The ZnO/Cu2O heterojunction promises high efficiency in photocurrent conversion and other light-driven processes, but the lattice mismatch between ZnO and Cu2O leads to slow electron transfer and low conversion efficiency. In addition, the stability of Cu2O is still the main challenging and limiting factor for device applications in real environments. Cu x O is a mixed semiconductor of CuO and Cu2O, which is a promising alternative to Cu2O in device fabrication due to its better stability and photocatalytic efficiency. In this work, Cu x O nanorods were attached to vertically aligned gold-decorated ZnO nanorods, creating a hierarchical ZnO/Au/Cu x O nanoforest. In addition, the hierarchical surface shows superhydrophobicity, which can prevent Cu2O degradation by water and oxygen. Femtosecond time-resolved transient absorption spectroscopy was employed to investigate the electron transfer dynamics in the ZnO/Au/Cu x O heterojunction. The nanoforest demonstrates enhanced electron mobility, increased lattice match, and higher photocurrent conversion efficiency compared with bare ZnO, Cu x O, or ZnO/Cu x O.

The matrix-isolated infrared spectrum of a hydrogen cyanide–methyl chloride complex was investigated in a solid argon matrix. HCN and CH3Cl were co-condensed onto a substrate held at 10 K with an excess of argon gas, and the infrared spectrum was measured using Fourier-transform infrared spectroscopy. Quantum chemical geometry optimization, harmonic frequency, and natural bonding orbital calculations indicate stabilized hydrogen- and halogen-bonded structures. The two resulting weakly bound complexes are both composed of one CH3Cl molecule bound to a (HCN)3 subunit, where the three HCN molecules are bound head-to-tail in a ring formation. Our study suggests thatin the presence of CH3Clthe formation of (HCN)3 is promoted through complexation. Since HCN aggregates are an important precursor to prebiotic monomers (amino acids and nucleobases) and other life-bearing polymers, this study has astrophysical implications toward the search for life in space.

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Hydrogen cyanide (HCN) is a molecule of importance in astrochemistry. To prepare for experiments to study its reactivity, we selectively produced a molecular beam of monomeric HCN using a cryogenic buffer-gas source. The HCN beam was first interrogated by condensing it on a 10K substrate using argon as a bath gas to create an inert matrix. Based on a comparison of the resulting infrared spectrum with experiments that use conventional effusive sources, HCN polymers can be nearly eliminated from the matrix using a cryogenic buffer-gas beam source. Our experiments suggest that HCN undergoes polymerization in the gas phase and may exist, to some extent, as a dimer under ambient conditions. We will discuss further investigations using continuous-wave cavity ringdown spectroscopy to examine the first vibrational overtone of the alkynyl C-H stretch of HCN monomer and dimer in the near infrared.