Shaping and polarizing fluorescence emission of a polycrystalline organic semiconductor film by plasmonic nanogratings

Abstract

The fluorescence emission properties of hybrid systems consisting of a one-dimensional gold nanowire grating and an evaporated thin film of the small molecule organic semiconductor diindenoperylene (DIP) are investigated. The optical properties of the metallic systems are dominated by their plasmonic resonances. The spectral positions of the resonances are tuned through the width of the single nanowires. Additionally, the plasmonic gratings show a strong polarization dependency due to their one-dimensionality. In contrast, the pure organic system has a polarization-independent emission between 570 and 900 nm when excited with blue light, whereas no photoluminescence can be detected from the bare plasmonic system for the same illumination conditions. For the hybrid system, the intensity, the shape of the emission spectrum, and the polarization of the emission clearly correlate with the optical properties of the plasmonic nanowires. Depending on the optical properties of the plasmonic system, different emission bands of the organic thin film can be enhanced.