Energy Conversion in Natural and Artificial Photosynthesis

McConnell, Iain; Li, Gonghu; Brudvig, Gary W.

doi:10.1016/j.chembiol.2010.05.005

Cited by 382 publications

(324 citation statements)

References 132 publications

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“…Light harvesting in natural photosynthesis is accomplished by a hierarchical assembly of accessory pigments that funnel their excitation energy to chlorophyll molecules (3). The core of chlorophyll-a is a substituted chlorin (4), a porphyrin ring with a reduced exo double bond (5).…”

mentioning

confidence: 99%

Metal-free organic sensitizers for use in water-splitting dye-sensitized photoelectrochemical cells

Swierk¹,

Méndez-Hernández

McCool³

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

135

106

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Solar fuel generation requires the efficient capture and conversion of visible light. In both natural and artificial systems, molecular sensitizers can be tuned to capture, convert, and transfer visible light energy. We demonstrate that a series of metal-free porphyrins can drive photoelectrochemical water splitting under broadband and red light (λ > 590 nm) illumination in a dye-sensitized TiO2 solar cell. We report the synthesis, spectral, and electrochemical properties of the sensitizers. Despite slow recombination of photoinjected electrons with oxidized porphyrins, photocurrents are low because of low injection yields and slow electron self-exchange between oxidized porphyrins. The free-base porphyrins are stable under conditions of water photoelectrolysis and in some cases photovoltages in excess of 1 V are observed.

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mentioning

confidence: 99%

Metal-free organic sensitizers for use in water-splitting dye-sensitized photoelectrochemical cells

Swierk¹,

Méndez-Hernández

McCool³

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

135

106

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“…The electron transfer (ET) 2 reactions in photosynthetic reaction center (RC) proteins are of prime interest because their high yield and effective stabilization of charge-separated states usually are unparalleled in artificial systems. Understanding all aspects of these reactions may inspire technical devices for sunlight-powered sustainable production of fuels, e.g.…”

mentioning

confidence: 99%

Carboxylate Shifts Steer Interquinone Electron Transfer in Photosynthesis

Chernev

Zaharieva

Dau

et al. 2011

Journal of Biological Chemistry

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Understanding the mechanisms of electron transfer (ET) in photosynthetic reaction centers (RCs) may inspire novel catalysts for sunlight-driven fuel production. The electron exit pathway of type II RCs comprises two quinone molecules working in series and in between a non-heme iron atom with a carboxyl ligand (bicarbonate in photosystem II (PSII), glutamate in bacterial RCs). For decades, the functional role of the iron has remained enigmatic. We tracked the iron site using microsecond-resolution x-ray absorption spectroscopy after laser-flash excitation of PSII. After formation of the reduced primary quinone, Q A ؊ , the x-ray spectral changes revealed a transition (t1 ⁄ 2 ≈ 150 s) from a bidentate to a monodentate coordination of the bicarbonate at the Fe(II) (carboxylate shift), which reverted concomitantly with the slower ET to the secondary quinone Q B . A redox change of the iron during the ET was excluded. Density-functional theory calculations corroborated the carboxylate shift both in PSII and bacterial RCs and disclosed underlying changes in electronic configuration. We propose that the iron-carboxyl complex facilitates the first interquinone ET by optimizing charge distribution and hydrogen bonding within the Q A FeQ B triad for high yield Q B reduction. Formation of a specific priming intermediate by nuclear rearrangements, setting the stage for subsequent ET, may be a common motif in reactions of biological redox cofactors.

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“…In addition, synthesis of a photonic macroporous morphology has been described previously. 5 The macroporous materials described here exhibit the inverse opal structure and the position of optical stop bands are given by Eqn. 1 which allows predictable modification of the stop band position. max is the stop band maximum, n is the relative refractive indices of the void and wall materials, d hkl is the void lattice plane spacing,  is the volume of the wall or 'fill factor', and m is the Bragg plane order.…”

Section: Synthesis and Characterisationmentioning

confidence: 99%

“…[1][2][3] Many challenges remain, requiring the discovery of new materials and structures for light capture, charge separation and catalysis, and the integration of these phenomena into a functioning device. 4,5 For light capture, the morphology of the absorbing material or structure supporting the light-active species is important to maximize absorption. 6 3-dimensional macroporous photonic structures exhibit potentially useful phenomena for increasing the efficiency of solar energy conversion.…”

Section: Introductionmentioning

confidence: 99%