Correlated Magnetic and Electrical Phenomena in Epitaxially Weaved Manganite Lateral Homostructures.

Artificially aligned or positioned functional materials are essential building blocks for modern devices and nanoelectronics. Since the emergence of 2D materials, the vertical stacking/integration of exotic materials has garnered increasing attention. However, controlling homostructures, e.

Redox-Gated Optical Modulation of Coumarin-Triphenyliminophosphorane Fluorophores.

Novel coumarin-triphenyliminophosphorane (TPIPP) fluorophores, synthesized via a nonhydrolytic Staudinger reaction, exhibit remarkable redox-responsive optical properties. Upon chemical and electrochemical oxidation, these compounds display a hypsochromic shift in absorption from 430 to 350 nm, accompanied by up to 11-fold fluorescence enhancement under 405 nm excitation. The fluorescence switching occurs at an electrochemical oxidation potential of approximately +2.

Background-free mid-infrared absorption spectroscopy using sub-cycle pulses.

We have demonstrated highly sensitive single-shot based background-free mid-infrared (MIR) absorption spectroscopy using sub-cycle MIR pulses generated through filamentation. The MIR pulse transmitted through a sample was upconverted with a fast rising and long tailing gate pulse through four-wave difference frequency generation in a silicon membrane. By recording the upconverted spectrum of the free induction decay alone, we successfully measured the absorption spectrum as a positive signal in the wavenumber range from 500 to 4500 cm, which covers both the fingerprint and functional group regions.

Modulation and real-time monitoring of the carrier-envelope phase of terahertz pulses based on shaping of near-infrared femtosecond pulses.

We propose a novel, to our knowledge, method for modulating and real-time monitoring of the carrier-envelope phase (CEP) of terahertz (THz) pulses. CEP is an essential parameter in the interaction of THz waves with matter due to the difference in temporal symmetry when the carrier is extended for several cycles. CEP can be continuously modulated at full range with high speed by oscillating the optical path length of the Michelson interferometer under 1 µm, as confirmed by electro-optic (EO) sampling.

Three-dimensional ultrafast charge-density-wave dynamics in CuTe.

Charge density waves (CDWs) involved with electronic and phononic subsystems simultaneously are a common quantum state in solid-state physics, especially in low-dimensional materials. However, CDW phase dynamics in various dimensions are yet to be studied, and their phase transition mechanism is currently moot. Here we show that using the distinct temperature evolution of orientation-dependent ultrafast electron and phonon dynamics, different dimensional CDW phases are verified in CuTe.

Dual-plasmonic Au@CuS yolk@shell nanocrystals for photocatalytic hydrogen production across visible to near infrared spectral region.

Near infrared energy remains untapped toward the maneuvering of entire solar spectrum harvesting for fulfilling the nuts and bolts of solar hydrogen production. We report the use of Au@CuS yolk@shell nanocrystals as dual-plasmonic photocatalysts to achieve remarkable hydrogen production under visible and near infrared illumination. Ultrafast spectroscopic data reveal the prevalence of long-lived charge separation states for Au@CuS under both visible and near infrared excitation.

Directly Unveiling the Energy Transfer Dynamics between Alq Molecules and Si by Ultrafast Optical Pump-Probe Spectroscopy.

The energy transfer (ET) between organic molecules and semiconductors is a crucial mechanism for enhancing the performance of semiconductor-based optoelectronic devices, but it remains undiscovered. Here, ultrafast optical pump-probe spectroscopy was utilized to directly reveal the ET between organic Alq molecules and Si semiconductors. Ultrathin SiO dielectric layers with a thickness of 3.

Investigation of TiO nanoparticle interactions in the fibroblast NIH-3T3 cells via liquid-mode atomic force microscope.

Long before we recognized how significant they were, nanoparticles were already all around in the environment. Since then, an extensive number of synthetic nanoparticles have been engineered to improve our quality of life through rigorous scientific research on their uses in practically every industry, including semiconductor devices, food, medicine, and agriculture. The extensive usage of nanoparticles in commodities that come into proximity with human skin and internal organs through medicine has raised significant concerns over the years.

