Experimental and theoretical investigations on chalcones containing pyrene

Involvement of halogen and polyaromatic substituents in chalcone derivatives as dye sensitizers in solar cell applications

“…This is similar to the previously reported C-H stretching band of pyrene-based chalcones, which appeared at 3041 cm À1 as a weak-intensity band. 23,29 Besides, PyF contains a methyl group (-CH 3 ), which was confirmed by the stretching vibrations at 2961 cm À1 . This vibrations mode agrees with the expected range of 2850-3000 cm À1 for symmetric and asymmetric C-H stretching.…”

“…1) began with the preparation of TiO 2 on glass for each sample. 16,23,24 The designated TiO 2 on glass was immersed in the dye solution, which was prepared by dissolving 10 À2 M of the precipitate in 5 mL of acetonitrile overnight for both compounds. Then, the remaining dye solution was dropped onto the TiO 2 area using the drop-casting technique with the presence of hot airflow to dry the sample.…”

“…CV studies were conducted to discover the oxidation and reduction properties of the synthesized PyBr and PyF. 16,23,24 A Three-electrode system with the proposed sample as the working electrode, a platinum electrode as the counter electrode, and an Ag/AgCl electrode as the reference electrode was employed during this study. 16 The cyclic voltammograms of all compounds are listed in Fig.…”

“…49 PyF possessed a lower E onset ox of 0.32 V, indicating that the presence of the strong electron-donating -OCH 3 substituent group caused less occurrence of oxidation, thus leading to lower potential values. 23 As for the reduction states, the cathodic peaks are formed due to the flow of donated electrons during the oxidation process; poor cathodic peaks correspond to electron oxidation before being reduced. 49 Hence, this indicates that the reason for the weak cathodic peaks of PyBr and PyF is the lack of electron transfer to undergo the reduction process.…”

“…The E onset ox and E onset red values were applied to calculate the HOMO and LUMO energy levels, respectively. 23,24 The HOMO and LUMO of PyBr and PyF were calculated and are illustrated in Fig. 8.…”