Raman and IR spectra of a 2D Thiophene-Tetrathia-Annulene monolayer calculated via density-functional theory

Monolayers of two-dimensional polymers (2DP) offer an ideal system in the scope of application, as their electronic properties can be tuned at the molecular level. One of the key challenges in to insure a 2DP synthesis quality at the large scale. Here we calculate Raman and infrared (IR) spectra of recently proposed new two-dimensional semiconductor material based on the molecular structure of Thiophene-Tetrathia-Annulene (TTA) and compare it with an isolated single TTA molecule and a dimer. Significant transformation of Raman and IR spectra of individual TTA molecules during transition to a 2D layer was observed. The calculations evidence the possibility of use Raman and IR spectroscopy as an efficient and reliable tool for synthesis and quality control of TTA-2D layer at the large scale. •IR and Raman spectra allows to confirm synthesis of 2D TTA monolayer.•Size and quality of TTA-2D clusters my be monitored in-operando.•High-range frequency peaks provide information on the dehydrogenation process.•Identification of closed 4, 6 and 8 carbon atoms rings formation.