Synthesis And Supramolecular Self-assembly Of Hydrogen Bonded Organic Semiconductors

The thin film morphology of organic semiconductors has a direct influence on the function, property and lifetime of their devices. Supramolecular self-assembly of organic semiconductors (SSOS) is an efficient method to control the thin film morphology. Therefore, SSOS is significant for the understanding and improvement of functionalities of corresponding devices. As one of the most wide-used supramolecular interactions, hydrogen-bond functionalized organic semiconductors are able to change the intermolecular arrangements and their microscale, nanoscale structures. And this has been regarded as an important way to organize organic semiconductors. In this paper, kinds of topological polymorph and micro-, nanostructures are constructed through the self-assembly of synthesized hydrogen-bond functionalized organic semiconductors with synergistic hydrogen-bonds and/orπ-πstacks. The chemical structures were characterized by NMR,GC-MS,MALDI-TOF MS. The self-assembled morphologies were characterized by SEM,STM,AFM etc. Then, the relationships between molecular structure and preparation condition and micro-, nano-scale structures are illustrated and discussed.In the first part, we designed and synthesized planar quinoacridone derivatives indolo[1,2,3-fg]indolo[3',2',1':8,1]quinolino[2,3-b]acridine-8,18-dione (DIQA) and precursor dimethyl 2,5-di(9H-carbazol-9-yl)terephthalate (DM-DCT) via Ullmann-Goldberg reaction and Friedel-Crafts reaction. DM-DCT shows apparent aggregation induced emission (AIE) with strong steric hindrance effect. It is discovered that tetragonous rods and plates in micro-, nano-scale were constructed from DIQA and structurally similar 5,12-di(2-(2-(2-methoxyethoxy)ethoxy)ethyl) quino[2,3-b]acridine-7,14-dione (DEQA) by solution process method. Mother-son microcrystal structures were obtained by the evaporation of DHQA solution in DMF. It is an efficient method to constructed micro-, nanostructure from planar quinoacridone derivatives, and selective for further devices.In the second part, three tetratopic oligomeric phenylene-ethynylenes end-capped with carboxylic groups were synthesized and the self-assembly behavior at liquid (octanoic acid)-solid (HOPG) interface were characterized by STM. The length effect is demonstrated here. We found that parallel network"returned"in mid-length TCBP's STM image while Kagoménetwork of the shortest TCB's. Longest TCTP sustains parallel network compared to reported shorter tetratopic acids. It demonstrated an effective routine controlling the polymorphic alternation of 2D self-assembly monolayers functionalized by supramolecular interactions. SAMs of mid-length TCBP shows the closest packing with the smallest unit cell size of ~4.25nm2 among three OPE-COOHs. It is also found that the longest TCTP's 2D self-assembly shows highest homogenous and largest-scale polymorphism than TCB's with smallest surface coverage, and amorphous SAMs of TCBP with most domains separated by smooth transition at the boundaries. Well-defined holes prove that Kagoménetwork of TCB is a good tiling design guiding for potential construction of organo-porous materials.In the third part, another series of tetratopic supramolecular monomers TCPP and TEPP with rigid tetraphenylporphrin scaffolds and coil side chains endcapped with carboxylic acids and ester groups were designed and synthesized. By feat of SEM results, nanowires, nanobelts and nanoballs were successfully prepared by solvents evaporation of solution drop cast on clean glass slide. With different supramolecular binding strength and noncovalent interaction, the J-aggregation and H-aggregation are revealed by the analysis of UV-vis spectra. In addition, the self-assembly mechanism were proposed on the basis of Sandwich stacking (H-aggregation) and dislocated parallel stacking (J-aggregation) controlled by the strength of supramolecular interactions.In the last part, to be more complex than planar molecules, SP1 and SP2, pair of unsymmetrical supramolecular monomers based on double 4-(4,6-diamino-1,3,5-triazin-2- ylamino) groups with double hydrogen-bonds and double (3-(6-methyl-4-oxo-1,4- dihydropyrimidin-2-yl)urea) groups with four hydrogen-bonds functionalized 9,9-diphenyl- fluorene derivatives, respectively, were designed and synthesized. It was discovered that SP1 and SP2 are all amorphous material with rather weak crystalline properties. It was also found that protonated 4-(4,6-diamino-1,3,5-triazin-2-ylamino) groups with HCl and steric diaryl- fluorenes are the key two facts to form hydrogel of SP1. In addition, the nanofiber of SP2 was also actualized by the evaporation of diluted CH2Cl2 solution with weak solubility assigned to the self-recognized tetra-hydrogen bonds of (3-(6-methyl-4-oxo-1,4-dihydro- pyrimidin-2-yl)urea) groups and steric diarylfluorenes.