Synthesis And Application Of Transition Metal Ions Doped And Surfactant Modified Polyaniline In Dye-sensitized Solar Cells

The counter electrode is an important component of the dye-sensitized solar cell composition?DSSCs?,responsible for the transmission of external circuit electrons and catalytic regeneration of redox pairs.However,Pt is expensive and has limited reserves,limiting its large use in DSSCs.To this end,researchers have carried out a lot of research work to find other material that can replace Pt.Such as carbon materials,transition metal compounds,polymer conductive polymers,etc.have been used as counter electrode catalytic materials for DSSCs.Among the free-Pt counter electrode materials,the conductive polymer has the characteristics of simple synthesis process,abundant raw material source,strong plasticity and transparency,which are beneficial to reduce the production cost of DSSCs,and are especially suitable for industrial production of DSSCs.1)A macromolecule conductive polymer PANI was successfully synthesized by electrochemical and chemical methods.And the effects of transition metal ion doping and surfactant modification on the catalytic performance.The results showed that PANI synthesized by electrochemical method had a certain catalytic activity,the efficiency of DSSCs based on PANI was 3.87 %,the PANI electrode catalytic activity modified by Ni²⁺,Co²⁺ and Mn²⁺ ions was significantly improved,the efficiency of DSSCs was 4.70 %,4.57 % and 3.94 %,respectively.However,Cu²⁺ ion doping reduced the catalytic activity of PANI.The difference in catalytic activity was caused by a different coordination of metal ions with PANI.The catalytic activity of PANI synthesized by chemical method was lowly,the battery efficiency was only 1.94 %.Mn²⁺?Ni²⁺ and Co²⁺,doping can also enhance the catalytic activity of PANI,battery efficiency at 4.41% 2.36% and 2.10%.Cu²⁺ doping reduced the battery efficiency to 1.41%.In order to improve the conductivity of the electrode,MWCNT-PANI and Graphene-PANI composite electrode were prepared.The results showed that the catalytic activity of the elctrode composited with MWCNT or Graphene was obviously improved.The battery efficiency of the electrode based on Ni²⁺ and Co²⁺ doped MWCNT-PANI increased to 6.00 % and 5.75 % respectively.The battery efficiency of the electrode based on Mn²⁺ and Co²⁺ doped Graphene-PANI increased to 5.38 % and 4.65 % respectively.2)The effects of surfactants such as disodium ethylenediamine tetraacetate,ganoderma lucidum polysaccharides and sodium dodecyl sulfate on the catalytic performance of PANI synthesized by chemical method were investigated.The experimental results showed that the surface modification could obviously change the electrode morphology of PANI.The surface of PANI electrode modified by disodium EDTA was coral-like.The surface of PANI electrode modified by ganoderma lucidum polysaccharide was formed by the accumulation of micro-particles.The surface of PANI electrode modified by sodium dodecyl sulfate was typical of rod-like structure.Different electrode morphology resulted in different PANI catalytic activity.The battery efficiencies of PANI electrode modified by disodium EDTA,ganoderma lucidum polysaccharides and sodium dodecyl sulfate were 2.51 %,2.69 % and 4.25 %,respectively,which were higher than the efficiency?1.94%?of non-modified PANI as the electrode.In summary,Ni²⁺?Co²⁺ and Mn²⁺ doping can improve the catalytic activity of PANI electrode in different level.The catalytic performance of PANI can be further enhanced by MWCNT,Granphene composite or surfactant modification.The application of this free-Pt counter electrode material also contributes to reducing the cost of DSSCs and increasing their competitiveness in a variety of photovoltaic devices.