SYNTHESIS OF NEW NITROBENZYLIDENE DERIVATIVES AND PYRROLE-BASED COPOLYMERS FOR DYE-SENSITIZED SOLAR CELLS: EFFECT OF SUBSTITUENT ON OPTO-ELECTRICAL PROPERTIES OF DIP-COATED THIN FILMS

The mastery of the optoelectronic properties of conjugated copolymers by substituting their radicals is a promising way for increasing the light absorption and charge career transport in the organic devices active layer. In this paper, we present the chemical synthesis of four different conjugated benzaldehyde derivatives and pyrrole-based copolymers (P-P:B) followed by their conception in thin films on glass substrates by dip coating root from a solution in dichloromethane. UV-Vis measurements showed absorption in good part of the visible region, with an optical gap around 2 eV. Morphological properties observed by scanning electron microscope of the four P-P: B based thin films illustrated homogenous and continuous surfaces with roughness and surface shape that can be modulated according to Nitrobenzylidene derivative that contains the copolymer. First oxidation (E-p) and reduction (E-n) potentials of synthetized copolymers have been estimated by cyclic voltammetry which led us to estimate the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), respectively. The HOMO and LUMO energy level diagram of P-P:B compared with the most commonly used organic materials as donor/acceptor couples showed a cascade shape, which allowed us to opt for organic solar cells based on multiple active layers in our aim to improve its performance.