High-performance nonfullerene polymer solar cells with open-circuit voltage over 1V and energy loss as low as 0.54eV

摘要

AbstractIn this work, we developed high efficiency nonfullerene PSCs based on a wide bandgap polymer donor PBPD-Th with a structure ofmeta-alkoxyphenyl benzodithiophene-alt-thienyl benzodithiophene-4,8-dione and a low bandgap small molecule acceptor ITIC. The PBPD-Th shows a strong absorption in the short wavelength of 300–650nm with a bandgap of 1.91eV, which is complementary with that of ITIC (1.55eV). Moreover, PBPD-Th possesses a deep HOMO level of ?5.42eV, which is beneficial to obtain high open-circuit voltage (Voc) in PSCs. As a result, the optimal PSCs based on PBPD-Th: ITIC showed a power conversion efficiency (PCE) of 10.8% with aVocof up to 1.01V, a high short-circuit current density (Jsc) of 18.3mAcm?2and a fill factor (FF) of 59%, under the illumination of AM 1.5G, 100mWcm?2. Notably, the energy loss (Eloss) of the optimal PSCs is 0.54eV, which is smaller than the empirically low threshold of 0.6eV. The PCE of 10.8% is one of the highest values reported in the literatures for the PSCs withVocover 1.0V.Graphical abstractDispla