Varied π-Conjugated Extension Directions in B←N Coordinated Benzodipyrrolidone (BDP) Polymer Semiconductors: Effects on n-Type Organic Field-Effect Transistors (OFETs)

In the current state of organic semiconductor development, n-type semiconductors are significantly less advanced than their p-type counterparts, particularly in the realm of high-electron-mobility materials, which are crucial for high-grade organic field-effect transistors (OFETs) in commercial electronics. Over the past few years, the incorporation of B←N coordination units has emerged as a promising approach to enhancing n-type properties. However, the exploration of polymers with π-conjugated extensions in different directions has been largely overlooked. This study introduces two novel B←N coordinated BDP-based polymers, P1 and P2, synthesized with distinct π-conjugated extension directions: along the backbone and perpendicular to it, respectively. P1, with its advantages in energy levels, planarity, crystallinity, and backbone transport, demonstrates an electron mobility of 1.81 cm 2 V –1 s –1, which is more than twice the performance of P2. This achievement sets a new benchmark for B←N coordinated n-type OFETs, marking one of the highest reported electron mobilities to date.