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Abstract Photoresponsive conjugated polymers are a promising target for modern organic electronics. Numerous photoswitchable repeat units have been included covalently within polymeric structures to enable responsive chromic materials, most commonly through side‐chain appendages or through formal conjugation along a π‐conjugated backbone. We recently disclosed a new design whereby the photoswitch elements are cross conjugated to a conjugated polymer main chain. In this case, we found that the extent of photoconversion was dictated in part by competitive main chain light absorption, which could be suppressed by using a photoswitching motif that carried most of the frontier molecular orbital densities. Here, we report the modeling and synthesis of a series of thieno[3,4‐b]thiophene (TT)‐based photochromes with various aromatic flankers imparting varying degrees of steric bulk and π‐conjugation in order to elucidate the balancing act between steric and electronic factors to promote photochromism. These model systems provide a better understanding of the behavior of photochromic units within extended oligomeric and polymeric π‐conjugated materials.
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Panchromatic cross-conjugated π-bridge NIR dyes for DSCs
Four organic sensitizers incorporating a cross-conjugated cyclopenta[2,1- b :3,4- b ′]dithiophene (CPDT) π-bridge have been synthesized. As a result of molecular engineering, broad high energy bands and red shifted absorption maxima and onset is observed relative to a benchmark analogue ( C218 ) using a non-cross-conjugated CPDT π-bridge. The use of a cross-conjugated bridge allows a new strategy for tuning dye energetics and introduction of increased absorption uniformity by adding additional high-energy absorption bands. These dyes show solar-to-electric conversion up to 800 nm with one derivative exceeding the performance of C218 under identical conditions.
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- Award ID(s):
- 1632825
- PAR ID:
- 10057221
- Date Published:
- Journal Name:
- Physical Chemistry Chemical Physics
- Volume:
- 20
- Issue:
- 4
- ISSN:
- 1463-9076
- Page Range / eLocation ID:
- 2438 to 2443
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/C7CP06703H
