Directed assembly of the thylakoid membrane on nanostructured TiO2 for a photo-electrochemical cell†
The thylakoid membrane mainly consists of photosystem I (PSI), photosystem II (PSII) and the cytochrome b6f embedded in a lipid bilayer. PSI and PSII have the ability to capture sunlight and create an electron–hole pair. The study aims at utilizing these properties by using the thylakoid membrane to construct a photo-electrochemical cell. A controlled aerosol technique, electrohydrodynamic atomization, allows a systematic study by the fabrication of different cell configurations based on the surfactant concentration without any linker, sacrificial electron donor and mediator. The maximum photocurrent density observed is 6.7 mA cm−2 under UV and visible light, and 12 μA cm−2 under visible light illumination. The electron transfer occurs from PSII to PSI via cytochrome b6f and the electron at PSII is regenerated by water oxidation, similar to the z-scheme of photosynthesis. This work shows that re-engineering the natural photosynthesis circuit by the novel technique of electrospray deposition can result in an environmentally friendly method of harvesting sunlight.