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  • 任祥華 博士
    Quantum Sci. Tech. 9, 025020 (2024).
    Scalable graph states are essential for measurement-based quantum computation and many entanglement-assisted applications in quantum technologies. Generation of these multipartite entangled states requires a controllable and efficient quantum device with delicate design of generation protocol. Here we propose to prepare high-fidelity and scalable graph states in one and two dimensions, which can be tailored in an atom-nanophotonic cavity via state carving technique. We propose a systematic protocol to carve out unwanted state components, which facilitates scalable graph states generations via adiabatic transport of a definite number of atoms in optical tweezers. An analysis of state fidelity is also presented, and the state preparation probability can be optimized via multiqubit state carvings and sequential single-photon probes. Our results showca ...
  • 賴品光 博士
    Nature Protocols. doi: 10.1038/s41596-021-00564-8 (2021).
    The dynamics of DNA double-strand break (DSB) repairs including homology-directed repair and nonhomologous end joining play an important role in diseases and therapies. However, investigating DSB repair is typically a low-throughput and cross-sectional process, requiring disruption of cells and organisms for subsequent nuclease-, sequencing- or reporter-based assays. In this protocol, we provide instructions for establishing a bioluminescent repair reporter system using engineered Gaussia and Vargula luciferases for noninvasive tracking of homology-directed repair and nonhomologous end joining, respectively, induced by SceI meganuclease, SpCas9 or SpCas9 D10A nickase-mediated editing. We also describe complementation with orthogonal DSB repair assays and omics analyses to validate the reporter readouts. The bioluminescent repair reporter system pro ...
  • 羅佩凌 博士
    J. Phys. Chem. Lett.,15, 3733–3739 (2024)
    The radical–radical reaction between OH and HO2 has been considered for a long time as an important reaction in tropospheric photochemistry and combustion chemistry. However, a significant discrepancy of an order of magnitude for rate coefficients of this reaction is found between two recent experiments. Herein, we investigate the reaction OH + HO2 via direct spectral quantification of both the precursor (H2O2) and free radicals (OH and HO2) upon the 248 nm photolysis of H2O2 using infrared two-color time-resolved dual-comb spectroscopy. With quantitative and kinetic analysis of concentration profiles of both OH and HO2 at varied conditions, the rate coefficient kOH+HO2 is determined to be (1.10 ± 0.12) &time ...
  • 任祥華 博士
    Nature Communications 13, 4598 (2022).
    Explorations of symmetry and topology have led to important breakthroughs in quantum optics, but much richer behaviors arise from the non-Hermitian nature of light-matter interactions. A high-reflectivity, non-Hermitian optical mirror can be realized by a two-dimensional subwavelength array of neutral atoms near the cooperative resonance associated with the collective dipole modes. Here we show that exceptional points develop from a nondefective degeneracy by lowering the crystal symmetry of a square atomic lattice, and dispersive bulk Fermi arcs that originate from exceptional points are truncated by the light cone. From its nontrivial energy spectra topology, we demonstrate that the geometry-dependent non-Hermitian skin effect emerges in a ribbon geometry. Furthermore, skin modes localized at a boundary show a scale-free behavior that stems from  ...
  • 詹楊皓 博士
    Proceedings of National Academy of Sciences, 118 (25) e1906938118 (2021).
    Shift current is a direct current generated from nonlinear light–matter interaction in a noncentrosymmetric crystal and is considered a promising candidate for next-generation photovoltaic devices. The mechanism for shift currents in real materials is, however, still not well understood, especially if electron–hole interactions are included. Here, we employ a first-principles interacting Green’s-function approach on the Keldysh contour with real-time propagation to study photocurrents generated by nonlinear optical processes under continuous wave illumination in real materials. We demonstrate a strong direct current shift current at subbandgap excitation frequencies in monolayer GeS due to strongly bound excitons, as well as a giant excitonic enhancement in the shift current coefficients at above bandgap photon frequencies. Our re ...
  • 許良彥 博士
    J. Phys. Chem. Lett. 14, 25, 5924–5931 (2023).
    To explore non-adiabatic effects caused by electromagnetic (EM) vacuum fluctuations in molecules, we develop a general theory of internal conversion (IC) in the framework of quantum electrodynamics and propose a new mechanism, “quantum electrodynamic internal conversion” (QED-IC). The theory allows us to compute the rates of the conventional IC and QED-IC processes at the first-principles level. Our simulations manifest that, under experimentally feasible weak light–matter coupling conditions, EM vacuum fluctuations can significantly affect IC rates by an order of magnitude. Moreover, our theory elucidates three key factors in the QED-IC mechanism: the effective mode volume, coupling-weighted normal mode alignment, and molecular rigidity. The theory successfully captures the nucleus–photon interaction in the factor “co ...
