The impact of structural modification on the electrochromic and electroluminescent properties of D–A–D benzothiadiazole derivatives with a fluorene linker and (Bi)thiophene units

Ganczarczyk, Roman; Rybakiewicz-Sekita, Renata; Zawadzka, Magdalena; Pander, Piotr; Ledwon, Przemysław; Nastula, Dawid; Pluczyk-Małek, Sandra

Abstract

Two donor–acceptor–donor (D–A–D) derivatives of benzothiadiazole (BTD) symmetrically functionalized with dihexylfluorene units serving as a linker between the BTD core and the thiophene (Th-FBTD) or bithiophene (2Th-FBTD) electron-donating groups were designed, synthesized and comprehensively characterized. Both compounds show high photoluminescence quantum yield (PLQY) both in solution and in the solid state. Th-FBTD demonstrates PLQY values of 82% and 96%, whereas 2Th-FBTD exhibits values of 74% and 97% in DCM and Zeonex, respectively. These compounds were employed as emissive dopants in multilayer solution-processed OLEDs, resulting in green electroluminescence with an emission peak at ca. 540 nm. The OLEDs display comparable performance, with a maximum external quantum efficiency of 3.5% for Th-FBTD and 2.8% for 2Th-FBTD. Both Th-FBTD and 2Th-FBTD undergo quasi-reversible electrochemical reduction and irreversible oxidation, giving stable electroactive polymer layers of bipolar character: p(Th-FBTD) and p(2Th-FBTD). The electrodeposited polymers undergo one-step reversible reduction and two-step reversible oxidation. Their electrochemical oxidation is accompanied by a reversible color change. Analysis of the optical density difference and coloration efficiency revealed improved electrochromic properties in both visible and near-infrared (NIR) ranges in p(2Th-FBTD) compared to that in p(Th-FBTD).

Citation

Ganczarczyk, R., Rybakiewicz-Sekita, R., Zawadzka, M., Pander, P., Ledwon, P., Nastula, D., & Pluczyk-Małek, S. (2024). The impact of structural modification on the electrochromic and electroluminescent properties of D–A–D benzothiadiazole derivatives with a fluorene linker and (Bi)thiophene units. Journal of Materials Chemistry C Materials for optical and electronic devices, 12(37), 15201-15214. https://doi.org/10.1039/d4tc01583e

• Journal Article Type: Article
• Acceptance Date: Aug 5, 2024
• Online Publication Date: Sep 2, 2024
• Publication Date: Oct 7, 2024
• Deposit Date: Sep 13, 2024
• Publicly Available Date: Sep 13, 2024
• Journal: Journal of Materials Chemistry C
• Print ISSN: 2050-7526
• Electronic ISSN: 2050-7534
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 12
• Issue: 37
• Pages: 15201-15214
• DOI: https://doi.org/10.1039/d4tc01583e
• Public URL: https://durham-repository.worktribe.com/output/2819420