Acetylene bridged alkoxyphenanthrene and triarylamine-based triads for low threshold voltage with high mobility OFETs

摘要

A series of new triarylamine appended alkoxyphenanthrenes connected through acetylene bridges were synthesized for high-performance p-channel OFETs. These semiconductors exhibited high-lying HOMO energy levels up to 5.16 eV, enabling hole-transport properties and reducing the energy barrier for charge injection. Phenanthrene-based organic field-effect transistors were fabricated in the bottomgated top-contact architecture, and the device performances were dramatically improved with electronrich substituents. The OFET devices exhibited a maximum charge carrier mobility of up to 3.5 cm2 V1 s1 with a high ON/OFF current ratio of 108 and the lowest threshold voltage of 3 V. Altering the donor arms in D0-p-D-p-D0 based phenanthrenes highly influences the molecular packing, thin film morphology, and charge transport of the active layer, which results in high OFET performance. The efficient p-p interactions and the crystalline nature of the films are well proved by GIXRD and SEM analyses.