Synthesis and photovoltaic properties of cyclopentadithiophene-based low-bandgap copolymers that contain electron-withdrawing thiazole derivatives

Hwan Jung, Jinyoung Yu, Eunjae Jeong, Jinseck Kim, Sooncheol Kwon, Hoyoul Kong, Kwanghee Lee, Han Young Woo, Hong Ku Shim

Research output: Contribution to journalArticle

97 Citations (Scopus)

Abstract

We have synthesized four types of cyclopentadithiophene (CDT)based low-bandgap copolymers, poly[{4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1 -b :3,4-b']dithiophene-2,6-diy1}-alt(2,2'-bithiazole-5,5'-diy1)] (PehCDTBT), poly[(4,4-dioctyl-4H-cyclopenta[2,1-b:3,4-b']dithiophene-2,6-diyl)-alt(2, 2'-bithiazole-5,5'-diyl)] (PocCDTBT), poly[{4,4-bis(2-ethylhexyl)-4H- cyclopenta[2,1-b:3,4-b)']dithiophene-2,6diyl}-alt-{2,5-di(thiophen-2-y1) thiazolo[5,4-d]thiazole-5,5'-diy1}] (PehCDTTZ), and poly[(4,4-dioctyl-4H- cyclopenta[2,1-b:3,4-b']dithiophene-2,6diyl)-alt-{2,5-di(thiophen-2-y1) thiazolo[5,4-d]thiazole-5,5'-diy1}] (PocCDTTZ), for use in photovoltaic applications. The intramolecular charge-transfer interaction between the electronsufficient CDT unit and electron-deficient bithiazole (BT) or thiazolothiazole (TZ) units in the polymeric backbone induced a low bandgap and broad absorption that covered 300 nm to 700800 nm. The optical bandgap was measured to be around 1.9 eV for PehCDT-BT and PocCDT-BT, and around 1.8 eV for PehCDT-TZ and PocCDT-TZ. Gel permeation chromatography showed that number-average molecular weights ranged from 8000 to 14000 g mol- 1 . Field-effect mobility measurements showed hole mobility of 10 6 -10- 4 Cm 2 V- 1 s- 1 for the copolymers. The film morphology of the bulk heteroj unction mixtures with [6,6]phenyl-C 61 -butyric acid methyl ester (PCBM) was also examined by atomic force microscopy before and after heat treatment. When the polymers were blended with PCBM, PehCDT-TZ exhibited the best performance with an open circuit voltage of 0.69 V, short-circuit current of 7.14 mA cm- 2 , and power conversion efficiency of 2.23% under air mass (AM) 1.5 global (1.5 G) illumination conditions (100 mWcm- 2 ).

Original languageEnglish
Pages (from-to)3743-3752
Number of pages10
JournalChemistry - A European Journal
Volume16
Issue number12
DOIs
Publication statusPublished - 2010 Mar 22
Externally publishedYes

Fingerprint

Thiazoles
Butyric acid
Butyric Acid
Esters
Energy gap
Copolymers
Electrons
Derivatives
Hole mobility
Atomic Force Microscopy
Optical band gaps
Gel permeation chromatography
Open circuit voltage
Lighting
Short circuit currents
Conversion efficiency
Gel Chromatography
Charge transfer
Atomic force microscopy
Polymers

Keywords

  • Charge transfer
  • Photovoltaic effects
  • Pi interactions
  • Polymerization • thin layers

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

Cite this

Synthesis and photovoltaic properties of cyclopentadithiophene-based low-bandgap copolymers that contain electron-withdrawing thiazole derivatives. / Jung, Hwan; Yu, Jinyoung; Jeong, Eunjae; Kim, Jinseck; Kwon, Sooncheol; Kong, Hoyoul; Lee, Kwanghee; Woo, Han Young; Shim, Hong Ku.

In: Chemistry - A European Journal, Vol. 16, No. 12, 22.03.2010, p. 3743-3752.

