New cyanopyridine based conjugated polymers carrying auxiliary electron donors: From molecular design to blue emissive PLEDs

• Published in: Dyes and pigments 2020-03, Vol.174, p.108046, Article 108046
• Main Authors: Pilicode, Naveenchandra, Naik, Praveen, Nimith, K.M., Acharya, Madhukara, Satyanarayan, M.N., Adhikari, Airody Vasudeva
• Format: Article
• Language: English
• Subjects: Blue light emitter; Cyanopyridine; DFT; Donor-acceptor; Electroluminescence
• ISSN: 0143-7208; 1873-3743
• DOI: 10.1016/j.dyepig.2019.108046

Three new D-A (Donor-Acceptor) configured conjugated polymers, i.e.PPy1-3, centered on strong electron accepting cyanopyridine scaffold carrying varied auxiliary donors, viz. phenylene (PPy1), biphenyl (PPy2), and fluorene (PPy3) were designed and synthesized as blue emitters for PLEDs. The new polymers were subjected to spectral, thermal, photophysical and electrochemical characterization. Also, computational studies (DFT) were performed on the repeating units of polymer using Turbomole 7.2 V software package at the B3LYP/TZVP hybrid levels. Further, their weight average molecular masses were found to be 38.8 kDa, 38.9 kDa and 57.7 kDa, respectively as determined by GPC technique. Furthermore, the new polymers PPy1-3, were shown to be stable thermally up to 308–374 °C. Evidently, they exhibited good photophysical behavior with their optical energy band gaps of 2.53–2.64 eV. Finally, the polymers PPy1-3 were employed as an active emissive layer in standard ITO/PEDOT:PSS/Polymer/Al configured PLEDs. Interestingly, at 12 V all the newly fabricated devices exhibit a stable blue characteristic electroluminescence with low threshold voltages of 3.40–5.20 V, confirming an efficient injection of electrons in the diodes. From the results, it is clear that, the polymers PPy1-3, can be considered as prospective blue light emitters for PLED application. Three new cyanopyridine based conjugated polymers, PPy1-3 were designed, synthesized and well-characterized as potential blue emissive materials for PLED application. The detailed studies on their thermal, photophysical, electrochemical, theoretical and electroluminescence properties reveal that, the polymers possess all the prerequisites for the device application. [Display omitted] •Synthesized three new cyanopyridine based conjugative polymers PPy1-3 for PLED•Show light absorption maxima at 365-380 nm and blue emission at 412-442 nm•Display optical band gap of 2.53-2.64 eV with florescence quantum yield 39-49%.•·Fabricated ITO/PEDOT:PSS/Polymer/Al configured devices with stable polymers .•Electroluminescence maxima appears  at 425-452 nm with low threshold voltage.