Regular Organic Solar Cells with Efficiency over 10% and Promoted Stability by Ligand- and Thermal Annealing-Free Al-Doped ZnO Cathode Interlayer

Landmark power conversion efficiency (PCE) over 10% has been accomplished in the past year for single-junction organic solar cell (OSCs), suggesting a promising potential application of this technology. However, most of the high efficient OSCs are based on inverted configuration. Regular structure OSCs with both high efficiency and good stability are still rarely reported to date. In this work, by utilizing a new designed ligand-free and non-thermal-annealing-treated Al-doped ZnO cathode interlayer, high efficiency and greatly improved stability are simultaneously realized in regular OSCs. The highest PCE of 10.14% is accomplished for single-junction regular OSCs with active blend of poly [[2,6′-4,8-di(5-ethylhexylthienyl)benzo[1,2-b;3,3-b]dithiophene][3-fluoro-2[(2-ethylhexyl)carbonyl]thieno [3,4-b]thiophenediyl]] (PTB7-Th):[6,6]-phenyl C₇₁-butyric acid methyl ester (PC₇₁BM). Excellent device stability is confirmed as well, by keeping 90% of its initial PCE value after 135 d in N₂, and 80% of its initial PCE value after 15 d in ambient air, respectively. Furthermore, the applicability of the designed interlayer in regular OSCs is demonstrated by other active blend systems, including the nonfullerene material. This work highlights that high efficiency and good stability can be realized simultaneously in regular OSCs as well, and will provide referential strategy and methodology for this target.