Effect of fluorine substituted benzothiadiazole on electro-optical properties of donor-acceptor-donor type monomers and their polymers

ÇAKAL D., Ercan Y. E., ÖNAL A. M., CİHANER A.

DYES AND PIGMENTS, cilt.182, 2020 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 182
  • Basım Tarihi: 2020
  • Doi Numarası: 10.1016/j.dyepig.2020.108622
  • Dergi Adı: DYES AND PIGMENTS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Chimica, Communication Abstracts, Compendex, INSPEC, Metadex, Civil Engineering Abstracts
  • Anahtar Kelimeler: Donor-acceptor-donor approach, Fluorination, Benzothiadiazole, Thiophene, ORGANIC SOLAR-CELLS, ELECTROCHROMIC PROPERTIES, CHARGE-TRANSPORT, OPTOELECTRONIC PROPERTIES, CONJUGATED POLYMERS, COPOLYMERS, PERFORMANCE, THIOPHENE, MOIETY, DEVICE
  • Orta Doğu Teknik Üniversitesi Adresli: Evet

Özet

A series of trimeric monomers bearing thiophene donor units and fluorinated analogues of benzothiadiazole acceptor units was synthesized via donor-acceptor-donor approach and polymerized electrochemically in order to investigate the effect of fluorine atom on electro-optical properties of both monomers and their corresponding polymers. All monomers exhibited solvatochromic and fluorescent properties. The introduction of fluorine atom into the conjugated backbone increased the oxidation potentials. Upon moving from nonfluorinated to fully fluorinated analogues, the oxidation potential shifts anodically from 1.30 V to 1.7 V. As in the case of monomers, the fluorine atom substitution also resulted in a decrease in the HOMO energy level of the corresponding polymers, leading to an increase in the electrochemical band gap energy (1.71-1.97 eV). This result can be attributed to deviations from planarity and also to decrease in the effective conjugation length. The polymeric film also exhibited electrochromic properties under various external potentials. Switching time and coloration efficiency values decreased with increasing number of fluorine atom substitution.