Morphology Engineering Of Non-planar Organic Nanobricks And Application In Aqeous Processing Diode Memory Device

The bad film forming ability of small organic materials is a critical problem which limite their application in various devices. Currently, there are two methods for preparing thin films, the vaccum evaporation method and the solution processing method. However, to account for the low cost, simplified procedure for large-area processing, the vaccum evaporation method is not proper to fabricate small organic thin film. In the case of solution processing method, the few alternative material and determinate device structure seriously affect the development in low-cost small oeganic devices.An effective method to pave the way for small organic device is to alternate the organic active layer with small organic nano-film. The advantages are list as follows: first, the assembled micro/nanostructures of organic small molecules have properties beyond those of their bulk components and are more designable, second, various techniques to fabricate the nano-film from nanowire arrays and two-dimensional nanomaterials with have been reported in high-performance devices.In our base work, the non-planar molecules, especially the molecules with multiple large aromatic planes, can be promising candidates to form various polyhedral micro/nanocrystals by managing more space for spatial molecule stacking and tuning the cohesive energies of crystal facets compared with the planar molecules. If we add another π plane into the molecule, the molecular packment in one direction is likely to be constrained. Spirocyclic aromatic hydrocarbons(SAHs) with large π planes self assembled into a series of regular polyhedral crystals and could effectively suppress the fluorescence quenching caused by total π stacking and improve the luminous efficiency. The pyrene-sustituted SAHs(Py-SFDBAO) can assemble into ultrathin nanosheet and has been applicated in organic memory device. Pyrene is a typical polycyclic aromatic hydrocarbon with one π plane. The high stability of arylfluorene combinding with the high mobility and hole input ability of pyrene show great potentiality in materials for high- effecient blue light emission. The addition of pyrene unit in arylfluorenen molecule can possibly offer potential supramolecular interactions for molecule packing. In another word, the rational molecular design may realized the fabrication of ultrathin nanosheet.In this work, first we chose a similar non-planar molecule triptycene(TPC), which has sp3 C in the strcture, to furtherly confirm the conjecture of preparing polyhedral crystals with non-planar molecule. Computational and experimental work has been done and is well matched. The pyrene-substituted arylfluorene molecules are designed and prepared according to the work of Py-SFDBAO and structural analysis of lipid bilayer for assembly of 2D nanosheet. These nanostructures have been clearly investigated by field emission scanning electron microscope(FESEM), transmission electron microscope(TEM), selected area electron diffraction(SAED) and X-ray diffraction(XRD) patterns. The single crystal analysis conbinding with the morphology prediction are convincing proof of the controlled fabrication of 2D nanosheet. In the last chapter, the aqueous processed memory device with ultrathin nanosheet as the active layer is realized using the electrostatic spraying method and exhibit high reproducibility. The eco-friendly nanoink with abundant opto-electronic property will find its way in organic opto-electronics through constant optimization of device parameters.