Photoluminescence of pentacene solutions in n-pentyl-n-cyanobiphenyl

Abstract

We investigated photoluminescence (PL) spectra of pentacene (Pc) in the liquid- and solid-crystalline n-pentyl-n´-cyanobiphenyl (5CB) matrices. It was shown that the liquid-crystalline matrix behaves as a polar solvent relatively to Pc. Pc and 5CB molecules can form loosely bound donor-acceptor complexes. These complexes may be characterized with their PL spectrum and lifetime that are different from those of molecular Pc. Being heated up to 343 K these complexes are broken down, and Pc molecular radiation is observed in the PL spectra of solutions.