| 초록 |
In particular, most high-performance PSCs based on a bulk heterojunction (BHJ) blend of polymer donor and fullerene derivatives, suffer from significant thermal and morphological instabilities, which are mainly due to massive phase separation driven by strong crystallization and fast diffusion kinetics of fullerenes. In this work, we demonstrated that the use of n-type polymers, instead of fullerene acceptors, can provide a solution to resolve these stability issues. As a model system, we compared the thermal and morphological stabilities of all-polymer solar cells (all-PSCs) and fullerene-based PSCs using the same polymer donor (PBDTTTPD), both of which had comparable peak power conversion efficiencies (PCEs) of 6-7%. We observed a remarkable contrast in their thermal stabilities, with the fullerene-PSCs becoming completely degraded after annealing for 5 h at 150 ˚C. |
