Boosting electron extraction of inverted polymer solar cells using solution-processed nanocrystals as cathode interlayer

In this paper, a powerful photoconductive interfacial layer was achieved by employing Cd2SSe/ZnS quantum dots (CSSQDs) to modify the electron-transport layers (ETLs) in polymer solar cells (PSCs). With the optimal concentration of CSSQDs and superior film process condition, the power conversion efficiency (PCE) was increased from 4.12% to 6.49% for P3HT:ICBA based device, leading to a tremendous1.6-fold performance enhancement. Moreover, the interlayer of CSSQDs could effectively improve the light absorption, the electron transport and extraction, as well as the better interfacial contact between the ETLs and active layers, accordingly resulting in a higher short-circuit current density, fill factor, and a lower series resistance, respectively. Hence, the introduction of CSSQDs interfacial layer could obtain a remarkably increased performance for the inverted PSCs.