Synthesis, aggregation and photoconductive properties of alkoxycarbonyl substituted perylenes

A series of 3,4,9,10-tetra-(n-alkoxy-carbonyl)-perylene (PTAC, n = 4, 6, 8, 10, 12) derivatives with various alkyl chains were synthesized via a simple and efficient phase-transfer catalysis method. It was found that the length of the alkyl chains attached to the perylene skeleton greatly influenced aggregation behaviour. The finding that it was easier for PTAC derivatives with shorter alkyl chains to form crystal films was interpreted in terms of molecular volume and steric repulsion. The photoconductivity of the materials was investigated by xerographic photoinduced discharge technique and the results showed that photosensitivity increased with the decreasing length of the alkyl chain attached to perylene core. This result was consistent with the changing trend of aggregate structure observed for the PTAC derivatives used in this study: the shorter the substituted alkyl chain, the more ordered the film was and, thus, the greater was the photosensitivity.