초록 |
Thermal degradation behavior of inverted polymer solar cells (PSCs) using various photoactive materials including fullerene- and non-fullerene acceptors are investigated at various temperature and time under nitrogen atmosphere. We select well-known inverted architecture of ITO/ZnO/active layer/MoO3/Ag. After thermal annealing, all the PSCs show more than 30% decrease in PCE within 1 h. We systematically investigate the reason for thermal degradation in terms of phase separation, energy level shift, and electrode degradation by using AFM, GIWAXS, ToF-SIMS, EIS, and etc. We find that phase separation and energy level shift of buffer layer do not occur. From the ToF-SIMS measurement, we observe that MoO3 diffuses into active layer with thermal stress, which acts as a charge trap site. |