Insights into Bulk‐Heterojunction Organic Solar Cells Processed from Green Solvent
Abstract
The environmental impact of solution processed organic solar cells (OSCs) can be mitigated by introducing so‐called green solvents during the fabrication processes. However, the effects of such green solvents on the molecular‐level structures and optoelectronic properties lack in‐depth characterization. Here, insights into the structure–processing–property correlation of a PPDT2FBT:PC61BM bulk‐heterojunction (BHJ) system processed from a green solvent, ortho‐xylene (o‐XY), is investigated in comparison with the same blend processed from a traditional halogenated solvent, chlorobenzene (CB). The BHJ blends are characterized with various techniques probing at difference length scales, and an increased donor:acceptor (D:A) interfacial area as well as well‐mixed features in the bulk morphologies of the active layer are observed for the o‐XY processed BHJ blend. Furthermore, molecular‐level differences in the D–A intermolecular interactions at the BHJ interfaces in o‐XY and CB cast films are elucidated by 2‐dimensional solid‐state nuclear magnetic resonance (ssNMR) measurements and analysis. These results are consistent with the device properties, suggesting that the green‐solvent‐processed devices have longer charge carrier lifetimes and faster charge carrier extraction. The optimized PPDT2FBT:PC61BM devices processed from o‐XY can achieve a noteworthy higher power conversion efficiency (PCE) owing to a higher short‐circuit current density and fill factor.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jun 03, 2021
- Source ID
- 10.1002/solr.202100213
Entities
People
- Alana L. Dixon
- G N Manjunatha Reddy
- Harald Ade
- Jianfei Huang
- Joachim Vollbrecht
- Mario Leclerc
- Mathieu Mainville
- Max Schrock
- Nora Schopp
- Sangmin Chae
- Thuc-Quyen Nguyen
- Zhengxing Peng
- Zhifang Du
Organizations
- Alexander von Humboldt Foundation
- Laval University
- Natural Sciences and Engineering Research Council
- North Carolina State University
- Office of Naval Research
- University of California, Santa Barbara
- University of Lille