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The nanoparticle density (PD) of the substrates is crucial for surface‐enhanced Raman scattering (SERS) performance. Here, bottom‐up SERS substrates based on rough gold nanorods (R‐Au NRs) with different PD are fabricated and their SERS property are investigated. In particular, R‐Au NRs are deposited on the Si wafer from sparse to dense through electrostatic interaction and from monolayer to multiple layers by interface self‐assembly technique. It is found that the SERS intensity increases dramatically with increasing PD and remains almost unchanged when the PD increases to 241.22 counts µm−2, and the limited penetration depth of laser is the reason for the intensity saturation. Additionally, similar results are observed in the smooth Au NRs substrates, re‐confirming the PD‐dependent SERS performance. Importantly, the SERS activity of R‐Au NRs substrates is higher than smooth Au NRs substrates in each PD, indicating that R‐Au NRs can produce stronger electromagnetic field enhancement, which is supported by the theoretical simulation results. Finally, it is demonstrated that the optimal SERS substrates can be effectively utilized for the quantitative measurement of thiram in soil. Briefly, the PD of substrates has a great impact on SERS activity, which offers an idea for the design of highly efficient SERS substrates. [ABSTRACT FROM AUTHOR]

Antimony selenide (Sb2Se3) is an emerging photovoltaic material. We demonstrate that PbI2 is an effective p-type dopant for Sb2Se3. The Sb2Se3 film was doped by PbI2 by thermal diffusion. Both the hole concentration and conductivity are dramatically increased by doping. We fabricated the Sb2Se3 solar cell using C60 as an electron transport layer by vacuum thermal evaporation. By PbI2 doping, the open-circuit voltage (Voc) is increased from 0.32 to 0.38 V, and the power conversion efficiency is improved from 2.87% to 4.43%. This work provides an effective p-type dopant for Sb2Se3. [ABSTRACT FROM AUTHOR]

The concave star-shaped Au nanocrystals with ten sharp tips endowed them with 12-fold higher SERS enhancements than Au nanospheres. • Au nanocrystals with sharp tips were prepared using pentatwinned Au NSs as seed. • Au nanocrystals provided a broad spectral range from VIS to NI region. • Monolayers of Au nanocrystals displayed strong shape-dependent SERS activity. • Concave nanostars was 12-fold higher SERS enhancement than Au NSs. In this work, various geometries of Au nanocrystals with sharp tips including decahedra, concave star, and spindle were synthesized through Ag underpotential deposition-dominated growth approach based on utilizing a novel type of Au nanoseed (i.e., pentatwinned Au nanospheres). These as-prepared Au nanocrystals exhibited a broad localized surface plasmon resonance (LSPR) tunability from visible to near-infrared region. Furthermore, we fabricated the monolayer film based on Au nanocrystals with different morphologies through liquid/liquid interface self-assembly technique, which displayed strong shape-dependent surface enhanced Raman scatting (SERS) performance. More significantly, concave star-shaped Au nanocrystals with ten sharp tips endowed them with 12-fold higher SERS enhancements than Au nanospheres, which was in line with the simulation results by finite difference time domain (FDTD) method. Our study provides a novel route for fabrication of Au nanocrystals with diversified structures, and the efficient SERS substrates have great prospect for the applications in ultrasensitive chemical and biological sensing. [ABSTRACT FROM AUTHOR]

The FH2– anion has a stable structure that resembles a configuration in the vicinity of the transition state for neutral reaction F + H2 → HF + H. Electron photodetachment spectra of the FH2– anion reveal the neutral reaction dynamics in the critical transition-state region. Accurate quantum dynamics simulations of the photodetachment spectra using highly accurate new ab initio potential energy surfaces for both anionic and neutral FH2 are performed and compared with all available experimental results. The results provide reliable interpretations for the experimental observations of FH2– photoelectron detachment and reveal a detailed picture of the molecular dynamics around the transition state of the F + H2 reaction. The latest high-resolution photoelectron detachment spectra [Kim et al. Science, 2015, 349, 510-513] confirm the high accuracy of our new potential energy surface for describing the resonance-enhanced reactivity of the neutral F + H2 reaction.