The Research Of The Oriented Constructure And Properties Of Conjugated Polymer In Confined Space

Being one of the typical soft materials, conjugated polymer owned the specialproperties such as soft, light weight, solution processing and its semiconductor property,these characters make it has wide application in various fields: organic field effecttransistor (OFETs), radio frequency identification, display, and statistics storage. However,due to the out-of-order and complicated microstructure of conjugated polymer system, itsphysical properties still cannot be compared with inorganic semiconductors. This paperuses solvent-assistant nanoimprinting method to produce confined geometry structure, andconcludes the orientation and crystal degree of the polymer chain in the limited space. Atlast, the orientation of molecular chain of conjugated polymer in confined space and itselectrical properties in organic filed effect transistor are well studied. Our research playsimportant role in promoting orientation of polymer chain, increasing the cattier mobility, aswell as improving the properties of organic device. We mainly start our research from thefollowing parts:(1) Conjugated polymer PDQT (poly [2,5-bis (2-octyldodecyl) pyrrolo [3,4-c]pyrrole-1,4(2H,5H)-dione-alt-2,2′:5′,2′′:5′′,2′′′-quaterthiophene) is chosen as ourresearch object, selecting chlorobenzene solvent which can prompt molecular chain closelypacked as PDQT’s solvent, using PDMS soft mold as our nanoimprint mold. In addition,solvent-assistant nanoimprinting method is adopted to engender two dimension confinedgrating structure of conjugated polymer PDQT under the condition of low temperature andlow pressure, thus making it crystallize in two dimension confined space.(2) Grazing Incidence Wide Angle X-rays Diffraction (GIWAXD) and Transmissionelectron microscope (TEM) are used to study the orientation of polymer chain and crystalline under the confined condition. We noticed that the molecular chain arrangedorderly on the confined direction, and the π-π direction is perpendicular to the line, formingedge-on orientation crystalline. Polarized ultraviolet absorption spectrum is utilized toexamine the orientation of molecular chain and crystal orientation degree.(3) OTETs device are made by oriented PDQT’s micronanostructure. The researchresults show that the oriented polymer chain can increase the carrier mobility effectively.We also find the orientation of polymer crystalline and molecular chain can be improved inconfined geometry constructrue at150℃or reduce the size of the confined space, then thecarrier mobility will be increased. Comparing with carrier mobility in film, the smallconfined size device increase by one order of magnitude at most.