A two-dimensional (2D) porous layer can make an ideal membrane for separation of chemical mixtures because its infinitesimal thickness promises ultimate permeation. Graphene--with great mechanical strength, chemical stability, and inherent impermeability--offers a unique 2D system with which to realize this membrane and study the mass transport, if perforated precisely. We report highly efficient mass transfer across physically perforated double-layer graphene, having up to a few million pores with narrowly distributed diameters between less than 10 nanometers and 1 micrometer. The measured transport rates are in agreement with predictions of 2D transport theories. Attributed to its atomic thicknesses, these porous graphene membranes show permeances of gas, liquid, and water vapor far in excess of those shown by finite-thickness membranes, highlighting the ultimate permeation these 2D membranes can provide.

It has been claimed that graphene growth on copper by chemical vapor deposition is dominated by crystallization from the surface initially supersaturated with carbon adatoms, which implies that the growth is independent of hydrocarbon addition after the nucleation phase. Here, we present an alternative growth model based on our observations that oppose this claim. Our Gompertzian sigmoidal growth kinetics and secondary nucleation behavior support the postulate that the growth can be controlled by adsorption-desorption dynamics and the dispersive kinetic processes of catalytic dissociation and dehydrogenation of carbon precursors on copper.

We extend the model of Chance, Prock and Silbey [1] and analytically determine the Poynting vector in the direction perpendicular to the plane of a multilayer organic device. The result is used to predict the spatial profile of Förster energy transfer, the radiative output of an organic light emitting device, and to calculate the efficiency of surface plasmon polariton-mediated energy transfer across a thin silver film.

The performance of a phthalocyanine-based photovoltaic is boosted in the absorption gap between the phthalocyanine Q and Soret bands. Light absorption is decoupled from exciton diffusion using a light absorbing "antenna" layer external to the conventional charge generating layers. Radiation absorbed by the antenna is transferred into the charge generating layers via surface plasmon polaritons in an interfacial thin silver contact. The peak efficiency of energy transfer is measured to be at least ͑51± 10͒%.

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