Anisotropic carrier transport in organic semiconductors studied by time-resolved optical second-harmonic generation

Anisotropic carrier transport characteristics in single crystalline grains of dip-coated TIPS pentacene films were studied using the time-resolved microscopic second harmonic generation (TRM-SHG). TRM-SHG imaging successfully visualized a difference in the transient carrier motion along various transport direction in ab-plane of TIPS pentacene single crystal. Mobility anisotropy observed in ab-plane was estimated as μ
_PARA
/μ
_PERP
= 3. We also applied this technique to visualize the anisotropic carrier transport in oriented organic polymer semiconductors.