Naphthodithiophene–Naphthobisthiadiazole Copolymers for Solar Cells: Alkylation Drives the Polymer Backbone Flat and Promotes Efficiency

Osaka, Itaru; Kakara, Takeshi; Takemura, Noriko; Koganezawa, Tomoyuki; Takimiya, Kazuo

doi:10.1021/ja404064m

Cited by 305 publications

(248 citation statements)

References 34 publications

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“…For OPVs requiring the charge transport normal to substrates, the ideal alignment of crystallites equals to the realization of face-on [55,56] or flat-on orientation [57] of conjugated planes respect to substrates, in other words, to align the efficient intrachain pathways or interchain π-π pathways vertical to substrates. For conjugated polymers adopting preferential edge-on orientation in films, epitaxy crystallization assisted by 1,3,5-trichlorobenzene (TCB) [41,58], mechanic rubbing at a certain temperature [59] and adding additives such as diiodooctane (DIO) [55] are three effective methods to promote face-on orientation in films.…”

Section: Crystallinity and Crystallite Alignmentmentioning

confidence: 99%

Structure and Morphology Control in Thin Films of Conjugated Polymers for an Improved Charge Transport

Wang

et al. 2013

Polymers

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Abstract:The morphological and structural features of the conjugated polymer films play an important role in the charge transport and the final performance of organic optoelectronics devices [such as organic thin-film transistor (OTFT) and organic photovoltaic cell (OPV), etc.] in terms of crystallinity, packing of polymer chains and connection between crystal domains. This review will discuss how the conjugated polymer solidify into, for instance, thin-film structures, and how to control the molecular arrangement of such functional polymer architectures by controlling the polymer chain rigidity, polymer solution aggregation, suitable processing procedures, etc. These basic elements in intrinsic properties and processing strategy described here would be helpful to understand the correlation between morphology and charge transport properties and guide the preparation of efficient functional conjugated polymer films correspondingly.

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Section: Crystallinity and Crystallite Alignmentmentioning

confidence: 99%

Structure and Morphology Control in Thin Films of Conjugated Polymers for an Improved Charge Transport

Wang

et al. 2013

Polymers

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“…[1][2][3][4][5][6][7][8][9] In order to improve the performance of PSCs, the semiconducting polymer must be tuned for its electronic structure, such as the bandgap (E g ), the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels (E HOMO and E LUMO ), since, in principle, small E g offers high short-circuit current density (J SC ) and deep E HOMO offers a high open-circuit voltage (V OC ). Semiconducting polymers consisting of an electron-rich and an electron-poor unit, which is called donor acceptor (D-A) polymers, are particularly attractive, as they offer facile tunability of electronic structures.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of an Alkoxythiazole-thiazolothiazole Semiconducting Polymer for Organic Solar Cells

Saito

Osaka

2017

Electrochemistry

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We report the synthesis and characterization of a new thiazolothiazole (TzTz)-based semiconducting polymer incorporating the alkoxythiazole unit in the polymer backbone (PTzTTz-BOoHD). The introduction of the alkoxythiazole unit in a thiophene-TzTz polymer (PTzBT-BOHD) lowered the LUMO energy level while keeping the HOMO energy level, resulting in a narrower bandgap. The solar cell with PTzTTz-BOoHD showed photoresponse in a wider spectral range (~740 nm) compared to that with PTzBT-BOHD and with a thiophene-TzTz polymer having the alkoxy thiophene unit (PTzBT-BOoHD). Although the fill factor (FF) of the cell based on PTzTTz-BOoHD was lower than the cell based on PTzBT-BOHD and -BOoHD, the maximum PCE of the cell based on PTzTTz-BOoHD resulted in 6.2%, which was comparable to and higher than the cell based on PTzBT-BOHD and -BOoHD, respectively. While PTzTTz-BOoHD showed good crystallinity in the polymer film, it was reduced in the film blended with PC 61 BM, which is likely an origin of the drop of FF. As PTzTTz-BOoHD has more suitable electronic structures for solar cells such as a deep HOMO level and a narrow bandgap, compared to the other two polymers, we expect that PTzTTz-BOoHD would demonstrate higher PCE by further device optimization.

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“…Power conversion efficiency (PCE) which is higher than 9% has been reached recently [2][3][4][5][6][7][8][9][10][11][12][13][14]. Currently, BHJ OSCs are based on two types of donor materials, conjugated polymers and small molecules [15,16].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and photovoltaic properties of new small molecules with rhodanine derivative as the end-capped blocks

Zhou

Xiao

Liu

et al. 2015

Organic Electronics

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a b s t r a c tTwo new acceptor-donor-acceptor (A-D-A) type small molecules DCAO3TIDT and DCNR3TIDT, with 4,4,9,9-tetrakis(4-(dodecyloxy)phenyl)-4,9-dihydro-s-indaceno-[1,2-b:5,6-b 0 ]dithiophene (IDT) as the core group and 2-ethylhexyl cyanoacetate (CAO) and 2-(1,1-dicyanomethylene)-3-octyl rhodanine (CNR) as different end-capped blocks, have been designed and synthesized. Both of them have been employed as donor for solutionprocessed bulk hetero-junction (BHJ) organic solar cells (OSCs). The two compounds showed deep highest occupied molecular orbital (HOMO) energy levels ($À5.30 eV) and strong absorption. The DCAO3TIDT and DCNR3TIDT with PC 71 BM as acceptor based BHJ solar cell devices showed short circuit current density (J sc ) of 6.93 mA/cm 2 and 8.59 mA/ cm 2 , power conversion efficiency (PCE) of 3.34% and 4.27%, respectively, and with almost same open-circuit voltage ($0.93 V), under the illumination of AM 1.5 G, 100 mW/cm 2 . The high J sc for DCNR3TIDT could result from its wider and red-shifted absorption than that of DCAO3TIDT, which was probably induced by the end-capped block rhodanine derivative. The results demonstrate that the end group would be taken into full account when designing new solution-processed small molecules, which is an important factor to determine their photovoltaic properties.

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Naphthodithiophene–Naphthobisthiadiazole Copolymers for Solar Cells: Alkylation Drives the Polymer Backbone Flat and Promotes Efficiency

Cited by 305 publications

References 34 publications

Structure and Morphology Control in Thin Films of Conjugated Polymers for an Improved Charge Transport

Structure and Morphology Control in Thin Films of Conjugated Polymers for an Improved Charge Transport

Synthesis and Characterization of an Alkoxythiazole-thiazolothiazole Semiconducting Polymer for Organic Solar Cells

Synthesis and photovoltaic properties of new small molecules with rhodanine derivative as the end-capped blocks

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