| 학회 |
한국공업화학회 |
| 학술대회 |
2015년 봄 (04/29 ~ 05/01, BEXCO (부산)) |
| 권호 |
19권 1호 |
| 발표분야 |
고분자_포스터 |
| 제목 |
Study for Bimolecular Crystals of Amorphous Polymer:PCBM Intercalated Structure for Improving PPV-based Organic Photovoltaics |
| 초록 |
The exciton dissociation, recombination, and charge transport of bulk heterojunction (BHJ) organic photovoltaic cells (OPVs) is strongly influenced by the nano-morphology of the blend such as the grain size and the molecular packing. Although it is well-known that amorphous poly(p-phenylenevinylene)(PPV)-based polymers have a fundamental limit to achieve high efficiency because of low carrier mobility leading to increased recombination and unbalanced charge extraction, herein, we demonstrate that the issues can be overcome by forming bimolecular cystals of amorphous PPV-based polymer: phenyl-C61-butyric acid methyl ester (PCBM) intercalated structure. We used amorphous poly(2,5-dioctyloxy-p-phenylene vinylene-alt-2’,5’-thienylene vinylene) (PPVTV) having a simple chemical structure. Then, a reasonably high power conversion efficiency (PCE ~3.5%) was obtained, although it has intrinsically an amorphous structure and a relatively large band gap (2.0 eV). We also demonstrate a correlation between a well-ordered bimolecular crystal of PPVTV:PCBM and an improved hole mobility of a PPVTV:PCBM film compared to a pristine PPVTV film by using 2D Grazing Incidence X-Ray Diffraction (GIXD) and space-charge-limited current (SCLC) measurements, respectively. Furthermore, we show that the bimolecular crystal structure in high performance OPVs is related to an optimum molecular packing, which is influenced by the PPVTV:PCBM blending ratio, side chain length and molecular weight of the PPVTV polymer. Improved charge transport in PPVTV:PCBM bimolecular crystals leads to a fast sweep out of charges and thus suppression of non-geminate recombination under operating conditions. |
| 저자 |
임경근1, 박준모2, Hannah Mangold3, Frédéric Laquai3, 최태림2, 이태우1
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| 소속 |
1POSTECH, 2SNU, 3Max Planck Research Group |
| 키워드 |
Bimolecular Crystals; Organic Photovoltaic; PPV; GIXD
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| E-Mail |
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