Tuning Biradical Character to Enable High and Balanced Ambipolar Charge Transport in a Quinoidal π-System

Herein, two bis(dicyanomethylene)-substituted quinoidal molecules QBDT and QTBDT-3H were designed and synthesized to explore the open-shell effect on tuning the charge transport behavior of organic pi-functional materials. The biradical character of QTBDT-3H was confirmed by DFT calculation, variable-temperature NMR, electron spin resonance (ESR), and superconducting quantum-interfering device (SQUID). The open-shell character enables QTBDT-3H an ambipolar characteristic under ambient conditions with highly balanced electron and hole mobilities of 0.32 and 0.16 cm(2) V-1 s(-1), respectively.