A Non-Covalent Strategy for the Assembly of Supramolecular Photocurrent-Generating Systems

• Published in: Journal of the American Chemical Society 2003-03, Vol.125 (10), p.2838-2839
• Main Authors: Soto, Ernesto, MacDonald, John C, Cooper, Christopher G. F, McGimpsey, W. Grant
• Format: Article
• Language: English
• Subjects: Chemistry; Exact sciences and technology; General and physical chemistry; Solid-liquid interface; Surface physical chemistry
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja0289548

Three photocurrent-generating thin films were assembled on gold surfaces. SAM I was constructed from molecules consisting of an alkyl disulfide group linked covalently to a 12-residue helical peptide and terminated with an alanine residue containing a pyrene chromophore. SAM I served as a benchmark for multilayered films II and III in photocurrent generation experiments. Films II and III were assembled from several components that were linked noncovalently by metal−ligand complexation. Cyclic voltammetry and contact angle measurements suggest that the films consist of ordered layers with relatively few defects. Photoexcitation of SAM I by the output of a 350 nm lamp (∼0.2 mW power incident on the sample) results in current generation in the range 5−10 nA/cm2. Photoexcitation of II and III yields higher current in the range 10−30 nA/cm2, representing a quantum efficiency of ∼1%. The observation of comparable or higher current from noncovalently assembled multicomponent films indicates that this method of assembly may obviate the problems associated with the covalent assembly of devices from large molecules.