Solution Processable Se-annulated Swallow Tail Perylene Bisimide Exhibiting Room Temperature Columnar Phase and Efficient Ambipolar Charge Carrier Mobility

Abstract

This study presents a selenium-annulated perylene bisimide (PBI-Se^ST) stabilizing room temperature columnar hexagonal phase with exceptionally low clearing temperature. The synthesis of this Se-annulated PBI (PBI-Se^ST) was accomplished using the reductive Cadogan cyclization method, with the introduction of swallow tails to reduce the clearing temperature and improve solubility. In addition, the charge carrier mobility of the Se-bay annulated PBI is assessed by space charge limited current (SCLC) technique and juxtaposed with PBI as well as nitrogen and sulphur-bay-annulated PBIs. It is noteworthy that all these PBIs exhibited ambipolar charge carrier mobility, a characteristic that diverges from the prevailing literature where predominantly electron transport behavior was observed for PBIs. This distinguishes them as an exclusive category of solution-processable, self-assembling organic semiconductors.

Keywords: Ambipolar Charge carrier mobility; Columnar Liquid Crystal; Perylene bisimide; Se-annulation.