  • 許良彥 博士
    Journal of Physical Chemistry Letters, 13, 9695–9702 (2022).
    Richard Feynman stated that “The theory behind chemistry is quantum electrodynamics”. However, harnessing quantum-electrodynamic (QED) effects to modify chemical reactions is a grand challenge and currently has only been reported in experiments using cavities due to the limitation of strong light–matter coupling. In this article, we demonstrate that QED effects can significantly enhance the rate of electron transfer (ET) by several orders of magnitude in the absence of cavities, which is implicitly supported by experimental reports. To understand how cavity-free QED effects are involved in ET reactions, we incorporate the effect of infinite one-photon states into Marcus theory, derive an explicit expression for the rate of radiative ET, and develop the concept of “electron transfer overlap”. Moreover, QED effects may l ...
  • 謝佳龍 博士
    ACS Nano, 16(2): 2774-2788 (2022).
    Chromatin is a DNA–protein complex that is densely packed in the cell nucleus. The nanoscale chromatin compaction plays critical roles in the modulation of cell nuclear processes. However, little is known about the spatiotemporal dynamics of chromatin compaction states because it remains difficult to quantitatively measure the chromatin compaction level in live cells. Here, we demonstrate a strategy, referenced as DYNAMICS imaging, for mapping chromatin organization in live cell nuclei by analyzing the dynamic scattering signal of molecular fluctuations. Highly sensitive optical interference microscopy, coherent brightfield (COBRI) microscopy, is implemented to detect the linear scattering of unlabeled chromatin at a high speed. A theoretical model is established to determine the local chromatin density from the statistical fluctuation of the ...
  • 余慈顏 博士
    Nature Communications, 13, 1513 (2022).
    Limited methods are available for investigating the reorientational dynamics of A-site cations in two-dimensional organic–inorganic hybrid perovskites (2D OIHPs), which play a pivotal role in determining their physical properties. Here, we describe an approach to study the dynamics of A-site cations using solid-state NMR and stable isotope labelling. 2H NMR of 2D OIHPs incorporating methyl-d3-ammonium cations (d3-MA) reveals the existence of multiple modes of reorientational motions of MA. Rotational-echo double resonance (REDOR) NMR of 2D OIHPs incorporating 15N- and 13C-labeled methylammonium cations (13C,15N-MA) reflects the averaged dipolar coupling between the C and N nuclei undergoing different modes of motions. Our study reveals the interplay between the A-si ...
  • 賴品光 博士
    Advanced Materials. https://doi.org/10.1002/adma.202208966 (2023).
    Our latest publication employed PalmGRET, a bioluminescence-resonance-energy-transfer (BRET)-based EV reporter, to discover an abundant release of big EVs (bEVs; >200 nm) by aggressive breast cancers when compared to epithelial and less malignant cells. bEVs have been largely overshadowed by small EVs (sEVs; <200 nm) in EV research in the past decades. This is the first study to accurately detect and systematically compare biophysical property and in vivo profiles of breast cancer bEVs and sEVs. This is followed by the identification of EV surface oncoproteins, and their role in modulating organotropism and tumorigenic potential of the bEVs and sEVs. Our landmark findings impart a broad and deep reference for upcoming EV studies, with an emphasis on EV engineering for diagnosis and therapeutic applications.
  • 林靖衛 博士
    ACS Nano 18, 18534–18547 (2024).
    Cytometry plays a crucial role in characterizing cell properties, but its restricted optical window (400-850 nm) limits the number of stained fluorophores that can be detected simultaneously and hampers the study and utilization of short-wave infrared (SWIR; 900-1,700 nm) fluorophores in cells. Here we introduce two SWIR-based methods to address these limitations: SWIR flow cytometry and SWIR image cytometry. We develop a quantification protocol for deducing cellular fluorophore mass. Both systems achieve a limit of detection of ~0.1 fg cell−1 within a 30-min experimental timeframe, using individualized, high-purity (6,5) single-wall carbon nanotubes as a model fluorophore and macrophage-like RAW264.7 as a model cell line. This high-sensitivity feature reveals that low-dose (6,5) serves as an antioxidant, and cell morphology a ...
  • 謝雅萍 博士
    Nature Communications, 12:6291 (2021).
    We here report on the direct observation of ferroelectric properties of water ice in its 2D phase. Upon nanoelectromechanical confinement between two graphene layers, water forms a 2D ice phase at room temperature that exhibits a strong and permanent dipole which depends on the previously applied field, representing clear evidence for ferroelectric ordering. Characterization of this permanent polarization with respect to varying water partial pressure and temperature reveals the importance of forming a monolayer of 2D ice for ferroelectric ordering which agrees with ab-initio and molecular dynamics simulations conducted. The observed robust ferroelectric properties of 2D ice enable novel nanoelectromechanical devices that exhibit memristive properties. A unique bipolar mechanical switching behavior is observed where previous charging history contro ...
