Recent development and understanding of polymer–nanocrystal hybrid solar cells
Solar cells are being rapidly developed nowadays due to the limited resources of fossil fuels and the worldwide growing energy demand. Polymer–nanocrystal solar cells (HSCs) are promising candidates thanks to the lightweight and mechanically flexible properties of polymers and the adjustable absorption, high carrier mobility, and superior structural stability properties of nanocrystals. However, compared with polymer–fullerene/organic molecule solar cells (PSCs), the development of HSCs is relatively sluggish, which is due to the complex characteristics of the polymer–nanocrystal system and the incomplete understanding of the operation mechanism. This review gives a brief introduction to device structure and operation mechanism of bulk heterojunction HSCs, and the differences between HSCs and PSCs will be emphasized. Recent work that has been done to improve the device performance or clarify the operation mechanism is summarized and discussed in detail. Both organic-solution-processed and aqueous-solution-processed HSCs will be discussed. Finally, the challenges and perspectives of HSCs will be presented.