| Title: |
State Diagrams of PBTTT Derivatives Mixed with PC61BM and Their Relevance for Organic Electronics: Influence of Incongruently Melting Co-crystals and Homocoupling Defects |
| Authors: |
Liu, Zhen; VANDERSPIKKEN, Jochen; VANDEWAL, Koen; MAES, Wouter; Goderis, Bart; Nies, Erik; van den Brande, Niko; Van Mele, Bruno |
| Contributors: |
Liu, Zhen; VANDERSPIKKEN, Jochen; VANDEWAL, Koen; MAES, Wouter; Goderis, Bart; Nies, Erik; van den Brande, Niko; Van Mele, Bruno |
| Publisher Information: |
WILEY-V C H VERLAG GMBH |
| Publication Year: |
2025 |
| Collection: |
Document Server@UHasselt (Universiteit Hasselt) |
| Subject Terms: |
eutectic-peritectic; homocoupling-free alternating conjugated polymers; intercalation; rapid heat-cool DSC; temperature-resolved synchrotron XRD |
| Description: |
Double binary state diagrams of the benchmark semi-crystalline conjugated polymer PBTTT and its alkoxy derivatives PBTTT-OR-R and PBTTT-(OR)(2), mixed with PC61BM, are constructed using Rapid Heat-Cool Differential Scanning Calorimetry and T-resolved synchrotron X-Ray Diffraction. The polymerization method is adapted to ensure the absence of homocouplings and obtain reliable state diagrams, supported by Flory-Huggins calculations. Co-crystallization always occurs at a 45:55 w/w% polymer:PC61BM mixing ratio. All co-crystals remain stable up to 260-280 degrees C in a wide composition range, and for the first time, it is proven that they show incongruent (peritectic) melting. The three state diagrams show one eutectic, i.e., between polymer and co-crystal in the case of PBTTT and PBTTT-OR-R, and between polymer and PC61BM for PBTTT-(OR)(2). The latter eutectic beyond 280 degrees C leads to a reversible "solid-solid" transformation with the corresponding co-crystal. Isothermal treatments, at the onset temperature of co-crystallization during non-isothermal cooling, show no loss of co-crystal quality in combination with PC61BM perfectioning for fullerene-rich PBTTT:PC61BM and PBTTT-OR-R:PC61BM mixtures, whereas PBTTT-(OR)(2):PC61BM, as well as Stille-polymerized PBTTT-OR-R:PC61BM with homocouplings, show suppression of co-crystallization with the formation of separate crystals of polymer and PC61BM. These opposing effects are explained by the state diagrams, showcasing their substantial value in selecting efficient annealing conditions. ; The authors thank the Research Foundation – Flanders (FWO Vlaanderen) for financial support (Ph.D. project 1S50822N, project G0B2718N, and DUBBLE project I001919N). |
| Document Type: |
article in journal/newspaper |
| File Description: |
application/pdf |
| Language: |
English |
| ISBN: |
978-0-01-434603-5; 0-01-434603-6 |
| Relation: |
Small, 21 (13) (Art N° 2410993); https://hdl.handle.net/1942/45657; 13; 21; 001434603600001 |
| DOI: |
10.1002/smll.202410993 |
| Availability: |
https://hdl.handle.net/1942/45657; https://doi.org/10.1002/smll.202410993 |
| Accession Number: |
edsbas.2434816F |
| Database: |
BASE |