Research output: Contribution to journalArticle

Jung, Hwan ; Yu, Jinyoung ; Jeong, Eunjae ; Kim, Jinseck ; Kwon, Sooncheol ; Kong, Hoyoul ; Lee, Kwanghee ; Woo, Han Young ; Shim, Hong Ku. / Synthesis and photovoltaic properties of cyclopentadithiophene-based low-bandgap copolymers that contain electron-withdrawing thiazole derivatives. In: Chemistry - A European Journal. 2010 ; Vol. 16, No. 12. pp. 3743-3752.
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abstract = "We have synthesized four types of cyclopentadithiophene (CDT)based low-bandgap copolymers, poly[{4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1 -b :3,4-b']dithiophene-2,6-diy1}-alt(2,2'-bithiazole-5,5'-diy1)] (PehCDTBT), poly[(4,4-dioctyl-4H-cyclopenta[2,1-b:3,4-b']dithiophene-2,6-diyl)-alt(2, 2'-bithiazole-5,5'-diyl)] (PocCDTBT), poly[{4,4-bis(2-ethylhexyl)-4H- cyclopenta[2,1-b:3,4-b)']dithiophene-2,6diyl}-alt-{2,5-di(thiophen-2-y1) thiazolo[5,4-d]thiazole-5,5'-diy1}] (PehCDTTZ), and poly[(4,4-dioctyl-4H- cyclopenta[2,1-b:3,4-b']dithiophene-2,6diyl)-alt-{2,5-di(thiophen-2-y1) thiazolo[5,4-d]thiazole-5,5'-diy1}] (PocCDTTZ), for use in photovoltaic applications. The intramolecular charge-transfer interaction between the electronsufficient CDT unit and electron-deficient bithiazole (BT) or thiazolothiazole (TZ) units in the polymeric backbone induced a low bandgap and broad absorption that covered 300 nm to 700800 nm. The optical bandgap was measured to be around 1.9 eV for PehCDT-BT and PocCDT-BT, and around 1.8 eV for PehCDT-TZ and PocCDT-TZ. Gel permeation chromatography showed that number-average molecular weights ranged from 8000 to 14000 g mol- 1 . Field-effect mobility measurements showed hole mobility of 10 6 -10- 4 Cm 2 V- 1 s- 1 for the copolymers. The film morphology of the bulk heteroj unction mixtures with [6,6]phenyl-C 61 -butyric acid methyl ester (PCBM) was also examined by atomic force microscopy before and after heat treatment. When the polymers were blended with PCBM, PehCDT-TZ exhibited the best performance with an open circuit voltage of 0.69 V, short-circuit current of 7.14 mA cm- 2 , and power conversion efficiency of 2.23{\%} under air mass (AM) 1.5 global (1.5 G) illumination conditions (100 mWcm- 2 ).",
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author = "Hwan Jung and Jinyoung Yu and Eunjae Jeong and Jinseck Kim and Sooncheol Kwon and Hoyoul Kong and Kwanghee Lee and Woo, {Han Young} and Shim, {Hong Ku}",
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TY - JOUR

T1 - Synthesis and photovoltaic properties of cyclopentadithiophene-based low-bandgap copolymers that contain electron-withdrawing thiazole derivatives

