Bulk heterojunction photovoltaics using broadly absorbing small molecules based on 2-styryl-5-phenylazo-pyrrole.

Three new soluble small molecules (B, B6, and A) with a low band gap based on 2-styryl-5-phenylazo-pyrrole were synthesized. Molecules B and B6 contained pyrrole and N-hexylpyrrole, respectively, as the central unit, which was connected to N,N-dimethylphenyl-4-azo on one side of the pyrrole molecule. Molecule A contained N-hexylpyrrole as the central unit, which was connected to anthracenyl-9-azo on one side of the pyrrole molecule.

Synthesis of a low-band-gap small molecule based on acenaphthoquinoxaline for efficient bulk heterojunction solar cells.

A novel small molecule (SM) with a low-band-gap based on acenaphthoquinoxaline was synthesized and characterized. It was soluble in polar solvents such as N,N-dimethylformamide and dimethylacetamide. SM showed broad absorption curves in both solution and thin films with a long-wavelength maximum at 642 nm.