Functionalized Indazaboles: A New Class of Low-k Interfacial Layer for Multi-Polar Charge Transport in Organic Field Effect Transistors

Demonstration of high-performance field effect transistors (FETs) necessitates designing of ordered semiconductors as well as dielectric materials with a low degree of dipolar disorder. Majority of efforts for improving the performance of FETs has been directed toward modifying the semiconducting layer. Here, indazaboles, which are a class of relatively unexplored tetra-coordinated organoboranes, are utilized as an active interfacial layer in a field effect transistor structure. It is shown that with suitable functionalization of the indazabole core, it is possible to tune the dielectric constant ranging from 2.2 to 5.1. Such wide tunability of the dielectric constant makes these materials fundamentally interesting as a platform to controllably probe the effect of interfacial dipolar disorder on the field effect charge transport. These indazaboles, when introduced as a low k-modifying layer at the transport interface on conventional oxide dielectric result in significant enhancement of both electron and hole field effect mobility by up to six times. The results bring out the applicability of this new class of indazabole materials as dielectric material supporting multi-polar transport and provide insight for developing high performance field effect transistor through suitable interfacial chemical design.