Abstract
Fabrication of high-efficiency organic solar cells (OSCs) using nonhalogen green solvents is highly desired for commercialization. However, the morphology control of a nonhalogen solvent-processed active layer remains challenging because of poor solubility of the commonly used photovoltaic materials in nonhalogen solvents. Herein, we propose a two-step heating strategy to optimize the morphology of a photovoltaic active layer based on a low-cost polymer donor X1 and a small-molecule acceptor (SMA) BTP-eC9 processed from a mixed nonhalogen solvent. First, heating the blend solution can robustly enhance the solubility of the SMA and thus processability of the blend, producing a uniform active layer. Second, further elevating the substrate temperature can shorten the film-formation time and tune the size of the polymer aggregates and SMA crystallites, to form bicontinuous networks in the active layer. As a result, this two-step heating strategy endows the film with improved charge generation, transport, and collection and thus a much higher device efficiency (ca. 4.6 times of that for the as-cast device) in comparison to those from nonoptimal solution and/or substrate temperatures. This work emphasizes the crucial role of regulating processing conditions in fabricating the nonhalogen solvent-processed high-efficiency OSCs.
Original language | English |
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Pages (from-to) | 867-875 |
Number of pages | 9 |
Journal | Macromolecules |
Volume | 56 |
Issue number | 3 |
DOIs | |
Publication status | Published - 2023 Feb 14 |
Bibliographical note
Publisher Copyright:© 2023 American Chemical Society. All rights reserved.
ASJC Scopus subject areas
- Organic Chemistry
- Polymers and Plastics
- Inorganic Chemistry
- Materials Chemistry