Jae Kyu Song

An oxygen-vacancy rich, bismuth oxyiodide-based Z-scheme 3D hierarchical MoS₂/BiOI/AgI ternary nanocomposite photocatalyst was fabricated using a simple precipitation process in ethylene glycol and water. The presence of oxygen-vacancies in BiOI and the two-dimensional nature of molybdenum disulfides in the composite prolongs the charge carrier lifetime through a Z-scheme system and enhances the performance of the photocatalyst for the degradation of rhodamine B. On the basis of effic

This work demonstrates a design strategy for CdS/MoS₂@Ni₂P as hydrogen production photocatalyst.

We report the unusual generation of near-IR electrochemiluminescence from orange fluorescent Au nanoclusters soluble in water.

The ultrafast lasing dynamics of single zinc oxide nanowires are studied by time-resolved upconversion of the lasing emission as a function of the ultraviolet excitation intensity. Induction times for stimulated emission in individual nanowires are observed to be 1−5 ps or 3−15 roundtrips for nominal 20 μm long nanowires, depending on the 267 nm excitation intensity. In separate experiments, transient absorption profiles are also obtained for time-delayed 800 and 400 nm pulses to elucidate the c

Efficient light harvesting and transfer of photogenerated charge carriers between the photoanode and the O2 evolution catalyst are crucial for robust photoelectrochemical (PEC) water splitting. Herein, we present a simple strategy to improve the light harvesting capability and the hole transfer efficiency by anchoring dithiooxamide-derived N, S co-doped carbon nanosheets (NSCN) as a visible-light harvester and polyaniline (PANI) as a hole transfer layer from BiVO4 to CoPi. The resultant BiVO4–NS

Solar-driven semiconductor-based molecular hydrogen production is an ideal protocol for converting abundant solar energy to green fuel. However, this process suffers from costly semiconductor nanostructures, low efficiency, and poor stability. Here, we design a noble-metal-free photocatalyst, CdS-NiFe layered double hydroxide (LDH) nanocomposite, which is synthesized using the liquid-phase pulsed-laser ablation and hydrothermal method. The nanocomposite has a unique morphology of 2D-NiFe LDH nan

Mass spectrometric and anion photoelectron spectroscopic studies of homogeneous naphthalene cluster anions, (Nph)n=2–7−, were conducted to characterize the nature of their anionic cores. The smallest stable species in this series was found to be the naphthalene dimer anion. The vertical detachment energies of naphthalene clusters, n=2–7, were determined and found to increase smoothly with cluster size. By extrapolation, the vertical detachment energy of the isolated naphthalene molecule was foun

The ultrafast lasing dynamics of single zinc oxide nanotetrapods and nanowires are investigated by two-color femtosecond excitation/optical injection spectroscopy. The transient spectral gain induced by time-delayed optical injection pulses (400 nm) is used to investigate the spectrally and temporally resolved lasing properties in a single tetrapod or nanowire laser excited by 267-nm pulses. The lasing output pulse exhibits a faster lasing decay time than the carrier decays due to the superlinea

Two-color and one-color resonance enhanced multiphoton ionization photoelectron spectroscopies (REMPI–PES) have been applied to Rydberg states (n=3) of jet-cooled pyrazine. The 3s and 3p members of Rydberg series converging to the ground state (n−1) of the cation and the 3s member of a Rydberg series converging to an excited state of the cation (π−1) were observed. The photoelectron angular distributions (PADs) measured via the 3s(n−1) state drastically differed for the two-color and one-color R

We studied the anion clusters of anthracene, Ann− (n=1–16), by mass spectrometry, photoelectron spectroscopy, and theoretical calculations. The magic numbers observed at n=5 and 13 indicated formation of the half-filled and completely-filled first solvation shell, respectively. We found that autodetachment could occur via a short-lived excited state of the anion, producing autodetached electrons at a nearly constant kinetic energy, irrespective of the photon energy. Three distinct forms of anion

Transition-metal dichalcogenide materials play a major role in the state-of-the-art innovations for energy conversion because of potential applications resulting from their unique properties. These materials additionally show inordinate potential toward the progress of hygienic power sources to deal with increasing environmental disputes at the time of skyrocketing energy demands. Herein, we report earth-abundant, few-layered, MoSe₂-bridged MoS₂/cadmium sulfide (CdS) nanoco

The urchin shaped Mo doped W₁₈O₄₉ greatly enhances the charge transfer and photocatalytic efficiencies.

We studied the energetics and character of electron binding in the pyrazine anion clusters by mass spectrometry, photoelectron spectroscopy, and theoretical calculations. The mass distribution showed that the minimum number of molecules in a neat cluster of pyrazine to form an anion was two, with a single pyrazine molecule incapable of accommodating an excess electron. On the other hand, even the addition of a very weak solvent such as Ar sufficed to bring the affinity level of pyrazine below th