| 초록 |
Donor–acceptor-type polymers, PBDPBT-T, PBDPBT-TT, and PBDPBT-biT, were polymerized via Stille coupling reactions. In the unfavorable mode of DFT calculations, the distance (Dn, n= # of repeating units, n=1, 2) between BDP and BDP in the two main chains showed different results according to the π-spacers. Especially, TT caused larger D2 than T and biT. The UV-vis absorption spectra of PBDPBT-T and PBDPBT-biT films were red-shifted compared with the solution absorption, whereas that of a PBDPBT-TT film was blue-shifted. PBDPBT-T and PBDPBT-biT had high crystallinity and a strong tendency for face-on orientation. In contrast, PBDPBT-TT had low crystallinity and a tendency for edge-on orientation. Owing to differences of packing formation, the polymers had different JSC values. Polymer solar cell device was fabricated through a solution process, PBDPBT-biT exhibited PCE of 4.50 %, with JSC value of 8.6mA/cm2, VOC value of 0.88V, and an FF value of 59.4% at 1:1.5 ratio with PC70BM. |
