title: Photocurrent generation based on a light-driven proton pump in an artificial liquid membrane.
abstract: Biological light-driven proton pumps use light to move protons across a cell membrane, creating a proton gradient. Although photochromic compounds such as spiropyrans can reversibly convert between two structures with differing pKa values, spiropyrans have not been used to generate either a light-driven proton pump or an electrical current. Here, we report an artificial light-harvesting system based on a supported liquid membrane doped with a spiropyran. Irradiating the membrane with ultraviolet light induces a ring-opening reaction, converting spiropyran to merocyanine, whereas irradiation with visible light induces the reverse reaction. When the membrane is irradiated with ultraviolet and visible light on opposite sides, H(+) is taken up by merocyanine, carried through the polymeric membrane and released on the other side. We show that this system produces a light-induced proton flux, an electrical current with an efficiency of ∼0.12%, an open-circuit voltage of ∼210 mV and a membrane gradient of ∼3.6 ΔpH units. Alternating the sides illuminated with ultraviolet and visible light generates an alternating current.
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Geneva, Quai E. Ansermet 30, CH-1211 Geneva, Switzerland.
authors.forename: Xiaojiang
authors.initials: X
authors.lastname: Xie
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Geneva, Quai E. Ansermet 30, CH-1211 Geneva, Switzerland.
authors.forename: Gastón A
authors.initials: GA
authors.lastname: Crespo
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Geneva, Quai E. Ansermet 30, CH-1211 Geneva, Switzerland.
authors.forename: Günter
authors.initials: G
authors.lastname: Mistlberger
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Geneva, Quai E. Ansermet 30, CH-1211 Geneva, Switzerland.
authors.forename: Eric
authors.initials: E
authors.lastname: Bakker
mesh_terms: D040761:Biomimetic Materials / Q000737:chemistry* / Q000528:radiation effects; D008027:Light; D008567:Membranes, Artificial; D010783:Photometry / Q000295:instrumentation / Q000379:methods; D010788:Photosynthesis; D017494:Proton Pumps / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D008567:Membranes, Artificial; D017494:Proton Pumps