Synthesis And Electrochromic Properties Of Thiophthene-EDOT Copolymers

Along with the increasing demand for smart windows,wearable electronic devices and optical storage devices,electrochromic devices?ECDs?with rapid reversibly optical conversion under ultralow electric stimulus have been rapidly developed.In contrast to other electrochromic materials,organic electrochromic polymers possess low processing cost and energy comsuption,good processing performance;especially in their physicochemical properties can be manipulated by fesible design of porcusor structure,thus electrochemic polymers are considered as the promising candidate for farbricating flexible and smart optoelectronic devices in current society.Recent researches demonstrate that fused compounds,e.g.,fused thiophenes,have widely used in organic photovoltaic cells?OPVs?,organic field-effect transistors?OFETs?,owing to their high planar conformation,extend?-conjugated ststem and enhancing carrier transport.Based on previous achievements on fused compouds,we herein propose to design and synthesize novel conducting polymer porcusors based on fused thiophenes and famous3,4-ethylenedioxythiophene?EDOT?and their derivatives,and polymerize them into conducting polymers.We systematically investigated the effects of different molecular conjugate lengths and molecular planarity on the physical and chemical,electrochemical and electrochromic properties,and revealed the relationship on the structure-performance of conducting polymer films.The electrochemic performance including optical contrast,coloring efficiency,response time,and stability were improved.Moreover,the electrochemic films possess multi-color conversion between red,green and blue.1.The electrochromic performance of PTT was improved by introducing EDOT unit in the main chain of PTT.The electrochemical copolymerization of TT and EDOT were achieved in ACN-Bu₄NPF₆system.The self-supporting films,i.e.P?EDOT-co-TT?,were prepared by optimized the polymerization potential,and those films present good conductivity and toughness.The structure and performance of copolymer films were explored by using CVs?FT-IR?¹H-NMR and other instruments.In comparsion to PTT,the electrochemic performance including optical contrast,coloring efficiency and response time of copolymers were improved obviously.2.The breakthrough of electrochromic properties of PTT conjugated polymers was achieved by effectively extending the planar conjugate length of the precursor.Two conducting polymer precursors were successful synthesized by employing EDOT as end-capped units and TT,DTT as core unit,and explored their electrochemical properties in CH₂Cl₂–Bu₄NPF₆system.The structure-performnace releationship were explored by using spectroscopic,morphological as well as the corresponding electrochemical characterizations.The resulting polymers PETTE and PEDTTE present good electrochemical activity and stability,and the electrochemical activity can maintain 69.73%and 43.2%after 10000 cycles.Notably,those conducting polymer films present excellent electrochemic performance including high optical conversion?59.61%?and coloring efficiency(288.37 cm² C^-1)as well as outstanding stability and coloring persistence.3.By changing the planar structure of the precursor,the polychromatic conversion and electrochromic properties of the PTT conjugated polymer were greatly improved.Two conducting polymer precursors with different planar structures,i.e.TT-EDOT-TT and TT-EDTT-TT,were successful synthesized by employing TT as end-capped units and EDOT or its derivative?EDTT?as core units,and careful characterize their electrochemical features in ACN–Bu₄NPF₆ system.The structure-performnace releationship of procurcers and polymers were explored by using theoretical calculation studies,spectroscopic,morphological as well as the corresponding electrochemical characterizations.Those films possess superior electrochemic performance including high optical conversion?70.8%?,coloring efficiency(331.3 cm² C^-1)and fast response time?0.72 s?.A systematic study of the effect of the spatial structure of polymer precursors on the properties of electrochromic polymers is vital for developing high-perfoemance electrochemic materials.