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Abstract Design strategies to achieve degradation and ideally closed‐loop recycling of organic semiconductors have attracted great interest in order to minimize the electronic waste (E‐waste). In this work, three ester‐incorporated monomers were synthesized by the names of Thiophene‐Ester‐Ethylene‐Thiophene (TEET), Thiophene‐Ester‐Methylene‐Thiophene (TEMT), and Thiophene‐Ester‐Thiophene (TET), which were co‐polymerized via Stille polycondensation with a benzodithiophene (BnDT) π‐conjugated unit to yield a series of ester‐incorporated polymers: PBnDT‐TEET, PBnDT‐TEMT, and PBnDT‐TET. While the ester‐only linker can maintain some extended conjugation in PBnDT‐TET, the other two ester linkers having conjugation breaking units result in isolated conjugated segments in PBnDT‐TEET and PBnDT‐TEMT, evidenced by UV‐Vis and CV results. This yields an improved photovoltaic performance of PBnDT‐TET compared to PBnDT‐TEET. While all three polymers can depolymerize under methanolysis, the alternating co‐polymer PBnDT‐TEET demonstrates the highest recyclability potential with a single dimethyl ester‐functionalized product with an excellent 92 % isolated yield, which can then be repolymerized to reobtain PBnDT‐TEET with a 36 % yield. This work provides a framework towards achieving recyclable organic semiconductors to reduce E‐waste. Although the incorporation of ester linkers allowed for closed‐loop recycling, the low solar cell efficiency of PBnDT‐TEET highlights the significant challenge in achieving both recycling and high device performance.
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Further Proof of Unconventional Conjugation via Disiloxane Bonds: Double Decker Sesquioxane [vinylMeSi(O 0.5 ) 2 (PhSiO 1.5 ) 8 (O 0.5 ) 2 SiMevinyl] Derived Alternating Terpolymers Give Excited-State Conjugation Averaging That of the Corresponding Copolymers
Here, we report the synthesis of DD SQ terpolymers with alternating biphenyl/terphenyl/stilbene and thiophene/hexylthiophene/bithiophene/thieno- thiophene linkers. These terpolymers were characterized using 1H and 13C nuclear magnetic resonance, gel permeation chromatography, matrix-assisted laser desorption/time-of-flight spectrometry, thermogravimetric analysis, and Fourier- transform infrared with the goal of combining long-wavelength emissions with high quantum yields. Density functional theory modeling studies using the Vienna ab initio simulation package and Gaussian 16 methods were also explored in attempts to determine HOMO-LUMO electronic configurations. Terpolymers’ UV−vis properties demonstrate an emission intermediate between the respective copolymers rather than emission from both units as would be expected from physical mixtures, supporting electronic communication along polymer chains and through cages linked via disiloxane units as seen in previous reports on copolymers of the same systems. In addition, terpolymers of DD, thiophene, and terphenyl/ stilbene offer ΦF that improved from 0.09 for DD/thiophene to 0.20 and 0.24, respectively. Compared to the corresponding terphenyl and stilbene copolymers, terpolymers display 35 nm red-shifted emissions, suggesting that it is possible to combine features of both copolymers in a single terpolymer, suggesting new opportunities to tailor photophysical properties by modifying structures, especially in systems with disiloxane linkers.
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- Award ID(s):
- 2103602
- PAR ID:
- 10525819
- Editor(s):
- Hillmyer, M
- Publisher / Repository:
- American Chemical Society
- Date Published:
- Journal Name:
- Macromolecules
- Edition / Version:
- 1
- Volume:
- 55
- Issue:
- 18
- ISSN:
- 0024-9297
- Page Range / eLocation ID:
- 8106 to 8116
- Subject(s) / Keyword(s):
- terpolymers, conjugation, silsesquioxanes, double decker, photophyics
- Format(s):
- Medium: X Size: 3.4 Other: cxv
- Size(s):
- 3.4
- 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/10.1021/acs.macromol.2c01355
