Leakage radiation spectroscopy of organic nanofibers on metal films: evidence for exciton-surface plasmon polariton interaction

摘要

Leakage radiation spectroscopy of organic nanofibers composed of self-assembled organic molecules (para-Hexaphenylene,p-6P) deposited on a thin (40-60 nm) Ag film has been performed in the spectral range 420-675nm which overlaps with the nanofiber photoluminescence band. Using a soft transfer technqiue, domains ofmutually parallel oriented organic nanofibers were initially grown under high-vacuum conditions by molecularbeamepitaxy onto a cleaved muscovite mica substrate and afterwards transferred onto a silver film prepared onthe glass carrier. The sample placed on a flat side of a hemisphere prism with an index matching liquid wasilluminated by either a He-Cd 325 nm laser or by white light from a bulb. In the case of laser excitation twoorthogonal linear polarizations and two different configurations of p-6P nanofibers were applied, both parallel andperpendicular to the plane of detection. The leakage radiation was observed on the opposite side of the Ag filmat the phase matching angle. The spectrally resolved intensity of the scattered radiation has been measured as afunction of scattering angle at normally incident light. The spectrum contains a distinct peak at an wavelengthdependent angle above the critical angle. By analyzing this dispersion curve one can argue that it originatesfrom the interaction between the nanofiber excitons and surface plasmon polaritons of the metal film.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.