Synthesis and Characterization of Power Conversion Efficiency of D/A Structure Conjugated Polymer Based on Benzothiadiazole-Benzodithiophene

Benzothiadiazole-benzodithiophene을 기반으로 한 D/A구조의 공액 고분자 합성 및 광전변환 효율 특성 개선 연구

  • Seong, Ki-Ho (Department of Industrial Chemistry, Sangmyung University) ;
  • Yun, Dae-Hee (Department of Industrial Chemistry, Sangmyung University) ;
  • Woo, Je-Wan (Department of Industrial Chemistry, Sangmyung University)
  • Published : 2013.10.31

Abstract

In this study, the push-pull structure polymer for organic photo voHaics (OPVs) was synthesized and characterized. The poly{4,8-didodecyloxybenzo[1,2-b;3,4-b]dithiophene-alt-5,6-bis(octyloxy)-4,7-di(thiophen-2-yl)benzo[c][1,2,5]-thiadiazole} (PDBDT-TBTD) was synthesized by Stille coupling reaction using the benzothiadiazole (BTD) derivative as an electron acceptor and benzodithiophene (BDT) derivative as an electron donor. The structure of monomers and polymers was identified by $^1H-NMR$ and GC-MS. The optical, physical and electrochemical properties of the conjugated polymer were identified by GPC, TGA, UV-Vis and cyclic voltammetry. The number average molecular weight ($M_n$) and initial decomposition temperature (5% weight loss temperature, $T_d$) of PDBDT-TBTD were 6200 and $323^{\circ}C$, respectively. The absorption maxima on the film was about 599 nm and the optical band gap was about 1.70 eV. The structure of device was ITO/PEDOT : PSS/PDBDT-TBTD : $PC_{71}BM/BaF_2/Ba/Al$. PDBDT-TBTD and $PC_{71}BM$ were blended with the weight ratio of 1:2 which were then used as an optical active layer. The power conversion efficiency (PCE) of fabricated device was measured by solar simulator and the best PCE was 2.1%.

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