Thienothiophene and triazine decorated conjugated materials incorporating various functional groups: Design, synthesis, photophysical and charge transport properties

Organic triazine frameworks (CTFs) have been instrumental in providing electronic conductive and semi-conductive materials with superior performance for various applications, including solar cells, capacitors, hydrogen production/storage, cancer therapy, bacterial treatment via photosensitizers, chemical sensors and light-emitting diodes. Organic porous polymers serve as non-crystalline analogues of CTFs and are extensively studied in material science due to their straightforward design, utility and versatility. This study introduces the design and synthesis of novel triazine-type porous polymers (P1-P6), and their conjugated monomers (M1-M6), composed of thienothiophene (TT) ring as π-bridges alongside cyanophenyl, methoxyphenyl and heptyl as donor-acceptor (D-A) functional groups. The polymers were synthesized by acid catalyzed trimerization. Optical characteristics of the monomers (M1-M6) and polymers (P1-P6), as well as their surface morphologies and photoconductive behaviors were investigated employing UV-Vis and fluorescence measurements and SEM, BET and FP-TRMC analyses. Within the examined covalent triazine frameworks, the heptyl chain-substituted polymer P6 displayed the lowest optical band gap (2.84 eV), and the highest conductivity φ∑µ in both its undoped (5 × 10^–6 cm² V^–1 s^–1) and I₂-doped (1 × 10^–5 cm² V^–1 s^–1) states.