Synthesis,Characterization And Properties Of Poly (Diphenylamine-4-Sulfonic Acid) Doped PEDOT

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid)(PEDOT:PSS)has been widely used as the hole transport layer(HTL).PEDOT:PSS is spin-coated on the transparent anode such as indium tin oxide(ITO)to smooth its surface,reduce the energy gap between ITO and light absorption layer and improve the efficiency of hole transport.PEDOT:PSS aqueous solution has the advantages of good dispersion stability,good film formation,easy processing,high light transmittance,chemical/optical stability,etc.However,the shortcomings of PEDOT:PSS such as high acidity,low work function(WF)and conductivity limit the improvement of solar cell performance and the expansion of its application scope.Considering the intrinsic insulated,high acidity PSS with large particle size in conductive PEDOT:PSS,a water-soluble polyaniline sulfonic acid(PDAS)was designed and synthesized.High conductivity and neutral conductive polymer PDAS was obtained by optimizing reaction time and oxidant dosage(0.08 S/cm and pH=7.7).Self-doped and high-radical content of PDAS exhibits superior electrochemical properties with WF of-5.3 eV.PDAS was applied to organic solar cells(OSCs)as the hole transport layer.The characteristics of the suitable WF,good conductivity and film uniformity of PDAS made the PCE of the devices based on PDAS(HTL)closed to that of PEDOT:PSS.PDAS was used to dope and disperse PANI as a conductive dispersant,and the water-soluble PANI with good electrochemical properties and stable dispersion was prepared.In order to improve the structure and conductivity uniformity of PEDOT derivatives,conductive dispersant PDAS was applied to efficiently dope PEDOT to obtain a novel waterdispersed conductive polymer PEDOT:PDAS.The existence of free radicals makes PDAS conductive,and conductive dispersant PDAS can improve the conductivity of PEDOT composite.Compared with the traditional PEDOT:PSS,PEDOT:PDAS show much higher conductivity(0.135 S/cm),deeper WF(-5.38 eV),lower acidity(around pH=7),outstanding film formation and prospective structural homogeneity.The WF of PEDOT:PDASs can be adjusted by changing the amount of dispersant.OSCs using PEDOT:PDAS as HTL showed comparable performance with the PEDOT:PSS control devices.More interestingly,PEDOT:PDAS powder can be re-dispersed for several times due to the weak aggregation between PEDOT backbone and PDAS.Our studies provide a practically feasible approach for the efficient storage and transportation of PEDOT ink for future industrial application such as antistatic coating.In a word,a novel self-doping polymer PDAS with high conductive,neutral and branched structure was synthesized.PDAS not only can be used as a hole transport layer material,but also as a dopant to disperse other conductive polymers such as PANI and PEDOT to obtain conductive material with excellent properties.