Photoluminescence of Solution Processed Poly n-Vinyl Carbazole Films

The photoluminescence (PL) of poly n-vinyl carbazole (PVK) films formed by solution processing was investigated. PVK films were formed by spincasting onto bare glass or glass covered by films of indium tin oxide (ITO) and poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate)ethylene (PEDOT : PSS). Some of the spincast films were redissolved in chloroform solvent and redried both in the absence or presence of an electric field (6000 V/cm). The broad. aggregate PL peak near 410 nm exhibited both blue and red shifts dependent upon the processing conditions. These shifts in PL were attributed to changes in the excimer populations associated with die molecular conformation of adjacent carbazole groups. The PL data were deconvoluted into two component peaks representing two excimers associated with overlap of only one (partial or P) or full overlap (F) of both aromatic rings on adjacent carbazole groups. It was concluded that the excimer population was dependent on the amount of residual solvent left in the film after processing and upon the type of substrate. The mechanism(s) controlling the molecular configurations was discussed. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 1-9, 2009