DFT/TDDFT studies on carbazole-antipyrine Schiff base organic dyes containing different πi-spacer for DSSCs applications

Abstract

A series of organic dyes (W1-W12) with antipyrine and carbazole moieties as donor, thiophene derivatives (πi) and phenyl (π) as π-spacer and carboxyl group as acceptor were investigated theoretically based on the synthetic compounds WLE1 and WLE2. The calculated results revealed that the introduction of πi-spacers between antipyrine and carbazole moieties can significantly reduce HOMO and LUMO energy gap, and leading to the λmax red-shift and ƒ significantly increased. The designed dyes exhibit good photovoltaic performance, such as higher VOC, good LHE performance, negative values of ΔGinj, and smaller values of ΔGreg, which can lead to a higher JSC and hence a greater PCE. Especially, the dyes W9 and W12 could be the excellent candidate for high efficiency DSSCs applications. We further used (TiO2)6 as model semiconductor to evaluate the overall optoelectronic properties and transport parameters of the dye/TiO2 assembly after anchoring the dyes on the model TiO2 cluster.