DFT and TDDFT investigations of photovoltaic properties of triphenylamine based dyes: Impact of π based redox shuttle -spacer tuning for DSSC with iodine and copper
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Date
2026
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Abstract
A series of dyes with a donor
π-acceptor (D
π-A) framework based on triphenylamine (TPA) were theoretically
designed to enhance the photovoltaic performance of dye-sensitized solar cells (DSSCs). Based on an experi
mentally reported TPA dye containing a benzo[c][1,2,5] thiadiazole(Dye1)
modelled by including benzo[c]thiophene(Dye2), 4,4
′
π-spacer, five new dyes were -bibenzo[c]thiophene(Dye3), 2H-benzo[d][1,2,3]triazole
′
H-4,4
′
(Dye4), 2H,2
azole(Dye6) as
π-bibenzo[d][1,2,3]triazole(Dye5), and 4-(benzo[c]thiophen-4-yl)-2H-benzo[d][1,2,3]tri--spacers. Density Functional Theory and Time-Dependent Density Functional Theory were
employed to study their electronic structures, charge transfer properties, and photovoltaic performance. All dyes
showed negative Gibbs free energy for electron injection into TiO
2
, signifying favourable charge transfer. The
dye2 with benzo[c]thiophene spacer exhibited the highest open-circuit voltage, while those with dye5 and dye6
showed faster regeneration, particularly with copper-based redox shuttles. These candidates demonstrated high
light-harvesting efficiency and ideal energy alignment, indicating their potential for high-efficiency DSSCs. These
f
indings show that the
π-spacer tuning is an effective strategy for optimizing dye performance in DSSCs.