Плазмонная активация и тушение люминесценции растворов полифениленвинилена (MEH-PPV) одно- и двустенными углеродными нанотрубками

Abstract

Spectral-luminescent properties of benzene and toluene solutions of poly[2-methoxy, 5-(2’- ethylhexyloxy)-1,4-phenylene-vinylene] (MEH-PPV) with additives of single - and double-walled carbon nanotubes (CNTS) were studied in order to detect manifestations of plasmon properties of CNTS in the luminescence of MEH-PPV solutions. It was found that the dependence of the luminescence intensity of the polymer solution on the CNT concentration is non-monotonic: with an increase in the number of dissolved nanotubes, this intensity initially increases, and then decreases. At the same time, the deformation of the light spectrum itself practically does not take place. The effect was observed as when using a single-walled CNT (swcnt) and double wall (DWNT). The depth of modulation of the glow intensity in the case of DPT was higher than in the case of ount. To explain the observed dependencies, various variants of the electro-dynamic model of activation-quenching of MEH-PPV luminescence by carbon nanotubes are proposed. Direct modeling of near and far field characteristics is performed based on Maxwell's equations, for numerical solution of which the finite difference method in the time domain (FDTD) is used. Computational experiments have shown that CNTS with a MEH-PPV layer have directional antenna properties, acting as a kind of waveguides. Thus, the energy of radiation that reached the far zone in the direction of the nanotube axis was an order of magnitude higher than in the case of a solution without CNT. Fan-type electromagnetic waves emanating from both ends of the nanotube were detected, as well as the stage of plasmon waves beating, which characterizes the nanotube as a waveguide. Molecular dynamic modeling of the configurations of the adsorbed MEH-PPV chain in various solvents, both on a single CNT and on two parallel CNTS with a variation in the distance between them, was performed. It was found that as the distance between CNTS increases, the conformational structure of MEH-PPV becomes more loose: there is an increase in the number of large loops of the macrocycle in the bulk phase of the solution