Silver nanowire (Ag NW) networks have attracted wide attention as transparent electrodes for emerging flexible optoelectronics. However, the sheet resistance is greatly limited by large wire-to-wire contact resistances. Here, we propose a simple sunlight illumination approach to remarkably improve their electrical conductivity without any significant degradation of the light transmittance. Because the power density is extremely low (0.1 W/cm2, 1-Sun), only slight welding between Ag NWs has been observed. Despite this, a sheet resistance of <20 Ω/sq and transmittance of ~87% at wavelength of 550 nm as well as excellent mechanical flexibility have still been achieved for Ag NW networks after sunlight illumination for 1 hour or longer, which are significant upgrades over those of ITO. Slight plasmonic welding together with the associated self-limiting effect has been investigated by numerical simulations and further verified experimentally through varied solar concentrations. Due to the reduced resistance, high-performance transparent film heaters as well as efficient defrosters have been demonstrated, which are superior to the previously-reported Ag NW based film heaters. Since the sunlight is environmentally friendly and easily available, sophisticated or expensive facilities are not necessary. Our findings are particularly meaningful and show enormous potential for outdoor applications.

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We propose a polarization-insensitive and high-efficiency plasmonic silicon Schottky diode for detection of sub-bandgap photons in the optical communication wavelength range through internal photoemission. Our photodiode is based on a hybrid plasmonic silicon waveguide. It has a gold film covering both the top and the sidewalls of a dielectric silicon waveguide with the Schottky contact formed at the gold-silicon interface. An extensive physical model is presented in detail and applied to calculate and analyze the performance of our detector. By comparison with a diode with only top contact of gold, the polarization sensitivity of responsivity is greatly minimized in our photodetector with sidewall coverage of gold.Much higher responsivities for both polarizations are also achieved in a very broad wavelength range of 1.2-1.5 μm. Moreover, the Schottky contact is only 4 μm long, leading to a very small dark current. Our design is very promising for practical applications in high-density silicon photonic integration.Internal photoemission (IPE) is an intrinsic property of a Schottky diode, occurring at a metal-semiconductor interface [1]. In IPE, three processes are involved.Firstly, an electron (hole) in the metal is excited to a higher level after absorbing a photon, becoming a hot electron (hot hole). Secondly, the hot carrier (electron or hole) travels to the metal-semiconductor interface. During its travel, the hot carrier may lose some energy due to scattering by cold carriers or by thermal relaxation. Finally, upon

A facile polymethyl methacrylate-assisted turnover-transfer approach is developed to fabricate uniform hexagonal gold nanobowl arrays. The bare array shows inferior light trapping ability compared to its inverted counterpart (a gold nanospherical shell array). Surprisingly, after being coated with a 60-nm thick amorphous silicon film, an anomalous light trapping enhancement is observed with a significantly enhanced average absorption (82%), while for the inverted nanostructure, the light trapping becomes greatly weakened with an average absorption of only 66%. Systematic experimental and theoretical results show that the main reason for the opposite light trapping behaviors lies in the top amorphous silicon coating, which plays an important role in mediating the excitation of surface plasmon polaritons and the electric field distributions in both nanostructures.

Granite exhibits obvious meso-geometric heterogeneity. To study the influence of grain size and preferred grain orientation on the damage evolution and mechanical properties of granite, as well as to reveal the inner link between grain size‚ preferred orientation, uniaxial tensile strength (UTS) and damage evolution, a series of Brazilian splitting tests were carried out based on the combined finite-discrete element method (FDEM), grain-based model (GBM) and inverse Monte Carlo (IMC) algorithm. The main conclusions are as follows: (1) Mineral grain significantly influences the crack propagation paths, and the GBM can capture the location of fracture section more accurately than the conventional model. (2) Shear cracks occur near the loading area, while tensile and tensile-shear mixed cracks occur far from the loading area. The applied stress must overcome the tensile strength of the grain interface contacts. (3) The UTS and the ratio of the number of intergrain tensile cracks to the number of intragrain tensile cracks are negatively related to the grain size. (4) With the increase of the preferred grain orientation, the UTS presents a “V-shaped” characteristic distribution. (5) During the whole process of splitting simulation, shear microcracks play the dominant role in energy release; particularly, they occur in later stage. This novel framework, which can reveal the control mechanism of brittle rock heterogeneity on continuous-discontinuous trans-scale fracture process and microscopic rock behaviour, provides an effective technology and numerical analysis method for characterizing rock meso-structure. Accordingly, the research results can provide a useful reference for the prediction of heterogeneous rock mechanical properties and the stability control of engineering rock masses.