Chongqing University wide team Sun: large-scale in-situ deposition of polythiophenes film

Polythiophene conductive polymer is a material having conjugated long chain, having conductivity, environmental stability, excellent nonlinear optical properties, can be widely used in solar cells, thermoelectric devices, electrochromic devices and the like. However, since the polythiophene very low solubility in the solvent, which greatly limited the development and application of the film forming process in the device. Situ polymerization polythiophene film is an important way to the preparation of polythiophene films, but due to the high oxidation potential of thiophene monomer (> 1.65 V vs Ag / AgCl), the synthesis of polythiophene film difficult to increase. Currently situ synthesis thiophene film electrochemical synthesis method is used, so that by applying a sufficient voltage obtained by polymerizing polythiophene monomers film. Since the polymerization of thiophene peroxidation potential higher than the potential of the product often contains too polythiophene oxidized, reduced film quality. When the electrolyte is added to the number of Lewis acid such as boron trifluoride etherate can reduce the oxidation potential of some extent, to reduce the phenomenon of over-oxidation, enhance the film quality of the polythiophene. However, electrochemical synthesis is expensive and requires a conductive substrate, such that polythiophene can not be used in industrial production of non-conductive substrates such as glass and plastic surfaces in situ polymerization as a film, on the one hand limits the number which can be worn on the photovoltaic device and the flexible device the application, on the other hand can not meet the needs of large-scale preparation of industrial production. Based on this, under the guidance of Lee Wing-fang academician, Chongqing University researchers led by Sun wide flexible Renewable Energy Materials and Devices (La FREMD) team was compatible with the continuous preparation of a variety of substrates and large area phase polymerization (sequential solution polymerization, SSP) is applied to synthesis (FIG. 1) polythiophene. The method using V2O5 was dissolved in methanesulfonic acid as oxidant, at the surface of the substrate has deposited oxidizing agent solution and a monomer solution, and the resulting rapid polymerization polythiophene film. Experiments show that adding a small amount of methanesulfonic acid (0.2 vol%) to the monomer solution was effective to reduce the oxidation potential of the monomer, it is possible to successfully oxidative polymerization process in the SSP. Synthesis of thiophene units in the film is Cα-Cα connection, and there is no oxidation occurred. After washing with a solvent, and the oxidizing agent in the film is effectively removed most of methanesulfonic acid to give brick-red polythiophene film. Brick red polythiophene film is a completely neutral state, concentrated sulfuric acid – an electrochemical redox solvent cleaning and capable of reversibly doping and dedoping of polythiophene film, accompanied by a reversible blue -Red color change (see demo video), it shows the preparation of polythiophenes in the SSP electrochromic, color chemistry and other fields with great potential. Process

This results in a \”continuous phase prepared in situ polymerization of unsubstituted polythiophene and its chemical film / electrochromic applications \”(Unsubstituted polythiophene film Deposited via in-situ Sequential Solution polymerization for Chemo- / Electrochromism) was published in the journal Nature index\” on Macromolecules. \” Sun Wide Chongqing University researcher is corresponding author, doctoral student Chen Rui, and Dr Chen Shanshan Zhou Yongli is co-first author, undergraduate Chau Yin Wei and Wang Haiyan participated in the research project. The full text link: https: //pubs.acs.org/doi/10.1021/acs.macromol.0c00297