Light-induced water oxidation at silicon electrodes functionalized with a cobalt oxygen-evolving catalyst

Joep J. H. Pijpersa, Mark T. Winklerc, Yogesh Surendranatha, Tonio Buonassisic, and Daniel G. Nocera

Integrating a silicon solar cell with a recently developed cobalt-based water-splitting catalyst (Co-Pi) yields a robust, monolithic, photo-assisted anode for the solar fuels process of water splitting to O₂ at neutral pH.Deposition of the Co-Pi catalyst on the Indium Tin Oxide (ITO)-passivated p-side of a np-Si junction enables the majority of the voltage generated by the solar cell to be utilized for driving the water-splitting reaction.Operation under neutral pH conditions fosters enhanced stability of the anode as compared to operation under alkaline conditions (pH 14) for which long-term stability is much more problematic. This demonstration of a simple, robust construct for photo-assisted water splitting is an important step towards the development of inexpensive direct solar-to-fuel energy conversion technologies.

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Brian Walker, August Dorn, and Professor Moungi Bawendi--in collaboration with Professor Vladimir Bulovic in Electrical Engineering and Computer Science--have reported the fabrication of composite photodetectors consisting of J-aggregates conjugated to semiconductor nanowires in Nano Letters.

In this design, excitation energy transfers from J-aggregated dyes to the nanowires, enhancing the photocurrent at the J-aggregate absorption wavelength and creating a nanostructured solid-state photodetector whose self-assembly and aggregated antenna molecules are reminiscent of a photosynthetic light harvesting complex. The nanowire/J-aggregate self-assembly was demonstrated for J-aggregates at three different wavelengths (red, green, and blue), resulting in a color selectivity that may be useful for color imaging below the diffraction limit.

Ting and Nolan appointed to Chairs

L-R: Professors Alice Y. Ting and Elizabeth M. Nolan have been appointed respectively to the Ellen Swallow Richards Chair and the Pfizer Laubach Career Development ChairProfessor Ting has been a faculty member in the MIT Chemistry Department since 2002. Her work has been on the development of probes and reporters for live cell imaging. To simultaneously harness the power of genetics and the power of chemistry, Alice’s lab has frequently exploited enzymes that act on both protein and small-molecule substrates. Her lab has developed new technologies for imaging protein trafficking, protein-protein interactions, and enzymatic activity. Current research interests include imaging studies of synapse formation/development, and in vitro evolution of novel enzyme function.

Professor Nolan has been a faculty member since July 2009. Her current research interests include synergies between metal ion homeostasis, innate immunity and the host/pathogen interaction, and elucidating the roles of metalloproteins in other biological phenomena.