Article
Multidisciplinary Sciences
Kirill Vasilev, Benjamin Doppagne, Tomas Neuman, Anna Roslawska, Herve Bulou, Alex Boeglin, Fabrice Scheurer, Guillaume Schull
Summary: The authors demonstrate the internal Stark effect by observing spectral shifts in the fluorescence spectrum of a phthalocyanine molecule caused by electrostatic fields generated within the molecule itself. This phenomenon of tuning chromophores' optical properties using electrostatic fields is known as the internal Stark effect (ISE) and plays a crucial role in optimizing complex functions in living organisms. By sequentially removing central protons from a free-base phthalocyanine chromophore with a scanning tunneling microscope, the authors were able to measure the Stark shift in the emission energy caused by the charges confined within the chromophore.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
T. Wang, M. Zhang, L. F. Wei
Summary: Researchers proposed a new method of exciting electrons in the low-temperature system of electrons floating on a liquid helium surface by the mixed effect of THz and GHz electromagnetic waves, which can be experimentally detected using the image-charge approach.
EUROPEAN PHYSICAL JOURNAL PLUS
(2022)
Article
Nanoscience & Nanotechnology
Camila Ianhez-Pereira, Ariano De Giovanni Rodrigues, Marcio Peron Franco de Godoy
Summary: This study investigated the infrared optical emission of Er3+ doped ZnO hosts, using spray pyrolysis during thin film growth. Different molarity conditions affected the growth of the films and their optical properties. The infrared emissions were influenced by the Stark effect, which was dependent on synthesis parameters.
SCRIPTA MATERIALIA
(2021)
Article
Chemistry, Multidisciplinary
Zhihua Zhao, Yinping Wang, Celine Delmas, Christophe Mingotaud, Jean-Daniel Marty, Myrtil L. Kahn
Summary: The control and understanding of the nucleation and growth of nano-objects are crucial for improving and exploring new applications of materials at the nanoscale. Analyzing the formation of anisotropic ZnO nanoparticles under different experimental conditions revealed a growth process by oriented attachment, allowing for easy tuning of the size and aspect ratio of the nanostructures. By using statistical tools, the relative importance of experimental parameters governing the growth of nano-objects was highlighted, providing valuable insights for further research in this field.
NANOSCALE ADVANCES
(2021)
Article
Chemistry, Physical
Jialu Li, Dengfeng Wang, Guofeng Zhang, Changgang Yang, Wenli Guo, Xue Han, Xiuqing Bai, Ruiyun Chen, Chengbing Qin, Jianyong Hu, Liantuan Xiao, Suotang Jia
Summary: In this study, the blinking mechanism and quantum-confined Stark effect (QCSE) of single CdSe/CdS/ZnS quantum dots were investigated using single-dot PL spectroscopy. Negative surface charges were found to simultaneously suppress PL blinking and spectral diffusion, while positive surface charges changed the blinking mechanisms. Two types of QCSE were observed, and a significant QCSE-induced spectral broadening was measured.
Article
Chemistry, Multidisciplinary
Zhen-Ya Liu, An-An Liu, Haohao Fu, Qing-Yuan Cheng, Ming-Yu Zhang, Man-Man Pan, Li-Ping Liu, Meng-Yao Luo, Bo Tang, Wei Zhao, Juan Kong, Xueguang Shao, Dai-Wen Pang
Summary: Ag2Te quantum dots emitting from 950 to 2100 nm have been synthesized via trialkylphosphine-controlled growth, achieving precise size control. By controlling dissolution effect, the monomer supply kinetics can be regulated, leading to precise size control of Ag2Te QDs with emission tunability, providing new possibilities for multicolor and deep-tissue in vivo fluorescence imaging.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Physical
Yakov Braver, Leonas Valkunas, Andrius Gelzinis
Summary: In this work, a theoretical framework for calculations of Stark absorption and Stark fluorescence spectra based on quantum-classical theory is proposed. The methods show accurate results for a wide range of systems, including those containing charge-transfer states. The presence of states with large static dipole moments can cause significant changes in the total fluorescence yield of a system in the presence of an external electric field, an effect correctly captured by the quantum-classical methods.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Optics
Pieter Geiregat, Carmelita Roda, Ivo Tanghe, Shalini Singh, Alessio Di Giacomo, Delphine Lebrun, Gianluca Grimaldi, Jorick Maes, Dries Van Thourhout, Iwan Moreels, Arjan J. Houtepen, Zeger Hens
Summary: In this study, the researchers analyzed the oscillator strength of exciton transitions in 2D CdSe nanoplatelets using the optically induced Stark effect. They found that the actual oscillator strengths were 50 times smaller than expected based on linear absorption coefficients, suggesting that the exciton absorption line is a sum of low oscillator strength transitions. The authors propose that this discrepancy is due to strong exciton center-of-mass localization and suggest that thermal effects may contribute to exciton localization.
