P3HT:DiPBI bulk heterojunction solar cells: morphology and electronic structure probed by multiscale simulation and UV/vis spectroscopy.

Coarse grained molecular dynamics simulations are performed for a mixture of poly(3-hexylthiophene) (P3HT) and diperylene bisimide (DiPBI). The effect of different annealing and cooling protocols on the morphology is investigated and the resulting domain structures are analyzed. In particular, π-stacked clusters of DiPBI molecules are observed whose size decreases with increasing temperature.

Structure of P3HT crystals, thin films, and solutions by UV/Vis spectral analysis.

Optical absorption spectra of poly(3-hexylthiophene) (P3HT) are calculated in solution, spin-coated thin films, and the bulk crystal using a multiscale simulation approach. The structure of the amorphous thin film is obtained from coarse grained molecular dynamics (MD) simulations and subsequent back-mapping onto an atomistic force field representation. The absorption spectra are computed using TDDFT by statistically averaging over an ensemble of molecules taken from the MD simulations.

Innovative sensitizer DiPBI outperforms PCBM.

A new photorefractive (PR) material sensitized with a novel functional unit DiPBI is prepared based on the guest/host approach. This unique mixture exhibits strong absorption in the whole range of visible light. Moreover, the photorefractive performance as well as PR speed is improved by far compared to the widely used sensitizer PCBM.