Rectification in molecular assemblies of donor–acceptor monolayers

We report molecular rectification based on donor/acceptor (D/A) assemblies. A monolayer of a donor and a monolayer of an acceptor have been bound electrostatically to fabricate a D/A assembly. While neither of the donor or the acceptor monolayer showed any rectification, the D/A assembly showed asymmetric current–voltage characteristics. Molecular rectification in a D/A assembly has been discussed in terms of a band diagram. The advantages of a D/A assembly over unimolecular D–σ–A, where complex chemical synthesis is involved, have been discussed. In this Letter, we have used a monolayer of a phthalocyanine and Rose Bengal as donor and acceptor, respectively.