Additive-assisted “metal-wire-gap” process for N-type two-dimensional organic crystalline films

Abstract Two-dimensional (2D) organic crystalline films with thickness of several molecular layers have unique characteristics that ensure a brilliant prospect for electronic applications. However, achieving solution-prepared n-type 2D organic single-crystalline semiconductor films remains to be a challenge. In this study, a “metal-wire-gap” process with additive assistance is used to grow n-type 2D N,N′-1H,1H-perfluorobutyldicyanoperylene-carboxydi-imide (PDIF-CN 2 ) crystalline films. In particular, adding dioctylbenzothienobenzothiophene (C 8 -BTBT) as the additive into the growth solution facilitates the growth of 2D PDIF-CN 2 crystalline films with high morphological uniformity and single-crystalline features with hundreds of microns in size. The film formation mechanism discussed in this paper reveals that the C 8 -BTBT triggers crystallization by building a wetting heterogeneous interface for PDIF-CN 2 nucleation. Thus, additive-assisted crystallization technique has great potential for the solution-based preparation of n-type 2D molecular crystalline films.