LIGHT-SCIENCE & APPLICATIONS
(2021)
Article
Physics, Multidisciplinary
Ankang Zhu, Zheng Chen, Yuyan Han, Mengcheng Zhu, Huanhuan Wang, Minglong Han, Liang Li, Xue Liu, Guolin Zheng, Xiangde Zhu, Wenshuai Gao, Mingliang Tian
Summary: In this study, the possible transport signals of topological surface states in a 21nm thick beta-PdBi2 nanoflake were investigated. The resistance showed a semiconductor-metal transition followed by an upturned behavior as the temperature decreased. The observed large and unsaturated longitudinal magnetoresistance and Shubnikov-de Hass oscillation in Hall resistance suggested the presence of carriers with characteristics of relativistic particles. Angle-dependent quantum oscillations indicated a two-dimensional Fermi surface topology. A giant anisotropic magnetoresistance as high as 98% was detected when rotating the magnetic field. These findings provide valuable insights into the topological properties of the low-dimensional topological superconductor candidate alpha-PdBi2.
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY
(2023)
Article
Materials Science, Multidisciplinary
Nathan D. Cottam, Chengxi Zhang, Joni L. Wildman, Amalia Patane, Lyudmila Turyanska, Oleg Makarovsky
Summary: This study reveals a slow and reversible quenching of NC photoluminescence, caused by a light-induced Stark effect involving defects on the NC surface and the redistribution of photoexcited carriers onto the NC surface. This phenomenon can impact the operation of optoelectronic devices based on these NCs.
ADVANCED OPTICAL MATERIALS
(2021)
Article
Optics
B. C. Hu, N. Zhou, Q. Y. Zhang, C. Y. Ma
Summary: The photoluminescence spectra of ZnO samples showed that the excitation behavior of the structured green luminescence band is influenced by surface conditions and defects density near the sample surface. The efficacy of SiOx passivation on the green luminescence band is determined by the presence of imperfections on the sample surface. The phonon energy in the green luminescence band is associated with surface optical mode.
JOURNAL OF LUMINESCENCE
(2021)
Article
Chemistry, Physical
Shihui Wen, Du Li, Yongtao Liu, Chaohao Chen, Fan Wang, Jiajia Zhou, Guochen Bao, Le Zhang, Dayong Jin
Summary: This study provides a quantitative guide for designing high-brightness UCNPs under different excitation conditions, including the optimum concentrations of sensitizer and emitter ions, and the impact of different concentrations on brightness and NIR/blue ratio.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Nanoscience & Nanotechnology
L. K. Rodenbach, I. T. Rosen, E. J. Fox, Peng Zhang, Lei Pan, Kang L. Wang, M. A. Kastner, D. Goldhaber-Gordon
Summary: By comparing transport measurements of devices fabricated from Cr-doped (BiSb)(2)Te-3, it was found that bulk conduction is the dominant source of dissipation at all temperatures and electric field values, and the breakdown of the QAH phase is a bulk process. This methodology can be used to identify dissipative conduction mechanisms in new QAH materials for achieving the QAH effect at higher temperatures.
Article
Chemistry, Multidisciplinary
Jian Zhou, Fengyang Ma, Kai Chen, Wuyan Zhao, Riyi Yang, Chong Qiao, Hong Shen, Wan-Sheng Su, Ming Lu, Yuxiang Zheng, Rongjun Zhang, Liangyao Chen, Songyou Wang
Summary: Based on first principles calculations, this study investigates the optical properties of silicon quantum dots (Si-QDs) considering quantum size effect and surface effect. The results demonstrate significant differences in emission wavelength and intensity of Si-QD interface states connected by different ligands, with silicon-oxygen double bonds exhibiting the strongest emission. The study deepens the understanding of the photoluminescence mechanism of Si-QDs and provides a direction for enhancing the photoluminescence quantum efficiency of silicon nanocrystals and fabricating silicon-based photonic devices.
