Effect of Cross-linking on the Performance and Stability of Photocatalytic Photosystem I Films
By Yang, Siyuan; Robinson, Maxwell T.; Mwambutsa, Faustin; Cliffel, David E.; Jennings, G. Kane
Published in Electrochimica Acta
2016
Abstract
Abstract Extracted from the chloroplasts of green plants, Photosystem I (PSI) is a multi-subunit protein complex that can be deposited as a thin film onto electrodes and incorporated into biohybrid photovoltaic devices to convert sunlight into usable energy. Previously, our group characterized persistent photocurrents over nine months using {PSI} multilayer films in an aqueous solution of redox mediators. However, the loss of periphery {PSI} proteins upon exposure to mediator solutions is known to affect the photocatalytic performance of the overall film. The cross-linker 2-iminothiolane (2IT) is capable of connecting protein molecules with covalent bonds, and is herein used to stabilize {PSI} multilayer films on gold substrates against significant desorption/degradation. Results showed that the thickness retainment of the cross-linked {PSI} films was superior to that of non-cross-linked films. {PSI} films modified by 2IT maintained production of photocurrent with long-term exposure to aqueous solutions in contrast to non-cross-linked control films.