CR-39 (PADC) Reflection and Transmission of Light in the Ultraviolet-Near-Infrared (UV-NIR) Range.

The spectral reflection (specular and diffuse) and transmission of Columbia Resin 39 (CR-39) were measured for incoherent light with wavelengths in the range of 200-2500 nm. These results will be of use for the optical characterization of CR-39, as well as in investigations of the chemical modifications of the polymer caused by ultraviolet (UV) exposure. A Varian Cary 5000 was used to perform spectroscopy on several different thicknesses of CR-39.

Photoinduced electron transfer from rail to rung within a self-assembled oligomeric porphyrin ladder.

Photoinduced electron transfer in a self-assembled supramolecular ladder structure comprising oligomeric porphyrin rails and ligated dipyridyltetrazine rungs was characterized by transient absorption spectroscopy and transient direct current photoconductivity to be mainly from an oligomer (rail) to the center of a terminal tetrazine (rung), with the remaining hole being delocalized on the oligomer and subsequent charge recombination in 0.19 ns.

Probing exciton localization/delocalization: transient dc photoconductivity studies of excited states of symmetrical porphyrin monomers, oligomers, and supramolecular assemblies.

Solution-phase transient dc photoconductivity (TDCP) measurements are used to address the question of exciton localization/delocalization in strongly coupled oligomeric porphyrins and in well-defined, higher-order assemblies of oligomers (ladder and prism assemblies). The approach used is determination of the excited-state excess polarizability volume, Delta alpha(V)--a quantity known to report on exciton delocalization. The measurements reveal for the oligomers that singlet excitons are substantially delocalized but that triplet excitons are much more localized.

Electron transfer in platinum(II) diimine-centered triads: mechanistic insights from photoinduced transient displacement current measurements.

The consequences of photoexcitation of a platinum diimine bisacetylide complex and its triads with phenothiazine species (McGarrah, J. E.; Eisenberg, R.

Dynamics of charge transport and recombination in ZnO nanorod array dye-sensitized solar cells.

Intensity modulated photovoltage and photocurrent spectroscopies reveal that photoanodes based on nanorod arrays exhibit dramatically faster electron transport while retaining similar electron lifetimes (recombination times) compared to standard photoanodes assembled from colloidal nanoparticles.

Nonadiabatic electron transfer at the nanoscale tin-oxide semiconductor/aqueous solution interface.

Photo-excitation of chromophoric metal complexes electrostatically adsorbed to tin-oxide semiconductor nanoparticles is often accompanied by injection of electrons from the complexes into the semiconductor conduction band. The mechanism of back electron transfer (semiconductor particle to adsorbed molecule) for a family of tris-bipyridyl ruthenium and osmium complexes has been examined by evaluating the kinetics of transfer to derivatives featuring alkyl substituents of varying length, methyl to pentyl. The substituents serve to change the electron transfer (ET) distance under conditions of weak chemical interaction with the semiconductor surface.

Dyads for photoinduced charge separation based on platinum diimine bis(acetylide) chromophores: synthesis, luminescence and transient absorption studies.

The platinum diimine bis(acetylide) chromophore was utilized to explore photoinduced intramolecular reductive quenching with phenothiazine donors in chromophore-donor dyad complexes. Compounds of the general formula Pt(X(2)-bpy)(C triple bond C-p-C(6)H(4)CH(2)(D))(2) (where D = phenothiazine (PTZ) or trifluromethylphenothiazine (TPZ) and X = (t)Bu or CO(2)Et) were synthesized from the corresponding Pt(X(2)-bpy)Cl(2) and aryl acetylene by a CuI-catalyzed coupling reaction. Solvent dependence was explored for the system with X = (t)Bu in MeCN, CH(2)Cl(2), EtOAc, and toluene.

Multiple emissions and brilliant white luminescence from gold(I) O,O'-di(alkyl)dithiophosphate dimers.

The Au(I) dimers Au(2)[S(2)P(OR)(2)](2) for R = Me, Et are found to exhibit a structure in which aurophilic interactions yield one-dimensional Au...