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 semiconductive 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 pi-bridges alongside cyanophenyl, methoxyphenyl and heptyl as donoracceptor (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 phi & sum;mu in both its undoped (5 x 10-6 cm2 V-1 s-1) and I2-doped (1 x 10-5 cm2 V-1 s-1) states.