| 초록 |
PBDTT-DbiT-DFQx (in) and (out) exhibited λmax of 538-547 nm in CB solution, 555~564 nm in thin film state and 1.86~1.90 eV in the Egopt. PBDTT-DbiT-DFQx (out) appeared as a shoulder peak in the solution state and the peak intensity improved in the film state. The shoulder peak of long wavelength is caused by the intermolecular transfer of π-π*, which is caused by aggregation of the alkyl side chain. The energy level of PBDTT-DbiT-DFQx (out) is lower than PBDTT-DbiT-DFQx (in). PBDTT-DbiT-DFQx (in) exhibited better Voc and FF compared to PBDTT-DbiT-DFQx (out) due to good π-π stacking and effective side chain orientation. However, PBDTT-DbiT-DFQx (in) was measured for poor Jsc because of the low solubility of CB and DCB. Under optimized states, the efficiency of PBDTT-DbiT-DFQx (in) achieved power conversion efficiency of 4.07%, Voc of 0.67 V, Jsc of 9.83 mA/cm2, FF of 0.62 |
