Optical Characterization of Co-doped Single Crystal Organic Semiconductor with Emissive and Assist Dopants

Doping technologies for organic single crystals are still “greenfield” which have potential for bringing about big improvement to various kinds of organic semiconductor devices. In this research, we have successfully grown molecularly co-doped plate-like single crystal widegap organic semiconductor of PBD doped with an emissive dopant of DCM and assist dopant of C6 by simple solution process. The room temperature PL measurement was conducted, and it was confirmed that the energy transfer efficiency from PBD to C6 was drastically improved by assist dopant. We also investigated the polarization characteristics of fluorescent emission of the co-doped crystals and confirmed the orientation of polarization of C6 and DCM were rotated in 30 degrees. This result suggests that the in-plane dipole moment of the two differs by 30 degrees.