摘要
Polymer-based solar cells (PSCs) have been promising candidates as renewable energy resources, having multiple advantages of flexible, low-cost and large-area processing for their mass production. Among them, much attention has been paid to fundamental bulk-heterojunction (BHJ) devices using a blend of regioregular poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) as the active layer. However, there are still significant limitations not only in the low power conversion efficiency (PCE), but also in the device stability. The morphological control of BHJ PSCs is one of the most important issues to improve the device performances. On the other hand, P3HT itself has received much attention in many fields, because it is the best class of balanced high-performance materials as a p-type semiconductor in terms of solubility, chemical stability, charge mobility, and commercial availability. The discovery of the quasi-living Grignard metathesis polymerization (or called catalysttransfer polycondensation) system has made it possible to synthesize a wide variety of chain-end-functional P3HT derivatives, their block copolymers and star-branched polymers. Since the competitive research areas including PSC applications have strongly demanded the accelerated developments of new materials and well-defined morphologies related to polythiophenes, the fundamental studies of P3HT have still been targeted by many research groups. In this review, the controlled synthesis of P3HT, the synthesis of P3HT-based block copolymers, their applications to PSCs, as well as the scope and potential of new thiophene-based materials are described.