Effective panchromatic sensitization of electrochemical solar cells: strategy and organizational rules for spatial separation of complementary light harvesters on high-area photoelectrodes.

Dye-sensitized solar cells, especially those comprising molecular chromophores and inorganic titania, have shown promise as an alternative to silicon for photovoltaic light-to-electrical energy conversion. Co-sensitization (the use of two or more chromophores having complementary absorption spectra) has attracted attention as a method for harvesting photons over a broad spectral range. If implemented successfully, then cosensitization can substantially enhance photocurrent densities and light-to-electrical energy conversion efficiencies.

Dye-sensitized solar cells: sensitizer-dependent injection into ZnO nanotube electrodes.

Two porphyrin-based dyes with carboxylic acid tethers of differing acidity in both protonated and deprotonated forms were examined on ZnO nanotube electrodes. All of the dyes have similar surface coverage, but only the more acidic dye in the acid form injects electrons well; this dye is the only one that corrodes the ZnO. In control experiments on TiO(2) nanoparticle electrodes, both dyes load and inject in protonated and deprotonated forms.

Fast energy transfer within a self-assembled cyclic porphyrin tetramer.

The structure of a cyclic self-assembled tetramer of an asymmetric meso-ethynylpyridyl-functionalized Zn(II)-porphyrin was established by solution-phase X-ray scattering and diffraction; femtosecond transient absorption and anisotropy spectroscopies were used to (a) observe rapid energy transfer (3.8 ps(-1)) between porphyrin subunits and (b) establish that the transfer occurs between adjacent units.

Single nanoparticle based optical pH probe.

This paper describes the development of a nanoscale optical pH probe based upon the surface-enhanced Raman scattering (SERS) properties of silica-gold core-shell nanoparticles. In this approach, a thin layer of gold is deposited onto a core of silica to form a metallic nanoshell with surface plasmon modes in the red-to-near-infrared spectral region. The surface of the nanoshell is functionalized with a pH-sensitive SERS reporter molecule, 4-mercaptopyridine (4-MPy).

Re-examining the origins of spectral blinking in single-molecule and single-nanoparticle SERS.

Single metal nanoparticles and nanoaggregates are known to emit intense bursts of surface-enhanced Raman scattering (SERS) in an intermittent on and off fashion. The characteristic "blinking" timescales range from milliseconds to seconds. Here we report detailed temperature dependence (both heating and cooling) and light-intensity studies to further examine the origins of this intriguing phenomenon.

Cation-cation interactions between uranyl cations in a polar open-framework uranyl periodate.

Novel open-framework alkali metal uranyl periodates, having the formula A[(UO2)3(HIO6)(OH)(O)(H2O)].1.5H2O (A = Li, Na, K, Rb, Cs), have been prepared through mild hydrothermal synthesis.