Polymer-fullerene miscibility: a metric for screening new materials for high-performance organic solar cells.

The improvement of the power conversion efficiency (PCE) of polymer bulk heterojunction (BHJ) solar cells has generally been achieved through synthetic design to control frontier molecular orbital energies and molecular ordering of the electron-donating polymer. An alternate approach to control the PCE of a BHJ is to tune the miscibility of the fullerene and a semiconducting polymer by varying the structure of the fullerene. The miscibility of a series of 1,4-fullerene adducts in the semiconducting polymer, poly(3-hexylselenophene), P3HS, was measured by dynamic secondary ion mass spectrometry using a model bilayer structure.

Effects of thermal annealing upon the nanomorphology of poly(3-hexylselenophene)-PCBM blends.

Grazing incidence X-ray diffraction (GI-XRD) is used to characterize the crystallographic dynamics of low molecular weight (LMW) and high molecular weight (HMW) poly(3-hexylselenophene) (P3HS) films and blend films of P3HS with [6-6-]-phenyl-C(61) -butyric acid methyl ester (PCBM) as a function of 'step-by-step' thermal annealing, from room temperature to 250 °C. The temperature-dependent GIXRD data show how the melting point of P3HS crystallites is decreased by the presence of PCBM. P3HS crystallite domain sizes dramatically increase upon annealing to the P3HS melting temperature.

A capping methodology for the synthesis of lower mu-oxo-phthalocyaninato silicon oligomers.

A mixed condensation of a substituted and unsubstituted silicon phthalocyanine monomer, in which the former serves as a "cap" to a growing oligomeric chain, provides unprecedented access to a mixed dimer, trimers, and a tetramer. An important element of product control can be achieved by changing the ratio of the precursor monomers.

Structural characterisation of a red phthalocyanine.

Metal 1,4,8,11,15,18,22,25-octakis(hexylsulfanyl)phthalocyanines exhibit a weak absorption band in the 450-600 nm region, leading to novel dyes that include the red lead metallated derivative that has been characterised by X-ray crystallography.