| 초록 |
Organic solar cells can be very attractive energy sources because of low cost, light weight, large area, and mechanical flexibility. The efficiency of photoinduced charge separation is most crucial in determining the overall device efficiency in organic solar cells. To achieve high power conversion efficiency, long exciton diffusion length is required for donor-acceptor heterojunction to affect efficient charge separation. The diffusion length of singlet state excitons in photovoltaic materials is, however, usually several nm. On the other hand, the lifetime of triplet state excitons is much longer than singlet state excitons because of spin-forbidden direct back electron transfer by intersystem crossing. In order to use triplet state exciton to organic solar cell, the phosphorescent materials were doped to conjugated polymer. |