  • 王偉華 博士
    Nano Lett., 22, 6, 2270–2276 (2022).
    Understanding the Coulomb interactions between two-dimensional (2D) materials and adjacent ions/impurities is essential to realizing 2D material-based hybrid devices. Electrostatic gating via ionic liquids (ILs) has been employed to study the properties of 2D materials. However, the intrinsic interactions between 2D materials and ILs are rarely addressed. This work studies the intersystem Coulomb interactions in IL-functionalized InSe field-effect transistors by displacement current measurements. We uncover a strong self-gating effect that yields a 50-fold enhancement in interfacial capacitance, reaching 550 nF/cm2 in the maximum. Moreover, we reveal the IL-phase-dependent transport characteristics, including the channel current, carrier mobility, and density, substantiating the self-gating at the InSe/IL interface. The dominance of self ...
  • 謝雅萍 博士
    Nano Lett., https://doi.org/10.1021/acs.nanolett.1c02331 (2021).
    We here demonstrate the multifunctional properties of atomically thin heterojunctions that are enabled by strong interfacial interactions and their integration into ultra-high performance, self-powered sensors. Epitaxial alignment between tin diselenide and graphene through direct growth produces thermoelectric and mechanoelectric properties beyond the ability of either component. An unprecedented ZT of 2.43 originated from the synergistic combination of graphene’s high carrier conductivity and SnSe2 mediated thermal conductivity lowering. Moreover, strong interaction at the SnSe2/graphene interface produces stress localization that results in a novel 2D-crack-assisted strain sensing mechanism whose sensitivity (GF=450) is superior to all other 2D materials. Finally, the graphene-assisted growth process, permits the formation of hi ...
  • 陳貴賢 博士
    Nano Energy, 93, 106809 (2022).
    Employing direct Z-scheme semiconductor heterostructures in photocatalysis offers efficient charge carrier separation and isolation of both redox reactions, thus beneficial to reduce CO2 into solar fuels. Here, a ZnS/ZnIn2S4 heterostructure, comprising cubic ZnS nanocrystals on hexagonal ZnIn2S4 (ZIS) nanosheets, is successfully fabricated in a single-pot hydrothermal approach. The composite ZnS/ZnIn2S4 exhibits microstrain at its interface with an electric field favorable for Z-scheme. At an optimum ratio of Zn:In (~ 1:0.5), an excellent photochemical quantum efficiency of around 0.8% is reached, nearly 200-fold boost compared with pristine ZnS. Electronic levels and band alignments are deduced from ultraviolet photoemission spectroscopy and UV-Vis. Evidence of the direct ...
  • 羅佩凌 博士
    Communications Chemistry, 6, 130 (2023)
    Ozonolysis of isoprene is considered to be an important source of formic acid (HCOOH), but its underlying reaction mechanisms related to HCOOH formation are poorly understood. Here, we report the kinetic and product studies of the reaction between the simplest Criegee intermediate (CH2OO) and formaldehyde (HCHO), both of which are the primary products formed in ozonolysis of isoprene. By utilizing time-resolved infrared laser spectrometry with the multifunctional dual-comb spectrometers, the rate coefficient kCH2OO+HCHO is determined to be (4.11 ± 0.25) × 10−12 cm3 molecule−1 s−1 at 296 K and a negative temperature dependence of the rate coefficient is observed and described by an Arrheni ...
  • 張煥正 博士
    Nano Lett. 23, 9811–9816 (2023).
    Extreme ultraviolet (EUV) radiation with wavelengths of 10 – 121 nm has drawn considerable attention recently for its use in photolithography to fabricate nanoelectronic chips.  This study demonstrates, for the first time, fluorescent nanodiamonds (FNDs) with nitrogen-vacancy (NV) centers as scintillators to image and characterize EUV radiations.  The FNDs employed are ~100 nm in size; they form a uniform and stable thin film on an indium tin oxide-coated slide by electrospray deposition.  The film is non-hygroscopic, photostable, and can emit bright red fluorescence from NV0 centers when excited by EUV light.  An FND-based imaging device has been developed and applied for beam diagnostics of 50 nm and 13.5 nm synchrotron radiations, achieving a spatial resolution of 30 μm using a film of ~1 μm thickness.& ...



Experimental Probing of Broad Regions of a Chemical Reaction Coordinate: the Story of Haloethanes and Charge Transfer
Prof. Richard Loomis, Washington University in Saint Louis, USA
2024-08-08 下午 02:30  浦大邦紀念講堂