Recent progress of bulk heterojunction solar cells based on small-molecular donors

Organic bulk heterojunction (BHJ) solar cells based on small molecular donors have received great attentions recently, because small molecules possess the merits of high purity, well-defined molecular structures, definite molecular weights and high charge carrier mobility. The highest power conversion efficiency (PCE) of BHJ solar cells based on small molecular donors and fullerene derivative acceptors has reached 7.38%. In this review, we will briefly summarize the development of small molecular donor based BHJ solar cells in the past two years. These results suggest that small molecular donors are promising candidates for high efficiency BHJ solar cells.