High-speed scanless entire bandwidth mid-infrared chemical imaging.

Mid-infrared spectroscopy probes molecular vibrations to identify chemical species and functional groups. Therefore, mid-infrared hyperspectral imaging is one of the most powerful and promising candidates for chemical imaging using optical methods. Yet high-speed and entire bandwidth mid-infrared hyperspectral imaging has not been realized.

Enhance high harmonic generation (HHG) efficiency via compact multi-plate continuum post-compression for time-resolved angle-resolved photoemission spectroscopy.

Time-resolved angle-resolved photoemission spectroscopy (Tr-APRES) gives direct insight into electron dynamics by providing temporal-, energy-, and momentum-resolved information in one experiment. A major obstacle to using high harmonic generation (HHG) probe pulses for photoemission spectroscopy is the low conversion efficiency, that is, the low flux of probe photons. We use a Yb-KGW based duo-laser source with an oscillator to pump two separate amplifiers and generate two synchronized pulsed laser sources with average energies of 7.

Few-cycle THz wave manipulation with a high degree of freedom via f-t modulation.

THz waves have been intensively applied in many fields, e.g., spectroscopy, imaging, and communications.

Spin-Polarized Photocatalytic CO Reduction of Mn-Doped Perovskite Nanoplates.

"Spin" has been recently reported as an important degree of electronic freedom to improve the performance of electrocatalysts and photocatalysts. This work demonstrates the manipulations of spin-polarized electrons in CsPbBr halide perovskite nanoplates (NPLs) to boost the photocatalytic CO reduction reaction (CORR) efficiencies by doping manganese cations (Mn) and applying an external magnetic field. Mn-doped CsPbBr (Mn-CsPbBr) NPLs exhibit an outstanding photocatalytic CORR compared to pristine CsPbBr NPLs due to creating spin-polarized electrons after Mn doping.

Energy-Resolved Ultrafast Spectroscopic Investigation on the Spin-Coupled Electronic States in Multiferroic Hexagonal HoMnO.

A complete temperature-dependent scheme of the Mn on-site d-d transitions in multiferroic hexagonal HoMnO (-HoMnO) thin films was unveiled by energy-resolved ultrafast spectroscopy. The results unambiguously revealed that the ultrafast responses of the and states differed significantly in the hexagonal HoMnO. We demonstrated that the short-range antiferromagnetic and ferroelectric orderings are more relevant to the state, whereas the long-range antiferromagnetic ordering is intimately coupled to both the and states.

Twisted oxide lateral homostructures with conjunction tunability.

Epitaxial growth is of significant importance over the past decades, given it has been the key process of modern technology for delivering high-quality thin films. For conventional heteroepitaxy, the selection of proper single crystal substrates not only facilitates the integration of different materials but also fulfills interface and strain engineering upon a wide spectrum of functionalities. Nevertheless, the lattice structure, regularity and crystalline orientation are determined once a specific substrate is chosen.

Stabilized High-Membered and Phase-Pure 2D All Inorganic Ruddlesden-Popper Halide Perovskites Nanocrystals as Photocatalysts for the CO Reduction Reaction.

In contrast to the 2D organic-inorganic hybrid Ruddlesden-Popper halide perovskites (RPP), a new class of 2D all inorganic RPP (IRPP) has been recently proposed by substituting the organic spacers with an optimal inorganic alternative of cesium cations (Cs ). Nevertheless, the synthesis of high-membered 2D IRPPs (n > 1) has been a very challenging task because the Cs need to act as both spacers and A-site cations simultaneously. This work presents the successful synthesis of stable phase-pure high-membered 2D IRPPs of Cs Pb Br nanosheets (NSs) with n = 3 and 4 by employing the strategy of using additional strong binding bidentate ligands.

