What decides the mobility of small molecule-based organic semiconductors in organic thin film transistors ?

The design of organic molecules-based devices with higher charge carrier mobility requires an in-depth understanding of elementary processes relevant to transport of charge carriers in organic thin films. Carrier mobility is large if there is a significant overlap between the molecular orbitals. Here, the exact role of chemical structure and arrangement of molecules in their crystal structure on the performance of metal-free (H2Pc)- and metal phthalocyanines (ZnPc, CuPc and F16CuPc)-based organic thin film transistors (OEFTs) has been observed by a combined experimental and theoretical study.