NANOSCALE ADVANCES
(2023)
Article
Chemistry, Multidisciplinary
Jeongeon Kim, Xenia Medvedeva, Jury J. Medvedev, Cheongwon Bae, Juyeong Kim, Anna Klinkova
Summary: Understanding the relationship between structure and performance in nanoscale electrocatalysts for urea electrolysis is important for efficient waste treatment and hydrogen production or CO2 reduction. We investigate the role of lattice strain in Pd-Ni core-shell nanocubes on the dominance of the urea overoxidation pathway.
Article
Chemistry, Multidisciplinary
Xin Zhang, Linqing Qin, Yuhao Li, Jianwei Yu, Hao Chen, Xiaobin Gu, Yanan Wei, Xinhui Lu, Feng Gao, Hui Huang
Summary: By using noncovalent conformational locks (NoCLs), a pair of regioisomeric small-molecule donors (SMDs) has been synthesized, and the significant influence of regioisomeric effect on device performance has been demonstrated. Among different SMDs, BT-O2 exhibits better performance, and the introduction of fullerene derivative PC71BM further improves the performance.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Yaokai Li, Yuan Guo, Zeng Chen, Lingling Zhan, Chengliang He, Zhaozhao Bi, Nannan Yao, Shuixing Li, Guanqing Zhou, Yuanping Yi, Yang (Michael) Yang, Haiming Zhu, Wei Ma, Feng Gao, Fengling Zhang, Lijian Zuo, Hongzheng Chen
Summary: This study systematically investigates the working mechanism of ternary blend organic photovoltaics based on non-fullerene acceptors (NFAs). Molecular dynamics simulations and morphology characterization reveal that the addition of larger band gap and highly miscible NFAs improves composition-dependent band gap and charge recombination, leading to enhanced power conversion efficiency.
ENERGY & ENVIRONMENTAL SCIENCE
(2022)
Review
Materials Science, Multidisciplinary
Xiaobo Shang, Li Wan, Lin Wang, Feng Gao, Hanying Li
Summary: Detecting circularly polarized light (CPL) signals is crucial in advanced sensing technologies, with CPL detectors of different wavelengths having distinct applications. This review introduces the working principle and material design strategies of state-of-the-art CPL photodetectors, as well as recent developments in chiral materials for CPL detection and strategies for improving detection capabilities.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
Article
Chemistry, Physical
Bin Zhang, Johan Klarbring, Fuxiang Ji, Sergei Simak, Igor A. Abrikosov, Feng Gao, Galyna Yu Rudko, Weimin M. Chen, Irina A. Buyanova
Summary: Phonon-phonon and electron/exciton-phonon coupling are found to play a vital role in the thermal, electronic, and optical properties of metal halide perovskites. Our study focuses on the evaluation of phonon anharmonicity and coupling between electronic and vibrational excitations in the novel material, Cs2NaFeCl6, through Raman measurements and theoretical calculations. The results highlight the significance of phonon-phonon and electron-phonon interactions in the electronic properties of Cs2NaFeCl6.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Jiajun Qin, Yang Tang, Jia Zhang, Tangyao Shen, Max Karlsson, Tiankai Zhang, Weidong Cai, Lei Shi, Wei-Xin Ni, Feng Gao
Summary: In this study, we evaluate the threshold carrier density of optically pumped lasers and find that the carrier cooling process in perovskites is slower than previously assumed. However, we observe that lower energy photon excitation speeds up the carrier cooling process and facilitates efficient carrier accumulation. By extrapolating the optical pumping threshold to band edge excitation, we obtain a critical threshold carrier density one order of magnitude lower than conventional estimates.
MATERIALS HORIZONS
(2023)
Article
Chemistry, Multidisciplinary
Xabier Rodriguez-Martinez, Paula Hartnagel, Sergi Riera-Galindo, Gulzada Beket, Thomas Osterberg, Feng Gao, Thomas Kirchartz, Olle Inganas
Summary: Non-fullerene acceptors have revolutionized indoor organic photovoltaics with high power conversion efficiencies, but transferring this performance to larger-scale prototyping remains challenging. The PM6:IO4Cl blend, a successful indoor OPV photoactive layer, is investigated for its industrial potential, and the thick and semitransparent devices are fabricated in air. Anomalous current-voltage characteristics are observed, with the cathode side generally outperforming the anode side due to a dead layer at the PAL/anode contact interface. Symmetric J-V curves and improved light utilization efficiency are achieved by making the PALs thin enough. Certain all-polymer and polymer:fullerene blends are identified as suitable candidates for thick device up-scaling, and ternary blends show potential in mitigating electrical asymmetry.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Optics
Li Wan, Rui Zhang, Eunkyung Cho, Hongxiang Li, Veaceslav Coropceanu, Jean-Luc Bredas, Feng Gao
Summary: We propose a widely applicable strategy to fill the spectral gap of circularly polarized light (CPL) detection in the near-infrared (NIR) region by directly inducing chiroptical activity in planar non-fullerene acceptors. This strategy is found to be effective in a wide series of state-of-the-art non-fullerene acceptor families, including ITIC5, o-IDTBR6, and Y6 analogues.
