Publication

Abstract : A multifunctional tetrazine-integrated π-conjugated two-dimensional (2D) porous organic polymer (CMP) (PTz) has been developed by the self-condensation of benzene-1,3,5-tricarbonitrile in the presence of sulfur and hydrazine hydrate via the Pinner synthetic strategy. PTz has been further postmodified into a pyridazine polymer (PPz) through an inverse electron demand Diels–Alder (IEDDA) reaction using ethyl vinyl ether, which allows the tuning of structural, optical, and electronic properties. DFT revealed a 0.6 eV difference in band gap between the two polymers, with PTz having a narrow band gap of 1.6 eV and PPz having a band gap of 2.2 eV. Furthermore, PTz is a red solid with an absorption red edge at 620 nm, whereas PPz produces a yellow solid with a blue-shifted absorption red edge of 480 nm. 2D PTz was utilized to form a resistive sensor for detecting NO2, a prominent environmental pollutant. PTz exhibited an excellent sensitivity toward NO2, with its response varying from −8.4 to −34.2% for 2–10 ppm of NO2 at room temperature. The detection limit of PTz was found to be 337 ppb, and the response time and recovery time ranged from 176 to 273 s and 307 to 443 s, respectively, for a concentration range of 2 to 10 ppm of NO2. The polymer exhibited high selectivity toward NO2 among different tested analytes (CO, SF6, NH3, H2O, and H2S).