Effect of oxygen evolution catalysts on hematite nanorods for solar water oxidation.

Photochemical deposition of Co and Ni based oxygen evolution catalysts on hematite nanorods cathodically shifted the onset potential of photocurrent near to the flat band potential of hematite. A 9.5 fold enhancement in the photocurrent density at 0.86 V vs. RHE compared to the parent hematite photoanode was observed with the Ni-Bi/Fe(2)O(3) photoanode.

Polymer solar cells based on copolymers of dithieno[3,2-b:2',3'-d]silole and thienopyrroledione.

Novel low band gap copolymers based on dithienosilole and thienopyrroledione units were synthesized. Copolymer P1 with branched side chains on the TPD units demonstrated a PCE of 4.4% with a high V(oc) of 0.89 V for OPV applications while OTFT devices fabricated from a copolymer containing linear side chains (P2) performed better in OTFT device configurations.

Silicon nanowire grid polarizer for very deep ultraviolet fabricated from a shear-aligned diblock copolymer template.

A silicon (Si) nanowire grid ultraviolet (UV) transmission polarizer has been fabricated, and its performance was measured over the visible to deep UV range. A cylinder-forming polystyrene-b-poly(hexylmethacrylate) diblock copolymer was coated onto an amorphous Si layer supported on a fused silica substrate, then shear aligned and employed as a mask for reactive-ion etching, resulting in a Si grid of 33 nm period and multi-centimeter-squared area. Due to the high plasma frequency and UV reflectance of the deposited Si, this nanowire grid was able to polarize light down into the deep UV, including 193 nm.

Effect of dendrimer generation on electron self-exchange kinetics between metal tris(bipyridine) core dendrimers.

Here we report the first measurement of homogeneous electron transfer between oxidized and reduced metal tris(bipyridine) core dendrimers by NMR line-broadening; the results indicated that, as the generation of the dendrimer increased, the rate of self-exchange decreased.

Attenuating electron-transfer rates via dendrimer encapsulation: the case of metal tris(bipyridine) core dendrimers.

Heterogeneous electron-transfer rates in metal tris(bipyridine) core dendrimers were measured using Osteryoung square-wave voltammetry. Rates decreased with generation, and this decrease could be correlated with the molecular weight increase. These results indicate that the coordination number around the redox center did not play any special role in sterically encapsulating the redox center.

Synthetic approaches to an isostructural series of redox-active, metal tris(bipyridine) core dendrimers.

Several types of six-armed, metal tris(bipyridine) core dendrimers were synthesized. Bis-4,4'-alkoxy bipyridine dendrons were prepared and employed to make tris(bipyridine) dendrimers. Although the ruthenium-centered and iron-centered dendrimers displayed quasi-reversible cyclic voltammetry, the analogous cobalt-centered complex did not. The synthesis of 4,4'-disubstituted bipyridines containing -CH(2)OR groups proceeded in low yield. The reactions of the dicarbanion of 4,4'-dimethyl bipyridine prepared with LDA and mesylate, triflate, and bromide groups were found to result in no or poor yields of carbon-carbon bond formation. Use of KDA in place of LDA resulted in much higher yields of dendritic bipyridines.