Photoactive ionic assemblies between n dopable perylene and p dopable carbazole derivatives

The study of molecular assemblies obtained by ionic interactions between two pi-conjugated organic molecules one possessing electron donor properties and the other possessing electron acceptor properties is discussed here. The electron acceptor molecules chosen are two tetra-chlorinated 3,4,9,10-perylene tetracarboxylic diimides bearing pyridine or amine functions ((1) or (2)) and the electron donor is 4-carbazol-9-yl-butane-l-sulfonic acid (3). The electrochemical characterizations and UV-vis/photoluminescence spectroscopy studies of each compound were realized. Moreover, photoluminescence quenching of (1) and (2) solutions is observed when they are protonated with the acid function of (3). Interestingly, with a simple mixture of (1) or (2) with 9-ethyl-carbazole, (1) and (2) solutions fluorescence quenching is very low. Finally, the relative energy levels values of the HOMO and LUMO of (1)-(3) were estimated and the results are compatible with a possible electron transfer from carbazole to perylene unit making these ionic assemblies attractive candidate for an active layer application in solar cell devices. (c) 2006 Elsevier B.V. All rights reserved.