Understanding the relaxation and injection dynamics of hot electrons is crucial to utilizing them in photocatalytic applications. While most studies have focused on carrier at metal/semiconductor interfaces, we study situ direct electron from metal adsorbates. Here, report a electron-driven hydrogen evolution reaction (HER) by exciting localized surface plasmon resonance (LSPR) Au grating photoelectrodes. In ultrafast transient absorption (TA) measurements show depletion peak resulting...

By discharging nanosecond high-voltage pulses in CO2-saturated water, we observe CO2 reduction to higher-order hydrocarbons, including acetic acid, formic and oxalate. Here, the plasma emission spectra exhibit Swan bands, which correspond C2 species, indicating that addition reducing CO2, C2-species are formed, presents possibility of converting a notorious greenhouse gas into liquid (i.e., dense) hydrocarbon fuels. In order characterize various products formed this process, cryogenic NMR...

We present the novel use of surface-enhanced Raman scattering spectroscopy to detect charge transfer in ferrocene/ferrocenium (Fc/Fc+) bound an active electrode under electrochemical working conditions. Ferrocene has a 6-carbon linker with thiol tether (6-(ferrocenyl)hexanethiol) and produces Fc/Fc+ couple voltammograms exhibiting above 0.4 V versus Ag/AgCl. By observing situ micro-Raman water immersion lens, we observe significant changes spectra that correspond state oxidation ferrocenium...

We demonstrate the hot electron injection of photoexcited carriers in an Ag-based plasmon resonant grating structure. By varying incident angle irradiation, sharp dips are observed reflectance with p-polarized light (electric field perpendicular to lines) when there is wavevector matching between and modes no dependence s-polarized light. This configuration enables us compare photoelectrochemical current produced by excitation that bulk metal interband absorption simply rotating polarization...

In situ surface-enhanced Raman scattering (SERS) spectroscopy is used to identify the key reaction intermediates during plasma-based removal of NO and SO2 under dry wet conditions on Ag nanoparticles. Density functional theory (DFT) calculations are confirm experimental observations by calculating vibrational modes surface-bound intermediate species. Here, we provide spectroscopic evidence that plasma increases NOx through formation highly reactive OH radicals, driving reactions H2SO4 HNO3,...

We report the electrochemical potential dependence of photocatalysis produced by hot electrons in plasmon-resonant grating structures. Here, corrugated metal surfaces with a period 520 nm are illuminated 785 wavelength laser light swept as function incident angle. At angles corresponding to excitation, we observe sharp peaks photocurrent and dips photoreflectance consistent conditions under which there is wavevector matching between spacing lines grating. In addition bare plasmonic surface...

We report electrochemical measurements using in situ Raman spectroscopy at graphene/D

By discharging nanosecond high-voltage (5 kV) pulses across an insulating substrate containing Au, Pt, or Cu nanoparticles, a 3 order of magnitude (1000×) enhancement in the generation plasma can be achieved through local field on surface nanoparticles. The low-temperature nature this transient is crucial to maintaining structural integrity these delicate These nanoparticles provide up 1000-fold plasma, which localized where it potentially useful (e.g., for catalysis). We performed both...

We report spectroscopic measurements of the local electric field using vibrational Stark shifts napthyl nitrile-functionalized silicon under electrochemical working conditions. The C≡N bond is particularly sensitive to applied fields and serves as a good probe for at silicon–aqueous interface. Here, surface-enhanced Raman spectra (SERS) are collected surface water immersion lens function reference potential in three-terminal potentiostat. In deionized (DI) KCl solutions, nitrile (i.e., C≡N)...

We explore the effect of charge density wave (CDW) on in-plane thermoelectric transport properties (PbSe)1+δ(VSe2)1 and (PbSe)1+δ(VSe2)2 heterostructures. In we observe an abrupt 86% increase in Seebeck coefficient, 245% power factor, a slight decrease resistivity over CDW transition. This behavior is not observed rather unusual compared to general trend other materials. The transition causes deviation from Mott relationship through correlated electron states. Raman spectra material show...

Metallic grating structures have been shown to provide an effective platform for generating hot electrons and driving electrochemical reactions. Here, we present a systematic theoretical study of the surface plasmon resonance in different corrugated metallic using computational electromagnetic tools (i.e., finite difference time domain (FDTD) method). We identify corrugation parameters that produce maximum resonant field enhancement at commonly used wavelengths photocatalytic applications...

