The Morphology Engineering Of Nano-crystals From Dialkyl-fluorene Derivatives And Organic Semiconductor Devices

The carriers transfer behaviors in organic opto-electronic devices mainly attribute to theintermolecular exciton transitions. Therefore, the molecular arrangement and nano morphology ofthe film is another key element determining the device performance, instead of electronic structureenginering of the material. It is a throny challenge to achieve large-scale, high crystalline,homogeneous organic semiconductor thin film by morphology design and device fabrication, forhigh performance organic semiconductor device. Therefore, in the past few years, controlablesynthesis of organic semiconductor nano-materials has attracted great attention for tunnable thinfilm optoelectric properties. Last20years, the study of inorganic nanomaterials provides abundantsexperience for constructing organic nano-morphology. In contrast, organic nanomaterials take greatpriorities involving their widespread resources, band-gap tunablility, facile in preparation andsolution processing. Hence, due to their potential applications in optoelectronics, catalysis, energyconversion and information storage, etc, organic semiconductor becomes a new generation ofsemiconductor nanomaterial.As an important non-planar organic semiconductor material, diarylfluorene and its derivates hasreceived great attention in electroluminescent, information storage and other areas. Combining ourprevious work, herein, we systematic explores the self-assembly behavior of series organicsemiconductors of non-planar molecule such as the π-stacking diarylfluorene, pyrene substituteddiarylfluorene and aza-diarylfluorene. We reveal the relationship between morphology andmolecular structures, where a series of nano-morphology successfully synthesized through thesurfactant-assisted reprecipitation, including one-dimensional (nanowires, nanorods),two-dimensional (nanosheets, nanobelts) nanoarchitectures and a variety of novelhigh-dimensionality (polyhedra, flower-like). The optoelectronic properties are systematicinvestigatied as well as the preliminary exploration of laser behavior based on diarylfluorenenanosheets. We attempt to introduce the organic nanomerails above mentioned into the organic fieldeffect transistor (OFET) memory as charge storage elements, instead of traditional used inorganic ormetal nanoparticles. It exhibits significant hole-storage properties, where the current On/Off ratioswitching is1.18×104, as well as a memory window of38.0V.The study of the non-planar diarylfluorene self-assembly affords an effective approach ratherthan the morphology limitations of traditional planar conjugated molecules, and provides an important reference for the design strategy towards complex morphology from self-assembly oforganic semiconductors. Furthermore, the designable band-gape of organic semiconductivenanocrystals, as novel charge storage elements for transistor memory, provides a smart strategy forfabricating information storage devices with intelligence, meanwhile well-defined packing incrystals also allow us to reveal the operation mechanism of such memory device.