Polarization State of Light Scattered from Quantum Plasmonic Dimer Antennas

Plasmonic antennas are able to concentrate and re-emit light in a controllable manner through strong coupling between metallic nanostructures. Only recently has it found that quantum mechanical effects can drastically change the coupling strength as the feature size approaches atomic scales. Here, we present a comprehensive experimental and theoretical study of the evolution of the resonance peak and its polarization state as the dimer–antenna gap narrows to subnanometer scale. We clearly can identify the classical plasmonic regime, a crossover regime where nonlocal screening plays an important role, and the quantum regime where a charge transfer plasmon appears due to interparticle electron tunneling. Moreover, as the gap decreases from tens of to a few nanometers, the bonding dipole mode tends to emit photons with increasing polarizability. When the gap narrows to quantum regime, a significant depolarization of the mode emission is observed due to the reduction of the charge density of coupled quantum plasmons. These results would be beneficial for the understanding of quantum effects on emitting-polarization of nanoantennas and the development of quantum-based photonic nanodevices

MAPbCl₃‑Mediated Decomposition Process to Tune Cl/PbI₂ Distribution in MAPbI₃ Films

Various methods have been developed to optimize the active layer of perovskite solar cells. To date, the introduction of excess PbI₂ and chlorine doping are two typical means. Herein, an ion exchange–decomposition process was designed to combine these two approaches. In this process, the I–Cl exchange and MACl sublimation occurred simultaneously at elevated temperature, resulting in a PbI₂-excess, Cl-doped perovskite film. This combined strategy could guarantee that as much chlorine as possible was doped into the perovskite crystal lattice, which enables the production of perovskite films with obviously reduced defect density and enhanced carrier diffusion length. Strikingly, the power conversion efficiency of the device is boosted from 17.17% to 20.15%

Ultrasensitive Tyrosinase-Activated Turn-On Near-Infrared Fluorescent Probe with a Rationally Designed Urea Bond for Selective Imaging and Photodamage to Melanoma Cells

Melanoma is a highly aggressive malignancy and early monitoring and diagnosis are challenging at present. Tyrosinase is overexpressed in melanoma and regarded as an important biological marker for diagnosis and treatment. Thus, the selective and sensitive detection of tyrosinase is of great significance. To date, a few fluorescent probes have been reported for the detection of tyrosinase <i>in vitro</i> or <i>in vivo</i>. However, a highly sensitive near-infrared probe for tyrosinase monitoring is still missing. In this study, the Gibbs free energy change of different urea bonds during spontaneous hydrolysis is analyzed with the aid of chemical thermodynamic computation. On the basis of this analysis, we modified the dye methylene blue with a rationally designed urea bond to specifically create a probe, called MB1, for rapid detection of tyrosinase. Our experimental results demonstrated that MB1 can serve as a highly sensitive near-infrared responsive fluorescent probe for the monitoring and bioimaging of tyrosinase. In addition, the activated MB1 probe can effectively kill melanoma cells by photodynamic therapy. Thus, the near-infrared probe has great potential for monitoring and treating melanoma

Table S2 from Long-term archives reveal shifting extinction selectivity in China's postglacial mammal fauna

Holocene and historical records for 34 Chinese mammal specie

Table S1 from Long-term archives reveal shifting extinction selectivity in China's postglacial mammal fauna

Holocene wild mammal databas

Ultrasensitive Size-Selection of Plasmonic Nanoparticles by Fano Interference Optical Force

In this paper, we propose a solution for the ultrasensitive optical selection of plasmonic nanoparticles using Fano interference-induced scattering forces. Under a Gaussian beam excitation, the scattering of a plasmonic nanoparticle at its Fano resonance becomes strongly asymmetric in the lateral direction and consequently results in a net transverse scattering force, that is, Fano interference-induced force. The magnitude of this transverse scattering force is comparable with the gradient force in conventional optical manipulation experiments. More interestingly, the Fano scattering force is ultrasensitive to the particle size and excitation frequency due to the phase sensitivity of the interference between adjacent plasmon modes in the particle. Utilizing this distinct feature, we show the possibility of size-selective sorting of silver and gold nanoparticles with an accuracy of about ±10 nm and silica-gold core–shell nanoparticles with shell thickness down to several nanometers. These results would add to the toolbox of optical manipulation and fabrication

Additional file 1: of Characterization of a novel bioflocculant from a marine bacterium and its application in dye wastewater treatment

The phylogenetic tree of bioflocculant-producing strain H-6. (TIFF 52 kb

Additional file 2: of Characterization of a novel bioflocculant from a marine bacterium and its application in dye wastewater treatment

Effects of temperature (a) and initial pH (b) on bioflocculant production. (TIFF 1522 kb

Carbene-Catalyzed Enantioselective Petasis-Like Alkenylation

The N-heterocyclic carbene (NHC)-catalyzed enantioselective Petasis-like alkenylation of o-hydroxycinnamaldehydes or hydroxyl-tethered α,β-unsaturated aldehydes with styryl, dienyl, or trienyl boronic acids is disclosed. This method involves the addition of π-system-containing boronic acids to NHC-bounded α,β-unsaturated acyl azoliums and allows access to divergent assembly of β-alkenyl substituted dihydrocoumarin and γ- and δ-lactones. DFT calculations suggest that an unprecedented zwitterionic intermediate and 1,4- or 1,5- migration of alkenyl groups play a crucial role in the reaction. More in-depth studies of orbital and noncovalent interaction analysis provide more detailed explanations for pathways and stereoselectivity control

The bacterial community composition in the two groups at phylum level (A) and genus level (B).

<p>OLH = High group, OLL = Low group. The relative abundance of Firmicutes*, <i>Pseudobutyrivibrio</i>*, and unidentified bacteria and <i>Prevotella</i> belonging to the family Paraprevotellaceae* was significantly different between the two groups, with * means the significance at <i>P</i><0.05.</p