Precise Self-assembly Synthesis Of Organic Hierarchical Micro-/Nanostructures And Their Photonic Studies

Organic crystalline materials have attracted intensive attention in various optoelectronics deveices,including organic photodetectors.organic solar cells,organic field-effect transistors and organic solid-state lasers,due to the tailor-made molecular structure,amenability to low-cost and low-temperature processing,flexibility,tunable electronic/optical properties as well as minimized defects,high charge-carrier mobility and regular morphology.Owing to the diversity of crystallization characteristics and the difimcultv of manipulating non-covalent interactions among molecules,the precise self-assembly synthesis of organic crystal materials remains a huge challenge.The simple organic low-dimensional micro-nanostructure materials,which were obtained via the facile solution self-assembly method,physical vapor deposition or template method,have the increasing difficulty to meet the development of miniaturization and integration of optoelectronic devices.Therefore,the precise synthesis of organic hierarchical micro-nanostructure and the corresponding growth mechanisl have important significance in basic research and promising application for development of organic integrated optoelectronics.Through regulating the non-covalent interaction between molecules in the primary/hierarchical self-assemblv process,the precise synthesis of-organic hierarchical micro-nanostructure is realized.Moreovri:lic corresponding growth mechanisin has been systematically studied.The main contents are described follows:1.We utilize the synergy approach of the bottom-up and the top-down processes to fabrieate DMHP crystalline nanowires with diameters of 120± 10 nm through stepwise evolution.Specifically,the evolution processes vary from the self-assembled organic micro-rods with a quadrangular pyramid-like end-structure bounded with {111}s and{11-1 ｝s crystal planes to the "top-down" synthesized organic micro-rods With the flat cross-sectional {002}s plane.to the organic micro-tubes with a wall thickness of～115 nm.and finally to the organic nano wires.Notably.the anisotropic etching process caused by the protic solvent molecules(such as ethanol)is crucial for the evolution of the morphology throughout the whole top-down process.Based on the similar synergetic method,the binary organic 4.4’-((1 E,1’E)-(2,5-dimethoxy-1.4-phenylene)bis(ethene-2,1-diyl))dipyridine(DPEpe)and 1,4-diiodotetrafluorobenzene(F4DIB)single crystalline microrods and microtubes have been controllably f-abricated by tuning the solvent system through a facile solution-evaporation method.Due to the unique hollow structure for the good optical confinement at the interface,the microtubes realized an impressive lower optical loss of 0.0145 dB/μm than that of 0.0341 dB/μm for microrods.Therefore,our demonstration opens a new avenue for the controlled·fabrication of organic nanowires and microtubes for the development of the micromanipulation of optical propagation in the integrated circuits.2.Through the bottom-up process,2D halogen-bonded DPEpe-F4DIB cocrystals were fabricated that exhibit an asymmetric optical waveguide with the optical-loss coefficients of RBackward=0.0346 dB/μm and RForward=0.0894 dB/μm along the[010]crystal direction.which can be attributed to the unidirectional total internal reflection caused by the anisotropic molecular packing mode.Based on this crystal direction-oriented asyminetric photon transport,these asprepared 2D cocrystals have been demonstrated asainicroscale optical logic gate with multiple input/out channels,which will offer potential applications as the 2D optical component for the integrated organic photoriics.3.We demonstrate the one-dimensional organic core/shell micro-/nanostructures with component interchange.which originates from the DPEpe single-crystal microrods or the DPEpe-HCl single-crystal microrods after a reversible protonation or deprotonation process.Notably,the DPEpe/DPEpe-HCl core/shell microrods display vivid visualizations of tunable emission color via an efticient energy-transfer process during the stepwise formation of a shell layer.More significantly,these DPEpe/DPEpe-HCl and DPEpe-HCl/DPEpe core/shell microrods cooperatively demonstrate the multicolor optical waveguide properties continuously adjusted from green[CIE(0.326,0.570)],to yellow[CIE(0.516,0.465)],and to red[CIE(0.614,0.374)].Our investigation provides a new strategy to fabricate the organic core/shell micro-/nanostructures,which caneventually contribute to the advanced organic optoelectronics at the micro-/nanoscale.4.We present a precise synthesis of the Iongitudinal/horizontal epitaxial growth one-dimensional(ID)organic heterostructures including triblock and core/shell nanowires via a hierarchical self-assembly approach by regulating the noncovalent interactions:hydrogen bond(-15.66 kcal/mol),halogen bond(-4.90 kcal/mol),7r-7t interaction(-0.09 kcal/mol).In the facet-selective epitaxial growth strateg}’with the sequential crystallization,the lattice-matching and the surface-interface energy balance respectively facilitate the realization of triblock and core/shell heterostructures.Notably.the length ratio of red emissive region or the exposed degree of core part in the 1D organic heterostructures are quantitatively manipulated via adjusting the formation ratio of the hydrogen/halogen bonds.This approach provides a worthy enlightenment to precise constructing of organic heterostructure for the integrated organic optoelectronics,such as the nanoscale multiple inPut/out optical logic gate with absolute recognition ot NO/OFF state for high-fidelity signal.