Growth of Long Triisopropylsilylethynyl Pentacene (TIPS-PEN) Nanofibrils in a Polymer Thin Film During Spin-Coating

This study demonstrates the growth of long triisopropylsilyethynyl pentacene (TIPS-PEN) nanofibrils in a thin film of a crystalline polymer, poly(epsilon-caprolactone) (PCL). During spin-coating, TIPS-PEN molecules are locally extracted around the PCL grain boundaries and they crystallize into [010] direction forming long nanofibrils. Molecular weight of PCL and weight fraction (alpha) of TIPS-PEN in PCL matrix are key factors to the growth of nanofibrils. Long high-quality TIPS-PEN nanofibrils are obtained with high-molecular-weight PCL and at the alpha values in the range of 0.03-0.1. The long nanofibrils are used as an active layer in a field-effect organic transistor.