Molecular Engineering for Enhancing the Dielectric and Optoelectronic Properties of Antimony Corroles

Herein, the role of molecular engineering on the optoelectronic properties of antimony corroles with two distinct β-substituents and two different antimony oxidation states is studied. Insertion of a strong electron-withdrawing SCN group on the bi-pyrrole unit of the corrole increases the molecular dipole moment. Consequently, the dielectric constant is enhanced by up to threefold, reaching a value of 8 for antimony(V) tetra(thiocyano)corrole, significantly higher than any solution-processable organic semiconductor reported to date. Moreover, this SCN-substituted molecule also exhibits an increased charge carrier mobility by at least two orders of magnitude. A combination of suitable metallic oxidation state and SCN substitution is crucial in defining absorption, charge carrier mobility, and dielectric constant, all of which impact photovoltaic performance. The fluorescence quantum yield of the champion molecule increases by 300%, and the charge carrier lifetime is extended by twofold, indicating fewer nonradiative recombination pathways or a lower degree of disorder. Consequently, single-component photodetectors with white light responsivity as high as 10 A W^-1, ranking among the best in single-component donor-based organic semiconductors, and a single-component solar cell fabricated from antimony(V) tetra(thiocyano)corrole that exhibits an open-circuit voltage of 0.7 V, at least three times higher than single-component poly(3-hexylthiophene) (P3HT)-based photovoltaic devices, are demonstrated.