Nguyen NN, Lee HC, Yoo MS, Lee E, Lee H, Lee SB, Cho K. Charge-Transfer-Controlled Growth of Organic Semiconductor Crystals on Graphene.
ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020;
7:1902315. [PMID:
32195079 PMCID:
PMC7080519 DOI:
10.1002/advs.201902315]
[Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 11/09/2019] [Indexed: 06/10/2023]
Abstract
Controlling the growth behavior of organic semiconductors (OSCs) is essential because it determines their optoelectronic properties. In order to accomplish this, graphene templates with electronic-state tunability are used to affect the growth of OSCs by controlling the van der Waals interaction between OSC ad-molecules and graphene. However, in many graphene-molecule systems, the charge transfer between an ad-molecule and a graphene template causes another important interaction. This charge-transfer-induced interaction is never considered in the growth scheme of OSCs. Here, the effects of charge transfer on the formation of graphene-OSC heterostructures are investigated, using fullerene (C60) as a model compound. By in situ electrical doping of a graphene template to suppress the charge transfer between C60 ad-molecules and graphene, the layer-by-layer growth of a C60 film on graphene can be achieved. Under this condition, the graphene-C60 interface is free of Fermi-level pinning; thus, barristors fabricated on the graphene-C60 interface show a nearly ideal Schottky-Mott limit with efficient modulation of the charge-injection barrier. Moreover, the optimized C60 film exhibits a high field-effect electron mobility of 2.5 cm2 V-1 s-1. These results provide an efficient route to engineering highly efficient optoelectronic graphene-OSC hybrid material applications.
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