The hydrogen bond represents a fundamental interaction widely existing in nature, which plays a key role in chemical, physical and biochemical processes. However, hydrogen bond dynamics at the molecular level are extremely difficult to directly investigate. Here, in this work we address direct electrical measurements of hydrogen bond dynamics at the single-molecule and single-event level on the basis of the platform of molecular nanocircuits, where a quadrupolar hydrogen bonding system is covalently incorporated into graphene point contacts to build stable supramolecule-assembled single-molecule junctions. The dynamics of individual hydrogen bonds in different solvents at different temperatures are studied in combination with density functional theory. Both experimental and theoretical results consistently show a multimodal distribution, stemming from the stochastic rearrangement of the hydrogen bond structure mainly through intermolecular proton transfer and lactam–lactim tautomerism. This work demonstrates an approach of probing hydrogen bond dynamics with single-bond resolution, making an important contribution to broad fields beyond supramolecular chemistry.

Alpha-fetoprotein (AFP) is widely-known as the most commonly used protein biomarker for liver cancer diagnosis at the early stage. Therefore, developing the highly sensitive and reliable method of AFP detection is of essential demand for practical applications. Herein, two types of aptamer-based AFP detection methods, i.e., optical and electrochemical biosensors, are reviewed in detail. The optical biosensors include Raman spectroscopy, dual-polarization interferometry, resonance light-scattering, fluorescence, and chemiluminescence. The electrochemical biosensors include cyclic voltammetry, electrochemical impedance spectroscopy, and giant magnetic impedance. Looking into the future, methods for AFP detection that are high sensitivity, long-term stability, low cost, and operation convenience will continue to be developed.

Localized surface plasmon resonance (LSPR) has been applied in photovoltaic devices to improve their photoelectric conversion efficiency. In this study, the mechanism of LSPR in dye-sensitized solar cells (DSSCs) was determined. Specifically, silver nanoparticles were formed by evaporating silver in electro-beam equipment and then annealing it in a tube furnace. The sizes of the nanoparticles varied with the changes in their thicknesses during evaporation and annealing. A DSSC-based graphene was designed to consist of different sizes of metal nanoparticles assembled on a cathode electrode. The photon electric performance of the DSSCs, which depended on Ag nanoparticles, was analyzed in detail, with a particular focus on nanoparticle size. Compared with the DSSC without Ag nanoparticles, the DSSC with LSPR exhibited excellent electric current density and incident photon-to-current efficiency (IPCE) performance due to the LSPR effect. The DSSC assembled with 10 nm-thick Ag film and annealed to form nanoparticles exhibited a high IPCE of 70.03%. The IPCE value of this DSSC was 45.15% higher than that of the pure graphene-based DSSC (31.62%). However, Ag nanoparticles increased to a certain degree and became aggregated and concatenated, thereby decreasing the LSPR effect on DSSCs. Therefore, LSPR plays an important role in the photon-electrical performance of DSSCs.

The formation of various deep silicon structures using plasma etching has wide applications in sensors, micro-electro-mechanical systems and 3D wafer level integration. However, the fabrication of silicon cavities with high accuracy at depth within a large wafer size is still a challenge due to the large amount of etching required. Herein, silicon cavity etching uniformity approaching 3% in a depth of ~100 µ m on a 12-inch wafer is achieved through tuning the focus ring height, baffle shape, double zone helium cooling system and chamber pressure. The simulation of the electromagnetic field and gas flow field separately provides the guidance for the improvement, and the way in which the wafer temperature influences the etch uniformity is demonstrated. These results have significance for both the understanding of the plasma etching mechanism and the practical application of the silicon etching process for advanced device fabrication.