Organogels Based on PEDOT:PSS and Carbon-dots for Efficient Hole Transport in Organic Photovoltaics

摘要

Organic photovoltaic devices(OPVs)have received great attention in the past decades for next-generation renewable energy sources due to the low production cost and flexible structure.The structure of OPVs is commonly composed of anode,hole transport layer(HTL),photoactive layer,and cathode.In general,an electrically conducting polymer such as poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)(PEDOT:PSS)is used as the HTL to improve interfacial properties between the anode and photoactive layer.The PEDOT:PSS consists of hydrophobic and conductive PEDOT-chains doped with hygroscopic insulator PSS,resulting in poor electrical properties.It has been known that treatment of PEDOT:PSS with polar organic solvent or acid and annealing caused the conformational change and thus improved the electrical conductivity.However,controlling the orientation and shape of the PEDOT in PEDOT:PSS is still a challenge for improving the electrical percolation pathway.Recently,the electrical conductivity of PEDOT:PSS has been enhanced by inducing the gelation of PEDOT through self-assembly with graphene oxide(GO)and/or graphene quantum dots(GQDs).Although the gelation of PEDOT:PSS improved its mechanical,thermal,and electrical properties,its morphological changes and gelation mechanism in thin films have not been well understood.