared quantum light sources.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Physical
Ruixi Zhang, Ya Feng, Henan Li, Akihito Kumamoto, Shuhui Wang, Yongjia Zheng, Wanyu Dai, Nan Fang, Ming Liu, Takeshi Tanaka, Yuichiro K. Kato, Hiromichi Kataura, Yuichi Ikuhara, Shigeo Maruyama, Rong Xiang
Summary: This study demonstrates the possibility of constructing one-dimensional van der Waals heterostructures on atomically precise, single-chirality SWCNTs. The obtained heterostructures show high crystal quality and different types of BNNTs can be formed on SWCNTs of the identical chirality.
Article
Materials Science, Multidisciplinary
Nan Fang, Daiki Yamashita, Shun Fujii, Keigo Otsuka, Takashi Taniguchi, Kenji Watanabe, Kosuke Nagashio, Yuichiro K. Kato
Summary: This study presents a carefully designed silicon photonic crystal nanobeam cavity for efficient control through 2D materials and demonstrates giant shifts of the resonant wavelength using few-layer flakes. The study also reveals the independence of the dielectric constant of the flakes on the layer number.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Boda Yu, Sadahito Naka, Haruka Aoki, Koichiro Kato, Daiki Yamashita, Shun Fujii, Yuichiro K. Kato, Tsuyohiko Fujigaya, Tomohiro Shiraki
Summary: Defect functionalization of SWCNTs through chemical modification is a promising strategy for generating near-infrared photoluminescence. In this study, aryldiazonium reagents with pi-conjugated ortho-substituents were used to selectively emit single defect photoluminescence in a specific wavelength range.
Article
Physics, Multidisciplinary
Shun Fujii, Koshiro Wada, Ryo Sugano, Hajime Kumazaki, Soma Kogure, Yuichiro K. K. Kato, Takasumi Tanabe
Summary: In this study, we demonstrate a method for broad spectral tuning of Kerr soliton microcombs in a thermally controlled crystalline microresonator with pump-detuning stabilization. Leveraging thermal effects in ultrahigh-Q crystalline magnesium fluoride resonators, the center frequency, repetition frequency, and carrier-envelope offset frequency of the frequency combs can be spectrally tuned. Furthermore, employing quantitative analyses of the fiber-to-resonator coupling efficiency, a 3.4-fold enhancement of soliton comb power is achieved with a temperature change of only 28 K.
COMMUNICATIONS PHYSICS
(2023)
Article
Physics, Multidisciplinary
H. Machiya, D. Yamashita, A. Ishii, Y. K. Kato
Summary: The radiative quantum efficiency of bright excitons in carbon nanotubes can reach near unity through the use of cavity quantum electrodynamical effects.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Physics, Multidisciplinary
C. F. Fong, Y. Ota, Y. Arakawa, S. Iwamoto, Y. K. Kato
Summary: The study demonstrates a scheme for inducing chirality in the cavity modes of an H1 photonic crystal cavity to achieve intrinsic circular polarization. By selectively modifying two air holes around the cavity, the dipole modes interact via asymmetric coherent backscattering, approaching the exceptional point and generating significant circular polarization.
PHYSICAL REVIEW RESEARCH
(2021)
