- Highly crystalline new benzodithiophene-benzothiadiazole copolymer for efficient ternary polymer solar cells with an energy conversion efficiency of over 10%
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A new alternating polymer P(BDTSi-DFBT), poly(4,8-bis(triisopropylsilylethynyl)-benzo[1,2-b:4,5-b′]dithiophene-alt-5,6-difluoro-4,7-bis(4-octylthiophen-2-yl)benzo[c][1,2,5]thiadiazole), was prepared via Stille polymerization. The determined absorption maximum and optical band-gap (Eg) of P(BDTSi-DFBT) were 590 nm and 1.74 eV, respectively. The calculated highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of P(BDTSi-DFBT) were -5.45 eV and -3.71 eV, respectively. The X-ray diffraction (XRD) analysis confirmed that P(BDTSi-DFBT) is a crystalline polymer. The binary-polymer solar cells, ITO/PEDOT:PSS/P(BDTSi-DFBT):PC70BM (1:1.5 wt%) + 3 vol% DIO/Al, made from P(BDTSi-DFBT) gave a power conversion efficiency (PCE) of 5.02% with an open-circuit voltage (Voc) of 0.81 V, a short-circuit current (Jsc) of 11.68 mA cm-2, and a fill factor (FF) of 53%. Conversely, the ternary-polymer solar cells, ITO/PEDOT:PSS/PTB7-Th:P(BDTSi-DFBT):PC70BM (0.8:0.2:1.5 wt%) + 3 vol% DIO/Al, made with a synthesized medium band-gap P(BDTSi-DFBT) and low band-gap PTB7-Th, offered a maximum PCE of 10.05%, with a Voc of 0.79 V, a Jsc of 17.92 mA cm-2, and a FF of 71%.
- Tamilavan, Vellaiappillai,Liu, Yanliang,Lee, Jihoon,Jung, Yun Kyung,Son, Semo,Jeong, Junghyun,Park, Sung Heum
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- Novel photovoltaic donor 1-acceptor-donor 2-acceptor terpolymers with tunable energy levels based on a difluorinated benzothiadiazole acceptor
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A novel donor 1-acceptor-donor 2-acceptor (D1-A-D2-A) type terpolymer PBDT-DTffBT-F-DTffBT was prepared to further tune the energy levels of donor-acceptor (D-A) type copolymer PBDT-DTffBT and PF-DTffBT, and the corresponding optoelectronic properties have been investigated. By incorporating the weak donor fluorene unit into the backbone of PBDT-DTffBT, the PBDT-DTffBT-F-DTffBT exhibits a lower HOMO level and higher LUMO level compared with PBDT-DTffBT as expected. The polymer solar cell (PSC) based on PBDT-DTffBT-F-DTffBT affords the improved PCE with a higher Voc of 0.853 V compared to the D-A copolymer PBDT-DTffBT and PF-DTffBT. Therefore, through carefully choosing the suitable donor group, the class of D1-A-D2-A type copolymers would be a promising organic semiconducting material.
- Deng, Zhiqiang,Wu, Feiyan,Chen, Lie,Chen, Yiwang
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p. 12087 - 12093
(2015/02/19)
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- 5,6-Difluorobenzothiadiazole and silafluorene based conjugated polymers for organic photovoltaic cells
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To achieve 5,6-difluorobenzothiadiazole and 2,7-linked silafluorene based soluble conjugated polymers, flexible side chains were attached at different positions of the conjugated polymers. Three soluble polymers PSiF-D(OT)DFBT, PSiF-TTDFBT, and PDOSiF-DTDFBT were prepared and used as donor materials for polymer solar cells. PSiF-D(OT)DFBT exhibits a band gap of 2.06 eV with a deep HOMO of -5.64 eV. PSiF-TTDFBT shows a band gap of 1.75 eV with the HOMO of -5.23 eV. PDOSiF-DTDFBT is of a band gap of 1.86 eV with the HOMO level of -5.37 eV. Among these three polymers, PDOSiF-DTDFBT shows the highest field effect transistor (FET) hole mobility up to 3.31 × 10-2 cm2 V-1 s-1, PDOSiF-DTDFBT:PC71BM blend films show the highest SCLC mobility up to 5.10 × 10-4 cm2 V-1 s-1, and polymer solar cells (PSCs) with the blend of PDOSiF-DTDFBT:PC71BM (1:1, by weight) as the active layer gave a power conversion efficiency (PCE) of 4.03% with an open circuit voltage (V oc) of 0.73 V, a short circuit current (Jsc) of 8.55 mA cm-2, and a fill factor (FF) of 0.65. Our studies also reveal the structure-property relationship of 2,7-linked silafluorene and 5,6-difluorobenzothiadiazole based conjugated polymers.
- Li, Guangwu,Kang, Chong,Gong, Xue,Zhang, Jicheng,Li, Weiwei,Li, Cuihong,Dong, Huanli,Hu, Wenping,Bo, Zhishan
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p. 5116 - 5123
(2014/07/07)
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- Synthesis and applications of difluorobenzothiadiazole based conjugated polymers for organic photovoltaics
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A new electron deficient building block, difluorobenzothiadiazole (FBT) was designed and synthesized for the first time. Two low band gap polymers containing this unit or benzothiadiazole (BT) and an electron rich unit, benzo[1,2-b:4,5-b′]dithiophene (BDT
- Li, Zhao,Lu, Jianping,Tse, Shing-Chi,Zhou, Jiayun,Du, Xiaomei,Tao, Ye,Ding, Jianfu
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experimental part
p. 3226 - 3233
(2011/10/04)
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- FLUORINATED MONOMERS, OLIGOMERS AND POLYMERS FOR USE IN ORGANIC ELECTRONIC DEVICES
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Compounds of Formula (I): (formula (I)) where: X1 and X2 are the same or different and each is independently Cl, Br, I, a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group; and, Y is O, S, Se,
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Page/Page column 9-10
(2011/06/19)
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