Using Exciton/Trion Dynamics to Spatially Monitor the Catalytic Activities of MoS during the Hydrogen Evolution Reaction.

The adsorption and desorption of electrolyte ions strongly modulates the carrier density or carrier type on the surface of monolayer-MoS catalyst during the hydrogen evolution reaction (HER). The buildup of electrolyte ions onto the surface of monolayer MoS during the HER may also result in the formation of excitons and trions, similar to those observed in gate-controlled field-effect transistor devices. Using the distinct carrier relaxation dynamics of excitons and trions of monolayer MoS as sensitive descriptors, an in situ microcell-based scanning time-resolved liquid cell microscope is set up to simultaneously measure the bias-dependent exciton/trion dynamics and spatially map the catalytic activity of monolayer MoS during the HER.

Topological Proximity-Induced Dirac Fermion in Two-Dimensional Antimonene.

Antimonene is a promising two-dimensional (2D) material that is calculated to have a significant fundamental bandgap usable for advanced applications such as field-effect transistors, photoelectric devices, and the quantum-spin Hall (QSH) state. Herein, we demonstrate a phenomenon termed topological proximity effect, which occurs between a 2D material and a three-dimensional (3D) topological insulator (TI). We provide strong evidence derived from hydrogen etching on SbTe that large-area and well-ordered antimonene presents a 2D topological state.

Atomic-Layer Controlled Interfacial Band Engineering at Two-Dimensional Layered PtSe/Si Heterojunctions for Efficient Photoelectrochemical Hydrogen Production.

Platinum diselenide (PtSe) is a group-10 two-dimensional (2D) transition metal dichalcogenide that exhibits the most prominent atomic-layer-dependent electronic behavior of "semiconductor-to-semimetal" transition when going from monolayer to bulk form. This work demonstrates an efficient photoelectrochemical (PEC) conversion for direct solar-to-hydrogen (H) production based on 2D layered PtSe/Si heterojunction photocathodes. By systematically controlling the number of atomic layers of wafer-scale 2D PtSe films through chemical vapor deposition (CVD), the interfacial band alignments at the 2D layered PtSe/Si heterojunctions can be appropriately engineered.

Generation of sub-half-cycle 10 µm pulses through filamentation at kilohertz repetition rates.

We have experimentally demonstrated the generation of sub-half-cycle phase-stable pulses with the carrier wavelength of 10.2 µm through two-color filamentation in nitrogen. The carrier-envelope phase (CEP) of the MIR pulse is passively stabilized and controlled by the attosecond time delay between the two-color input pulses.

Extremely Fast Optical and Nonvolatile Control of Mixed-Phase Multiferroic BiFeO via Instantaneous Strain Perturbation.

Multiferroics-materials that exhibit coupled ferroic orders-are considered to be one of the most promising candidate material systems for next-generation spintronics, memory, low-power nanoelectronics and so on. To advance potential applications, approaches that lead to persistent and extremely fast functional property changes are in demand. Herein, it is revealed that the phase transition and the correlated ferroic orders in multiferroic BiFeO (BFO) can be modulated via illumination of single short/ultrashort light pulses.

Generation and manipulation of polarization-twisting dual pulses with a high degree of freedom.

A polarization-twisting dual-pulse (PTDP) system is demonstrated using a modified Michelson interferometer (MI), in which a pellicle beam splitter is inserted into each arm. By tuning the positions of the end mirrors and pellicle beam splitters in the MI, the polarization-twisting frequency, the helicity, and the interval between two pulses can be individually manipulated. This PTDP generation system has a high degree of freedom in terms of tuning and has applications in the study of helicity dynamics in quantum matter, particularly in the terahertz (THz) regime.

The influence of the interfacial layer on the stability of all-solution-processed organic light-emitting diodes.

Improving the stability of large-area organic light-emitting diodes is very important for practical applications. The interfacial layer plays a crucial role to improve the electron injection characteristic. In this work, devices prepared by various solution-processed interfacial materials and thermal-evaporated CsF were compared.