Since Shirakawa et al discovered that polyacetylene can reach extremely high conductivities, the polymer material has no longer been regarded as electrical insulators. Subsequently, the discovery of polyaniline, polypyrrole, poly(thiophene) expanded the type of conductive polymer. In addition, the conductive polymer has promising application in the fields such as electrode material, solar cell, and other applications, and some of them have achieved the commercialization. Among them, poly(thiophene)s has been widely concerned because of their good stability, easy preparation and good characteristics of photoelectrochemical performance after doping. Thus, in this review, several synthetic methods for poly(thiophene)s and their derivatives are reviewed, including chemical oxidation polymerization, electrochemical synthesis, and so on, especially the newly developed solid state polymerization and acid-assisted polymerization. Their synthesis mechanism, the advantages and disadvantages are also discussed.

Contents
1 Introduction
2 Synthetic methods
2.1 Chemical oxidation polymerization and electrochemical polymerization
2.2 Metal-catalysed polymerization
2.3 Photo-induced polymerization
2.4 Photo-electrochemically polymerization
2.5 Solid state polymerization
2.6 Acid-assisted polymerization
3 Conclusion and outlook