Synthesis and photogeneration properties of copolyacrylate having carbazole donor and trinitrofluorenone acceptor chromophores

Novel copolymers containing both donor and acceptor chromophores have been synthesized by free radical polymerization of 2-N-carbazolylethyl acrylate and 2′-acrylylethyl-4,5,7-trinitrofluorenone-2-carboxylate. The charge transfer complexation occurs in copolymers in a similar way to poly(2-N-carbazolylethyl acrylate) molecularly doped with 2,4,7-trinitrofluorenone (TNF) and a model compound, ethyl 4,5,7-trinitrofluorene-2-carboxylate (Et-TNF). Copolymer and doped systems exhibit obvious CT bands in a 440–600 nm region, where the former shows higher absorption than the latter. Glass-transition temperatures show positive deviations from the weight-average values of copolymers, indicating the partial interchain interaction of copolymers in solid state. Quantum efficiency of hole photogeneration of the copolymer with the 0.05 to 1.0 molar ratio of TNF to carbazole chromophores is higher than those of the corresponding molecularly TNF- and Et-TNF-doped poly(2-N-carbazolylethyl acrylate), especially at lower electric fields.