As an alkoxycarbonyl-functionalizedpolythiophene derivative, PDCBT can form better nano-scaledmorphology which leads to a better device performance [181].It is well known that the number-average molecular weight(Mn) of a polymer shows a profound influence on macromolecular ordering and microstructure and additionally on optoelectronic and charge transport characteristics. At last, it is worthmentioning that the subject of the blend morphology dependence on the Mn of both the donor and the acceptor, thus thephotovoltaic performance of especially for all-polymer solar cells(APSCs).