Constructing two-dimensional crossed molecular packing through branching chain engineering of amino-indenofluorene derivatives

Optimizing molecular packing to improve the charge transport properties of organic semiconductors is essential for solution processed organic electronics. Herein, we demonstrate a branching chain engineering strategy to optimize the molecular packing of the dialkylamino substituted indeno[1,2-b]fluorene-6,12-dione (IFD) derivatives. Through tailoring the relative lengths of the branched side-chains, we can precisely control the crystalline structures to be either one dimensional (1D) lamellar or two dimensional (2D) crossed molecular packing motifs. The performance of solution processed organic thin-film transistors (OTFTs) reveals that the 2D crossed packing motif facilitates much higher mobility than the 1D lamellar packing motif. Our results suggest that branching chain engineering could be a powerful strategy to design organic semiconductors with 2D molecular packing for high performance OTFTs.