Synthetic Photoelectrochemical Complexes for Solar Energy Conversion That Self-Regenerate

Naturally occurring photosynthetic systems in plants are supported by elaborate pathways of self-repair that limit the impact of photo-damage and degradation. Despite advantages in stability and fault tolerance, synthetic photoelectrochemical systems have to date been invariably static. Herein, we demonstrate a complex consisting of two recombinant proteins, phospholipid and a carbon nanotube that reversibly assembles into a particular configuration, forming an array of 4 nm lipid bilayers housing light-converting proteins orientated perpendicular such that the hole conducting site is in close proximity to the nanotube conductor. The complex can reversibly self-assemble into this useful configuration, and disassemble to free components upon the addition of sodium cholate, over an indefinite number of cycles. The assembly is thermodynamically meta-stable and can only transition reversibly between free components and assembled state if the rate of surfactant removal exceeds about 10-5 sec-1. In the assembled state only, the complexes exhibit high photoelectrochemical activity using a dual Fe(CN)63-/ubiquinone mediator with external efficiencies near 40% that are repeatedly recoverable even after continuous cycles of disassembly and regeneration. By mimicking natural repair processes, such systems may lead to more robust and facile solar conversion systems.