Highly Luminescent 2D‐Type Slab Crystals Based on a Molecular Charge‐Transfer Complex as Promising Organic Light‐Emitting Transistor Materials

• DOI: 10.1002/adma.201701346
• Publication Date: 2017-07-26T13:07:23Z
• Authors: Sang Kyu Park; Jin Hong Kim; Tatsuhiko Ohto; Ryo Yamada; Andrew O. F. Jones; Dong Ryeol Whang; Illhun Cho; Sangyoon Oh; Seung Hwa Hong; Ji Eon Kwon; Jong H. Kim; Yoann Olivier; Roland Fischer; Roland Resel; Johannes Gierschner; Hirokazu Tada; Soo Young Park
• Keywords: 02 engineering and technology; 0210 nano-technology

A new 2:1 donor (D):acceptor (A) mixed‐stacked charge‐transfer (CT) cocrystal comprising isometrically structured dicyanodistyrylbenzene‐based D and A molecules is designed and synthesized. Uniform 2D‐type morphology is manifested by the exquisite interplay of intermolecular interactions. In addition to its appealing structural features, unique optoelectronic properties are unveiled. Exceptionally high photoluminescence quantum yield (ΦF ≈ 60%) is realized by non‐negligible oscillator strength of the S1 transition, and rigidified 2D‐type structure. Moreover, this luminescent 2D‐type CT crystal exhibits balanced ambipolar transport (µh and µe of ≈10−4 cm2 V−1 s−1). As a consequence of such unique optoelectronic characteristics, the first CT electroluminescence is demonstrated in a single active‐layered organic light‐emitting transistor (OLET) device. The external quantum efficiency of this OLET is as high as 1.5% to suggest a promising potential of luminescent mixed‐stacked CT cocrystals in OLET applications.