Hybrid crystals based on thiophene/phenylene co-oligomers

We have grown crystals in which two kinds of thiophene/phenylene co-oligomers (TPCOs) are hybridized. Biphenyl-capped thiophene (BP1T) and biphenyl-capped terthiophene (BP3T) were chosen from among the TPCOs. The hybrid crystals were grown in both the vapor phase and the liquid phase. These hybrid crystals showed the emission colors intermediate between the two components. Correspondingly maximum peak positions of the emissions from the hybrid crystals were located halfway between those from single-component crystals of BP1T and BP3T. We made hybrid thin films by co-deposition of the two TPCOs in vacuum. The thin films exhibited both emission colors and emission peak positions similar to those of the hybrid crystals. The X-ray diffraction measurements indicate that the crystallographic structure of the hybrid crystals resembles that of the BP1T crystal. Also we made field-effect transistors using the hybrid crystals and measured their hole mobilities. We briefly discuss the implications of the X-ray diffraction and electrical data.