Abstract
Head-to-head linked bithiophenes with planar backbones hold distinctive advantages for constructing organic semiconductors, such as good solubilizing capability, enabling narrow bandgap, and effective tuning of frontier molecular orbital (FMO) levels using minimal thiophene numbers. In order to realize planar backbone, alkoxy chains are typically installed on thiophene head positions, owing to the small van der Waals radius of oxygen atom and accompanying noncovalent S...O interaction. However, the strong electron donating alkoxy chains on the electron-rich thiophenes lead to elevated FMO levels, which are detrimental to material stability and device performance. Thus, a new design approach is needed to counterbalance the strong electron donating property of alkoxy chains to bring down the FMOs. In this study, we designed and synthesized a new head-to-head linked building block, 4-alkoxy-5-(3-alkylthiophen-2-yl)thiazole (TRTzOR), using an electron-deficient thiazole to replace the electron-rich thiophene. Compared to previously reported 3-alkoxy-3′-alkyl-2,2′-bithiophene (TRTOR), TRTzOR is a weaker electron donor, which considerably lowers FMOs and maintains planar backbone through the noncovalent S...O interaction. The new TRTzOR was copolymerized with benzothiadiazoles with distinct F numbers to yield a series of polymer semiconductors. Compared to TRTOR-based analogous polymers, these TRTzOR-based polymers have broader absorption up to 950 nm with lower-lying FMOs by 0.2-0.3 eV, and blending these polymers with PC 71 BM leads to polymer solar cells (PSCs) with improved open-circuit voltage (V oc ) by ca. 0.1 V and a much smaller energy loss (E loss ) as low as 0.59 eV. These results demonstrate that thiazole substitution is an effective approach to tune FMO levels for realizing higher V oc s in PSCs and the small E loss renders TRTzOR a promising building block for developing high-performance organic semiconductors.
| Original language | English |
|---|---|
| Pages (from-to) | 35724-35734 |
| Number of pages | 11 |
| Journal | RSC Advances |
| Volume | 8 |
| Issue number | 62 |
| DOIs | |
| Publication status | Published - 2018 Jan 1 |
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ASJC Scopus subject areas
- Chemistry(all)
- Chemical Engineering(all)
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Polymer semiconductors incorporating head-to-head linked 4-alkoxy-5-(3-alkylthiophen-2-yl)thiazole. / Zhou, Xin; Chen, Peng; Koh, Chang Woo; Chen, Sheng; Yu, Jianwei; Zhang, Xianhe; Tang, Yumin; Bianchi, Luca; Guo, Han; Woo, Han Young; Guo, Xugang.
In: RSC Advances, Vol. 8, No. 62, 01.01.2018, p. 35724-35734.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Polymer semiconductors incorporating head-to-head linked 4-alkoxy-5-(3-alkylthiophen-2-yl)thiazole
AU - Zhou, Xin
AU - Chen, Peng
AU - Koh, Chang Woo
AU - Chen, Sheng
AU - Yu, Jianwei
AU - Zhang, Xianhe
AU - Tang, Yumin
AU - Bianchi, Luca
AU - Guo, Han
AU - Woo, Han Young
AU - Guo, Xugang
PY - 2018/1/1
Y1 - 2018/1/1
N2 - Head-to-head linked bithiophenes with planar backbones hold distinctive advantages for constructing organic semiconductors, such as good solubilizing capability, enabling narrow bandgap, and effective tuning of frontier molecular orbital (FMO) levels using minimal thiophene numbers. In order to realize planar backbone, alkoxy chains are typically installed on thiophene head positions, owing to the small van der Waals radius of oxygen atom and accompanying noncovalent S...O interaction. However, the strong electron donating alkoxy chains on the electron-rich thiophenes lead to elevated FMO levels, which are detrimental to material stability and device performance. Thus, a new design approach is needed to counterbalance the strong electron donating property of alkoxy chains to bring down the FMOs. In this study, we designed and synthesized a new head-to-head linked building block, 4-alkoxy-5-(3-alkylthiophen-2-yl)thiazole (TRTzOR), using an electron-deficient thiazole to replace the electron-rich thiophene. Compared to previously reported 3-alkoxy-3′-alkyl-2,2′-bithiophene (TRTOR), TRTzOR is a weaker electron donor, which considerably lowers FMOs and maintains planar backbone through the noncovalent S...O interaction. The new TRTzOR was copolymerized with benzothiadiazoles with distinct F numbers to yield a series of polymer semiconductors. Compared to TRTOR-based analogous polymers, these TRTzOR-based polymers have broader absorption up to 950 nm with lower-lying FMOs by 0.2-0.3 eV, and blending these polymers with PC 71 BM leads to polymer solar cells (PSCs) with improved open-circuit voltage (V oc ) by ca. 0.1 V and a much smaller energy loss (E loss ) as low as 0.59 eV. These results demonstrate that thiazole substitution is an effective approach to tune FMO levels for realizing higher V oc s in PSCs and the small E loss renders TRTzOR a promising building block for developing high-performance organic semiconductors.
AB - Head-to-head linked bithiophenes with planar backbones hold distinctive advantages for constructing organic semiconductors, such as good solubilizing capability, enabling narrow bandgap, and effective tuning of frontier molecular orbital (FMO) levels using minimal thiophene numbers. In order to realize planar backbone, alkoxy chains are typically installed on thiophene head positions, owing to the small van der Waals radius of oxygen atom and accompanying noncovalent S...O interaction. However, the strong electron donating alkoxy chains on the electron-rich thiophenes lead to elevated FMO levels, which are detrimental to material stability and device performance. Thus, a new design approach is needed to counterbalance the strong electron donating property of alkoxy chains to bring down the FMOs. In this study, we designed and synthesized a new head-to-head linked building block, 4-alkoxy-5-(3-alkylthiophen-2-yl)thiazole (TRTzOR), using an electron-deficient thiazole to replace the electron-rich thiophene. Compared to previously reported 3-alkoxy-3′-alkyl-2,2′-bithiophene (TRTOR), TRTzOR is a weaker electron donor, which considerably lowers FMOs and maintains planar backbone through the noncovalent S...O interaction. The new TRTzOR was copolymerized with benzothiadiazoles with distinct F numbers to yield a series of polymer semiconductors. Compared to TRTOR-based analogous polymers, these TRTzOR-based polymers have broader absorption up to 950 nm with lower-lying FMOs by 0.2-0.3 eV, and blending these polymers with PC 71 BM leads to polymer solar cells (PSCs) with improved open-circuit voltage (V oc ) by ca. 0.1 V and a much smaller energy loss (E loss ) as low as 0.59 eV. These results demonstrate that thiazole substitution is an effective approach to tune FMO levels for realizing higher V oc s in PSCs and the small E loss renders TRTzOR a promising building block for developing high-performance organic semiconductors.
UR - http://www.scopus.com/inward/record.url?scp=85055424889&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85055424889&partnerID=8YFLogxK
U2 - 10.1039/C8RA08360F
DO - 10.1039/C8RA08360F
M3 - Article
AN - SCOPUS:85055424889
VL - 8
SP - 35724
EP - 35734
JO - RSC Advances
JF - RSC Advances
SN - 2046-2069
IS - 62
ER -