How to distinguish between interacting and noninteracting molecules in tunnel junctions

Recent experiments demonstrate a temperature control of the electric conduction through a ferrocene-based molecular junction. Here we examine the results in view of determining means to distinguish between transport through single-particle molecular levels or via transport channels split by Coulomb repulsion. Both transport mechanisms are similar in molecular junctions given the similarities between molecular intralevel energies and the charging energy. We propose an experimentally testable way to identify the main transport process. By applying a magnetic field to the molecule, we observe that an interacting theory predicts a shift of the conductance resonances of the molecule whereas in the noninteracting case each resonance is split into two peaks. The interaction model works well in explaining our experimental results obtained in a ferrocene-based single-molecule junction, where the charge degeneracy peaks shift (but do not split) under the action of an applied 7-Tesla magnetic field. This method is useful for a proper characterization of the transport properties of molecular tunnel junctions.Comment: Main text: 7 pages, 5 figures; SI: 2 pages, 2 figures. Accepted to RSC Nanoscal

Electrostatic Control over Temperature-Dependent Tunneling across a Single Molecule Junction

Understanding how the mechanism of charge transport through molecular tunnel junctions depends on temperature is crucial to control electronic function in molecular electronic devices. With just a few systems investigated as a function of bias and temperature so far, thermal effects in molecular tunnel junctions remain poorly understood. Here we report a detailed charge transport study of an individual redox-active ferrocene-based molecule over a wide range of temperatures and applied potentials. The results show the temperature dependence of the current to vary strongly as a function of the gate voltage. Specifically, the current across the molecule exponentially increases in the Coulomb blockade regime and decreases at the charge degeneracy points, while remaining temperature-independent at resonance. Our observations can be well accounted for by a formal single-level tunneling model where the temperature dependence relies on the thermal broadening of the Fermi distributions of the electrons in the leads.Comment: 37 pages, 13 figure

Does renewable energy reduce per capita carbon emissions and per capita ecological footprint? New evidence from 130 countries

This study explores whether increasing renewable energy consumption can alleviate environmental pressures (per capita carbon emissions and per capita ecological footprint) and the heterogeneity of the effects of increasing renewable energy consumption on the environmental pressures of countries in different income groups. We analyze 130 countries and three income groups from 1992 to 2019 based on a panel threshold regression estimation approach. The results show that (i) There is a negative relationship between renewable energy consumption and per capita ecological footprint and per capita carbon emissions, indicating that renewable energy consumption alleviates environmental pressure. (ii) When renewable energy consumption increases, the negative effects of renewable energy on per capita ecological footprint and per capita carbon emissions become more significant. This means that the more renewable energy is developed, the more it helps to alleviate environmental pressure. (iii) The inhibitory effect of renewable energy consumption on per capita ecological footprint is more significant in low-income countries than in middle-income countries. This indicates that renewable energy is more effective in reducing environmental pressures in poor countries than in rich countries

Green tea catechin epigallocatechin gallate alleviates high‐fat diet‐induced obesity in mice by regulating the gut–brain axis

Abstract Plant polyphenols have gained attention in recent years because of their potential to alleviate obesity and metabolic syndrome, protect neurological function, and maintain intestinal function. Here, we evaluated the effect of green tea catechin epigallocatechin gallate (EGCG) to suppress obesity, alleviate intestinal inflammation, and regulate hypothalamic neurotransmitters in high‐fat diet mice. Obese male C57BL/6J mice were gavaged with 25, 50, or 100 mg/kg·body weight (bw) of EGCG or water per day for 6 weeks. The results demonstrated that EGCG significantly reduced bw, fat accumulation, and liver steatosis. EGCG also modulated hypothalamic neurotransmitters such as dopamine and 5‐HTP. Besides, EGCG attenuated the expression of colonic inflammatory factors and barrier damage, increased the gut microbial abundance such as genus Alloprevotella, reduced short‐chain fatty acids, and downregulated the transcription factors. The results suggest that EGCG may alleviate obesity and related metabolic disorders through gut–brain interaction

Matcha Green Tea Alleviates Non-Alcoholic Fatty Liver Disease in High-Fat Diet-Induced Obese Mice by Regulating Lipid Metabolism and Inflammatory Responses

Lately, matcha green tea has gained popularity as a beverage and food additive. It has proved to be effective in preventing obesity and related metabolic syndromes. However, the underlying mechanisms of its control effects against non-alcoholic fatty liver disease (NAFLD) are complicated and remain elusive. In the present study, we performed an in vivo experiment using male C57BL/6 mice fed with a high-fat diet and simultaneously treated with matcha for six weeks. Serum biochemical parameters, histological changes, lipid accumulation, inflammatory cytokines, and relevant indicators were examined. Dietary supplementation of matcha effectively prevented excessive accumulation of visceral and hepatic lipid, elevated blood glucose, dyslipidemia, abnormal liver function, and steatosis hepatitis. RNA sequencing analyses of differentially expressed genes in liver samples indicated that matcha treatment decreased the activity of lipid droplet-associated proteins and increased the activity of cytochrome P450 enzymes, suggesting improved metabolic capacity and liver function. The current study provided evidence for new dietary strategies based on matcha supplementation to ameliorate lipotoxicity-induced obesity and NALFD

Crystal structure of ethylenedioxytetrathiafulvalene-4,5-bis(thiolbenzoic acid) 0.25-hydrate

In the title compound (systematic name: 4,4′-{[2-(5,6-dihydro-[1,3]dithiolo[4,5-b][1,4]dioxin-2-ylidene)-1,3-dithiole-4,5-diyl]bis(sulfanediyl)}dibenzoic acid 0.25-hydrate), C22H14O6S6·0.25H2O, the tetrathiafulvalene (TTF) core adopts a boat conformation, where the central S2C=CS2 plane makes dihedral angles of 31.34 (4) and 26.83 (6)°, respectively, with the peripheral S2C=CS2 and S2C2O2 planes. In the crystal, the benzoic acid molecules are linked via O—H...O hydrogen bonds, forming inversion dimers with R22(8) motifs. The dimers are linked through weak C—H...O hydrogen bonds into a chain structure along [-101]. The chains stack along the a axis through S...S and S...C short contacts, forming layers parallel to the ac plane

In Operando Characterization and Control over Intermittent Light Emission from Molecular Tunnel Junctions via Molecular Backbone Rigidity

10.1002/advs.201900390Advanced Science620190039

Electrostatic Control Over Temperature-Dependent Tunnelling Across A Single-Molecule Junction

Understanding how the mechanism of charge transport through molecular tunnel junctions depends on temperature is crucial to control electronic function in molecular electronic devices. With just a few systems investigated as a function of bias and temperature so far, thermal effects in molecular tunnel junctions remain poorly understood. Here we report a detailed charge transport study of an individual redox-active ferrocene-based molecule over a wide range of temperatures and applied potentials. The results show the temperature dependence of the current to vary strongly as a function of the gate voltage. Specifically, the current across the molecule exponentially increases in the Coulomb blockade regime and decreases at the charge degeneracy points, while remaining temperature-independent at resonance. Our observations can be well accounted for by a formal single-level tunnelling model where the temperature dependence relies on the thermal broadening of the Fermi distributions of the electrons in the leads