We report hot electron-enhanced plasma generation by irradiating metal nanostructures with laser light. Here, a high-voltage nanosecond pulse is discharged across two electrodes interspersed nanoparticles (e.g., Au and Pt) both without excitation. With excitation (532 nm in wavelength), we observe 200-fold increase the emission intensity (i.e., density) lower threshold for onset of discharge voltage). This enhancement emission/discharge occurs reasons. First, electrons photoexcited these...

We demonstrate a more than 50-fold enhancement in the upconversion of methane to higher order hydrocarbons by discharging nanosecond-pulsed plasma across Au nanoparticles. Here, occurs as result local field provided The transient nature pulsed enables structure these delicate nanoparticles be preserved during discharge producing low-temperature plasma. Plasma emission spectroscopy shows signatures C2 Swan bands with and without presence Mass spectrometry demonstrates that is converted into...

We demonstrate a substantial modulation of the optical properties multilayer graphene (∼100 layers) using simple device consisting graphene/polymer electrolyte membrane/gold film stack. Applying voltage 3–4 V drives intercalation anion [TFSI]− [ion liquid diethylmethyl(2-methoxyethyl)ammonium bis(trifluoromethylsulfonyl)imide [DEME][TFSI]] resulting in reversible this optically dense material. Upon intercalation, we observe an abrupt shift 35 cm−1 G band Raman mode, increase FTIR reflectance...

We report Raman spectra and infrared (IR) imaging collected during the intercalation–deintercalation half cycles in a multilayer graphene (MLG) device (∼100 layers) operating at 0.2–10 Hz. The consists of MLG/alumina membrane/copper stack, which alumina membrane is filled with ionic liquid [DEME][TFSI], forming an electrochemical cell. Upon application positive voltage, TFSI– anions intercalate into interstitial spaces MLG. incident laser light modulated using optical chopper wheel that...

We have used surface plasmon resonant metal gratings to induce and probe the dielectric response (i.e., electro-optic modulation) of ionic liquids (ILs) at electrode interfaces. Here, cross-plane electric field modulates refractive index IL due Pockels effect. This is observed as a shift in angle grating Δϕ), which can be related change local refraction electrolyte Δnlocal). The reflection modulation compared against polar (D2O) non-polar solvent (benzene) confirm origin resonance shift....

We report a new approach for fabricating gate-tunable thermal emissivity surfaces by spraying them on graphene ink. The devices consist of multilayer (MLG)/porous alumina membrane/gold stack, in which the MLG is deposited ink onto porous membrane using an airbrush. consists μm-sized flakes suspended solution polyvinylpyrrolidone and ethylene glycol. filled with ionic liquid [DEME][TFSI], forming electrochemical cell. When positive voltage applied to device, intercalation [TFSI]- anions...

Because of the high dielectric strength water, it is extremely difficult to discharge plasma in a controllable way aqueous phase. By using lithographically defined electrodes and metal/dielectric nanoparticles, we create electric field enhancement that enables liquid electrolytes at significantly reduced applied voltages. Here, use voltage (10–30 kV) nanosecond pulse (20 ns) discharges generate transient An electrode geometry with radius curvature approximately 10 μm, gap distance 300 an...

Silicon-vacancy defects have been identified as a promising optical transition for quantum communications, control, and information processing. In the work presented here, we demonstrate voltage-controlled mechanism by which photoluminescent (PL) emission from silicon-vacancy (Si-V) in diamond can be modulated. particular, selectively produce negatively charged state of this defect (i.e., Si-V−), exhibits narrow (Γ = 4 nm) at 738 nm low laser power. This approach uses high voltage (2–5 kV)...

Nitrogen-vacancy (NV) and silicon-vacancy (SiV) color defects in diamond are promising systems for applications quantum technology. The NV SiV centers have multiple charge states, their states different electronic, optical spin properties. For the centers, most investigations sensing targeted on negatively charged (NV$^{-}$), it is important to be NV$^{-}$ state. However, known that converted neutrally state (NV$^{0}$) under laser excitation. An energetically favorable depends local...

Abstract Nitrogen-vacancy (NV) and silicon-vacancy (SiV) color defects in diamond are promising systems for applications quantum technology. The NV SiV centers have multiple charge states, their states different electronic, optical spin properties. For the centers, most investigations sensing targeted on negatively charged (NV − ), it is important to be state. However, known that converted neutrally state 0 ) under laser excitation. An energetically favorable depends local environments. It...

This study evaluates the beneficial effects of discharging nanosecond pulse transient plasma (NPTP) in a coaxial electrostatic precipitator for capturing nanoscale soot particles (∼50 nm) produced by an ethylene flame.