Editorial Material
Chemistry, Multidisciplinary
Feng Gao, Elsa Reichmanis
Review
Nanoscience & Nanotechnology
Baodan Zhao, Maria Vasilopoulou, Azhar Fakharuddin, Feng Gao, Abd. Rashid Bin Mohd Yusoff, Richard H. Friend, Dawei Di
Summary: Perovskite light-emitting diodes (LEDs) have shown great potential for display and lighting applications with external quantum efficiencies exceeding 20% for various colors. However, the majority of internally generated photons are trapped in the devices and lose energy through lossy channels, suggesting the need for effective light management strategies. By analyzing the intrinsic optical properties of perovskite materials and the extrinsic properties related to device structures, this Review highlights the possibility of substantially exceeding the conventional limits of planar organic LED devices and suggests new approaches for achieving ultrahigh efficiencies in perovskite LEDs.
NATURE NANOTECHNOLOGY
(2023)
Article
Nanoscience & Nanotechnology
Bin Zhang, Yuqing Huang, Fuxiang Ji, Xiaohe Miao, Feng Gao, Weimin M. Chen, Irina A. Buyanova
Summary: We report the first observation of second harmonic generation (SHG) from halide double perovskite single crystals. The SHG efficiency of these materials with centrosymmetric crystalline structures is strongly dependent on the measurement temperature, increasing by up to 3 orders of magnitude at low temperatures under light illumination. The enhancement is attributed to the build-up of a light-induced electric field within the near-surface region.
Article
Physics, Multidisciplinary
Joakim Argillander, Alvaro Alarcon, Chunxiong Bao, Chaoyang Kuang, Gustavo Lima, Feng Gao, Guilherme B. Xavier
Summary: The authors demonstrate a certified quantum random number generator using a metal-halide perovskite light emitting diode. This new technology has the potential to revolutionize optical communication and lighting devices, and also has applications in quantum technologies.
COMMUNICATIONS PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Gulzada Beket, Anton Zubayer, Qilun Zhang, Jochen Stahn, Fredrik Eriksson, Mats Fahlman, Thomas Osterberg, Jonas Bergqvist, Feng Gao
Summary: Harvesting indoor light for electronic devices has become an application scenario for emerging photovoltaics, especially organic photovoltaics (OPVs). This study investigates the impact of fullerene-based acceptor interlayer on the performance of laminated OPVs for indoor applications. Incorporating insulating organic components into fullerene interlayers improves energy level alignment and reduces voltage loss across the interface.
Article
Chemistry, Multidisciplinary
Mengyun Chen, Tiankai Zhang, Anna Elsukova, Zhangjun Hu, Rui Zhang, Yonghong Wang, Xianjie Liu, Xiaoke Liu, Feng Gao
Summary: Stable CsPbI3 nanoplatelets with lower surface-area-to-volume ratio and improved spectral stability are synthesized by accelerating the crystallization process using kinetic control.
Article
Chemistry, Multidisciplinary
Ruijie Ma, Jianwei Yu, Tao Liu, Guangye Zhang, Yiqun Xiao, Zhenghui Luo, Gaoda Chai, Yuzhong Chen, Qunping Fan, Wenyan Su, Gang Li, Ergang Wang, Xinhui Lu, Feng Gao, Bo Tang, He Yan
Summary: In this study, the morphology of the active layer in all-polymer solar cells was fine-tuned using solvent additive and polymer additive, resulting in an efficiency of 16.04%. Altering the shape of crystallites enhanced charge transport, reduced recombination, and suppressed energy loss, leading to improved device efficiency and stability.
Review
Chemistry, Physical
Man Li, Faming Li, Jue Gong, Tiankai Zhang, Feng Gao, Wen-Hua Zhang, Mingzhen Liu
Summary: Metal halide perovskites, particularly lead-based ones, have been extensively studied in the optoelectronic materials field due to their unique properties, but concerns about the toxicity of lead have prompted the search for non-toxic alternatives, with tin(II) emerging as a promising candidate. While tin-based perovskite solar cells have shown progress, issues like rapid oxidation and decomposition still impact their stability and efficiency.
