TD-DFT insights into the sensing potential of the luminescent covalent organic framework for indoor pollutant formaldehyde.

This paper investigates the sensitivity of the luminescent thieno[2,3- b ]thiophene-based covalent organic framework (TT-COF) towards the formaldehyde using the density functional theory and time-dependent method. The hydrogen bonding dynamics is explored by comparison of geometries, electronic transition energies, binding energies, UV–vis, and infrared spectra. Frontier molecular orbitals examination, natural population analysis, and plotted electron density difference map describe the quenching process explicitly via electron density distribution. The MOMAP program illuminates the quenching owing to TT-COF-HCHO complex radiative rate constant. Furthermore, the S1-T1 energy gap describes the facilitation of the luminescence quenching through the intersystem crossing. Above all results elaborate the TT-COF's potential to detect the formaldehyde. Unlabelled Image • TD-DFT investigation for intermolecular hydrogen bonding dynamics • Excited-state hydrogen bond complex shows redshift • The fluorescence of TT-COF is quenched due to enhanced hydrogen bonding • Energy gap facilitates the intersystem crossing process [ABSTRACT FROM AUTHOR]