| 초록 |
We compared the thermal and morphological stability of all-polymer solar cells (all-PSCs) and fullerene-based PSCs (fullerene-PSCs) having the same polymer donor (PBDTTTPD). We observed a remarkable contrast in thermal stability dependent upon the acceptor composition in the active layer, with the performance of the fullerene-PSCs completely deteriorating after annealing, whereas that of the all-PSCs remained stable even after annealing. Pronounced phase separation was observed in the active layer of the fullerene-PSCs. In stark contrast, almost no morphological changes in the all-PSCs were observed. Morphology of ternary blend active layers with different fullerene contents was also examined while annealing at 150 ºC. When included in the active layer as ＜30 wt% of the acceptor mixture, fullerene was well-dispersed in the amorphous portion of the donor/acceptor polymer blend under thermal stress, and led to thermally stable devices with a higher PCE (7.12%). |
