Morphology-controlled self-assembly of an amphiphilic perylenetetracarboxylic diimide dimer-based semiconductor: from flower clusters to hollow spheres

A novel amphiphilic heptafluorobutyl-substituted perylenetetracarboxylic diimide dimer, 1-amino-3,5-[N-amino-N′-heptafluorobutyl-1,6,7,12-tetra(tert-butylphenoxy)-3,4:9,10-perylene diimide]-2,4,6-triazine, has been synthesized. The self-assembly properties of this dimer in mixed tetrahydrofuran/water (THF–H2O) solvents of different volume ratios were studied. Fine-tuning of the non-covalent interactions of the amphiphilic molecules in 75/25, 50/50 and 25/75 THF/H2O v/v mixtures led to the formation of micro-flower clusters, micro-bowknots and nano-hollow spheres, respectively. The conductivity of the micro-bowknots was about one order of magnitude higher than the conductivity of the micro-flower clusters and the nano-hollow spheres. On saturation with hydrazine vapour, the conductivity was dramatically increased by about three, four and five orders of magnitude for the micro-bowknots, micro-flower clusters and nano-hollow spheres, respectively, compared with the aggregates in air. These results suggest new opportunities for the design and preparation of high-performance sensing devices using a combination of molecular design and controlled intermolecular interactions in mixed solvents.