Molecular engineering and synthesis of symmetric metal-free organic sensitizers with A-π-D-π-A architecture for DSSC applications: the effect of bridge unit
Herein, we report the design and synthesis of six symmetric metal-free organic sensitizers ( llyu1a, llyu1b, llyu1c, llyu2a, llyu2b, and llyu2c ) based on fluorene or dimethyl fluorene donors core carrying double acceptors. All these dyes were characterized using UV–Vis, ESI-MS, and 1 HNMR. To study...
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Published in | Journal of the Iranian Chemical Society Vol. 16; no. 11; pp. 2441 - 2450 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Berlin/Heidelberg
Springer Berlin Heidelberg
01.11.2019
Springer Nature B.V |
Subjects | |
Online Access | Get full text |
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Summary: | Herein, we report the design and synthesis of six symmetric metal-free organic sensitizers (
llyu1a, llyu1b, llyu1c, llyu2a, llyu2b,
and
llyu2c
) based on fluorene or dimethyl fluorene donors core carrying double acceptors. All these dyes were characterized using UV–Vis, ESI-MS, and
1
HNMR. To study the influence of π-bridges on total solar-to-electric conversion efficiency (%
η
) for DSSCs, three different π-bridges thiophene, furane, or benzene were introduced into the sensitizers. Their device performances were studied and showed a distinctive difference in efficiency with a maximum of PCE of 2.35% (
Jsc
= 5.63 mA cm − 2,
V
OC
= 0.60 V and
FF
= 70.00%) for dye
llyu1a
. Density functional theory (DFT) and time-dependent density functional theory calculations were used to probe the relationship between chemical structure, photophysical, and photoelectrochemical properties. DFT studies showed that the dihedral angle between thiophene and donor is 26.6°, indicating that the dyes bearing thiophene π-bridge possess more efficient photoexcitation compared to dyes bearing benzene π-bridge (36.6° for both
llyu2c
and
llyu1c
) and less aggregation than dyes bearing furane π-bridge (0° for
llyu1b
and
llyu2b
). This new finding of influence of π-bridges on total solar-to-electric conversion efficiency would open the door for the molecular engineering of better light harvesting and more efficient metal-free organic sensitizers for DSSCs. |
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ISSN: | 1735-207X 1735-2428 |
DOI: | 10.1007/s13738-019-01713-3 |