Influence of CN Substitution on DPP-furan-based Small-molecule Acceptors for Polymer Solar Cells

국문 초록 (Abstract)

본 연구에서는, 스즈키 짝지음 반응을 이용하여 p- 및 o-DPP-F-PhCN의 두 단분자를 합성하여 고분자 태양전지의 비풀러렌계 어셉터로 사용하였다. 치환기의 위치 및 퓨란 효과에 따른 단분자의 물리적 특성 변화를 살펴보았다. 퓨란 그룹의 도입으로 단분자는 더 높은 상전이 온도와 HOMO 및 LUMO 준위를 나타내었다. o-치환 역시 분자의 에너지 준위를 높게 함으로써, o-DPP-F-PhCN의 에너지 준위가 가장 높게 나타났다. 상대적으로 강하고 장파장 이동된 UV-vis 흡수는 o-DPP-F-PhCN의 강한 분자 응집을 나타낸다. P3HT와 DPP-F-PhCN들을 각각 고분자 도너와 비풀러렌계 어셉터로 사용한 고분자 태양전지를 제작하였고, 두 DPP-F-PhCN이 유사한 효율을 나타내었다. o-DPP-F-PhCN의 강한 응집 거동은 외부양자효율에 유리하였으나, 향상된 오비탈 상호작용에 따른 안정화된 LUMO준위로 인해 상대적으로 낮은 개방전압 값을 나타내었다.

다국어 초록 (Multilingual Abstract)

In this study, two small-molecules, p- and o-DPP-F-PhCN, were synthesized via a Suzuki coupling reaction and used as nonfullerene acceptors (NFAs) for poly(3-hexylthiophene) (P3HT)-based polymer solar cells (PSCs). The physical properties of the molecules were examined in terms of the substituent position and the effect of the furan moiety. The introduction of a furan moiety resulted in higher phase-transition temperatures and higher-lying molecular orbital energy levels of the molecules. Substitution at the ortho position also elevated the energy levels of the molecules, resulting in the highest-lying values for o-DPP-F-PhCN. A relatively enhanced and red-shifted UV–vis absorption of o-DPP-FPhCN indicated its stronger molecular aggregation. PSCs based on two DPP-F-PhCNs exhibited similar device efficiencies. The stronger aggregation behavior of o-DPP-F-PhCN led to a device with a better external quantum efficiency profile; however, the enhanced orbital interactions and resulting stabilized the lowest unoccupied molecular orbital level of o-DPP-F-PhCN led to a relatively low open-circuit voltage.

목차 (Table of Contents)

• 초록
• Abstract
• Introduction
• Experimental
• Results and Discussion
• Conclusions
• References

참고문헌 (Reference)

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