AU - Jung, Hwan

AU - Yu, Jinyoung

AU - Jeong, Eunjae

AU - Kim, Jinseck

AU - Kwon, Sooncheol

AU - Kong, Hoyoul

AU - Lee, Kwanghee

AU - Woo, Han Young

AU - Shim, Hong Ku

PY - 2010/3/22

Y1 - 2010/3/22

N2 - We have synthesized four types of cyclopentadithiophene (CDT)based low-bandgap copolymers, poly[{4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1 -b :3,4-b']dithiophene-2,6-diy1}-alt(2,2'-bithiazole-5,5'-diy1)] (PehCDTBT), poly[(4,4-dioctyl-4H-cyclopenta[2,1-b:3,4-b']dithiophene-2,6-diyl)-alt(2, 2'-bithiazole-5,5'-diyl)] (PocCDTBT), poly[{4,4-bis(2-ethylhexyl)-4H- cyclopenta[2,1-b:3,4-b)']dithiophene-2,6diyl}-alt-{2,5-di(thiophen-2-y1) thiazolo[5,4-d]thiazole-5,5'-diy1}] (PehCDTTZ), and poly[(4,4-dioctyl-4H- cyclopenta[2,1-b:3,4-b']dithiophene-2,6diyl)-alt-{2,5-di(thiophen-2-y1) thiazolo[5,4-d]thiazole-5,5'-diy1}] (PocCDTTZ), for use in photovoltaic applications. The intramolecular charge-transfer interaction between the electronsufficient CDT unit and electron-deficient bithiazole (BT) or thiazolothiazole (TZ) units in the polymeric backbone induced a low bandgap and broad absorption that covered 300 nm to 700800 nm. The optical bandgap was measured to be around 1.9 eV for PehCDT-BT and PocCDT-BT, and around 1.8 eV for PehCDT-TZ and PocCDT-TZ. Gel permeation chromatography showed that number-average molecular weights ranged from 8000 to 14000 g mol- 1 . Field-effect mobility measurements showed hole mobility of 10 6 -10- 4 Cm 2 V- 1 s- 1 for the copolymers. The film morphology of the bulk heteroj unction mixtures with [6,6]phenyl-C 61 -butyric acid methyl ester (PCBM) was also examined by atomic force microscopy before and after heat treatment. When the polymers were blended with PCBM, PehCDT-TZ exhibited the best performance with an open circuit voltage of 0.69 V, short-circuit current of 7.14 mA cm- 2 , and power conversion efficiency of 2.23% under air mass (AM) 1.5 global (1.5 G) illumination conditions (100 mWcm- 2 ).

AB - We have synthesized four types of cyclopentadithiophene (CDT)based low-bandgap copolymers, poly[{4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1 -b :3,4-b']dithiophene-2,6-diy1}-alt(2,2'-bithiazole-5,5'-diy1)] (PehCDTBT), poly[(4,4-dioctyl-4H-cyclopenta[2,1-b:3,4-b']dithiophene-2,6-diyl)-alt(2, 2'-bithiazole-5,5'-diyl)] (PocCDTBT), poly[{4,4-bis(2-ethylhexyl)-4H- cyclopenta[2,1-b:3,4-b)']dithiophene-2,6diyl}-alt-{2,5-di(thiophen-2-y1) thiazolo[5,4-d]thiazole-5,5'-diy1}] (PehCDTTZ), and poly[(4,4-dioctyl-4H- cyclopenta[2,1-b:3,4-b']dithiophene-2,6diyl)-alt-{2,5-di(thiophen-2-y1) thiazolo[5,4-d]thiazole-5,5'-diy1}] (PocCDTTZ), for use in photovoltaic applications. The intramolecular charge-transfer interaction between the electronsufficient CDT unit and electron-deficient bithiazole (BT) or thiazolothiazole (TZ) units in the polymeric backbone induced a low bandgap and broad absorption that covered 300 nm to 700800 nm. The optical bandgap was measured to be around 1.9 eV for PehCDT-BT and PocCDT-BT, and around 1.8 eV for PehCDT-TZ and PocCDT-TZ. Gel permeation chromatography showed that number-average molecular weights ranged from 8000 to 14000 g mol- 1 . Field-effect mobility measurements showed hole mobility of 10 6 -10- 4 Cm 2 V- 1 s- 1 for the copolymers. The film morphology of the bulk heteroj unction mixtures with [6,6]phenyl-C 61 -butyric acid methyl ester (PCBM) was also examined by atomic force microscopy before and after heat treatment. When the polymers were blended with PCBM, PehCDT-TZ exhibited the best performance with an open circuit voltage of 0.69 V, short-circuit current of 7.14 mA cm- 2 , and power conversion efficiency of 2.23% under air mass (AM) 1.5 global (1.5 G) illumination conditions (100 mWcm- 2 ).

KW - Charge transfer

KW - Photovoltaic effects

KW - Pi interactions

KW - Polymerization • thin layers

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