Influence of 3D morphology on the performance of all-polymer solar cells processed using environmentally benign nonhalogenated solvents
- 주제(키워드) Active layer morphology , All-polymer solar cell , Environmentally benign solvent/additive , Molecular dynamics simulation , TEM tomography
- 등재 SCIE, SCOPUS
- 발행기관 Elsevier Ltd
- 발행년도 2020
- 총서유형 Journal
- URI http://www.dcollection.net/handler/ewha/000000169539
- 본문언어 영어
- Published As https://dx.doi.org/10.1016/j.nanoen.2020.105106
- 저작권 이화여자대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Advancing the photovoltaic performance of all-polymer solar cells (APSCs) requires a comprehensive understanding of the dependence of the properties of photoactive blend films on the solvents used to process them. We have studied the correlation between the morphology of PTB7-Th:PNDI2OD-T2 blend films prepared using six different processing solvents. Three-dimensional (3D) transmission electron microscopy tomography (TEMT) revealed the influence of the 3D morphology of the PTB7-Th:PNDI2OD-T2 blend films on their photovoltaic performance. The high-performing toluene (TOL)- and o-xylene (XY)-processed blend films displayed power conversion efficiencies (PCEs) of ~4%, which contained nanoscopically networked fibrous PNDI2OD-T2 polymer domains. The films processed using the other solvents exhibited partly disconnected domains or unfavorable vertical phase separation. In addition, the use of N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), or N-methyl-2-pyrrolidone (NMP) as a solvent additive in XY solution resulted in a substantial improvement in the PCEs to 6.1%. This large enhancement was attributed to the formation of the better-interconnected narrower crystalline fibrillary structure of PNDI2OD-T2 chains with the aid of solvent additives, as clearly elucidated by 3D-TEMT imaging. This work highlights that APSCs processed from benign nonhalogenated solvents with appropriate additives can outperform APSCs processed from toxic halogenated solvents by affording a favorable blend morphology and that 3D TEMT imaging is a powerful and essential tool for characterizing the true morphology of photoactive layers. © 2020 Elsevier Ltd
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