| Summary: | 碩士 === 國立交通大學 === 應用化學系碩博士班 === 99 === In this study, poly(3-hexylthiophene) and poly[3-(6-bromohexyl)thiophene] with hydroxyl end group were synthesized. Both polymers were further polymerized with L-lactic acid via ring-opening polymerization to obtain the block polymer P3HT-b-PLLA and P3BHT-b-PLLA. In order to form the cylinder nano-structure for the block copolymers, the wt% of PLLA block was controlled between 20-25%. The synthesized block copolymers were characterized by DSC and UV spectroscopy to study their thermal and optical properities. The spin-casted thin film of P3BHT-b-PLLA was investigated by AFM to prove its cylinder morphology. After exposure with UV radiation, the P3BHT block was crosslinked and the PLLA block was etched with NaOH solution, resulting in a P3BHT porous film. This porous P3BHT was used to fabricate a bi-layers solar cell with the configuration of ITO/V2O5 /porous –P3BHT/PCBM/Al. This nano-ordered OPV device shows a Voc of 0.5 V, a Jsc of 4.62 mA/cm2, a FF of 16.86 %, and a PCE of 0.51 %.
In the second part of this study, we used P3HT-b-PLLA as an additive which was blended with P3HT and PCBM to modify the bulk heterojunction layer of an OPV device. The wt% of P3HT-b-PLLA was 0.5 wt%,1 wt%, and 1.5 wt%. The OPV device containing 0.5 wt% of P3HT-b-PLLA showed the highest PCE value of 4.49 %. If we compared its performance with the performance from the OPV device without P3HT-b-PLLA additive, its Jsc increases from 12.55 to 12.77 mA/cm2, FF increases from 57.41 to 58.63 %, and PCE increases from 4.18 to 4.49 %. The OPV device containing P3HT-b-PLLA also showed better thermal stability after long time thermal treatment.
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