How To Obtain High-Quality and High-Stability Interfacial Organic Layer: Insights from the PTCDA Self-Assembly

Abstract

Organic/inorganic interfaces play dominant roles in the formation of organic thin films and the performance of organic electronic devices. Preparing a high-quality and high-stability interfacial organic layer on the inorganic substrate is currently challenging, and understanding the self-assembly mechanism of the interfacial layer (IL) in depth at a molecular level is thus essential. In this work, by studying the self-assembly of perylene-3,4,9,10-tetracarboxylic dianhydride IL on graphene, we unveil that intermolecular H-bonds can considerably widen the nucleation area, heighten the stability–metastability critical temperature, promote the nucleation speed, and guide the nucleation direction. We further demonstrate that such positive effects on the IL self-assembly are of generality. Moreover, it is found that IL can transform into a well-ordered crystal from an amorphous state through suitable thermal treatment or molecule coverage control. Our work highlights that fabricating H-bond networks is desirable for the synthesis of robust and high-quality IL and points out feasible routes to improve the quality of poor IL.