Experimental and theoretical investigations on structural-function relationship of new iron (III) complex with 2-(Ammoniomethyl)pyridinium cation as ligand: A promising material for green solar cells

International audience; Crystals of (H2AMP)2[FeIIIBr4]Br3, where AMP refers to the 2-(Ammoniomethyl)pyridinium ligand, have been successfully synthesized through redox chemistry and analyzed using X-ray crystallography. The new complex crystallizes as red needles in the monoclinic space group, P21/c, with eight formula weights in a unit cell of dimensions: a = 12.358 (13), b = 28.572 (3), c = 13.544 (14) Å and β=92.009(5) °. Analysis of absorption and reflectance data through the visible and near-infrared provide insight into the optical properties of the material. The structural data and the BVS (Bond Valence Sum) calculations are in agreement with the iron (III) oxidation. In this work, the experimental and theoretical study on molecular structure and vibrational spectral analysis of the new product has been reported. Theoretical calculations were performed by using density functional theory (DFT) at the B3LYP/LAN2DZ basis set levels. The electronic parameters such as frontier molecular orbital, electrostatic potential and HOMO-LUMO energy were calculated. Also, NLO were studied with the same level of DFT. The theoretical values show good agreement with experimental values. In addition, (H2AMP)2[FeIIIBr4]Br3 reveals broad absorption across the visible spectrum and an optical bandgap of 1.06 eV. Then the obtained material can be a promising eco-friendly light absorber in solar cell application. Finally, the thermal behavior of this material has been performed by TGA/DTA. In addition, two phase transitions at T1 = 108 °C and T2 = 170 °C were evidenced by DSC measurements.