Anthracene-based molecular emitters for non-doped deep-blue organic light emitting transistors

Abstract

A new anthracene-based twisted oligomer combining a rigid anthracene–xylene core with diphenylamine ends 4,4′-(anthracene-9,10-diyl)bis(2,5-dimethyl-N,N-diphenylaniline), DiPAXA, is herein presented as an efficient and deep blue emitter material. By exploiting DiPAXA as an emissive layer and 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) as a p-type semiconducting layer, we realize a blue emitting unipolar light emitting transistor (OLET) with a maximum external quantum efficiency (EQE) of 0.13%, a charge mobility up to 0.32 cm² V⁻¹ s⁻¹ and CIE color coordinates of (0.18, 0.21), i.e. closer to currently available standards (PAL, NTSC). Moreover, comparison with other anthracene-based blue emitters highlights the suitability of this family of twisted anthracene–xylene compounds for unipolar blue OLET applications as a result of the enhanced performances in terms of CIE coordinates and light emission output of newly synthesized DiPAXA.