Journal Paper

Molecular design offers a powerful approach to improve the performance of organic solar cells by tuning the
electronic properties of active molecules and optimising the morphology of their thin films. Barbituric acid and
its derivatives, as electron-withdrawing moieties in non-fullerene acceptors (NFAs), have shown promise in
improving the performance in organic photovoltaics (OPVs). Here, the synthesis of four novel NFAs with barbituric
acid and N-methyl barbiturate derivatives end-groups, via microwave-assisted Knoevenagel condensation
reactions, is described. The optical properties, electrochemical analysis, and theoretical calculations of the new
acceptors were systematically investigated, providing deep insights into their electronic structure. Solar cells
incorporating the new materials as acceptors both in binary and ternary active blends were fabricated and their
performances were correlated with the film morphology of the photoactive blends, assessed by atomic force
microscopy. This work elucidates on the significant role of barbituric acid and their derivatives in the molecular
design of novel acceptors for thin-film optoelectronic devices such as organic solar cells.