Record High Hole Mobility in Polymer Semiconductors via Side-Chain Engineering

Through manipulation of the solubilizing side chains, we were able to dramatically improve the molecular weight(Mw)of 4,8-dialkoxybenzo[1,2-b:4,5-b′]dithiophene (BDT)/2,1,3-benzothiadiazole (BT) copolymers. When dodecyl side chains (P1) are employed at the 4- and 8-positions of the BDT unit, we obtain a chloroform-soluble copolymer fraction withMwof 6.3 kg/mol. Surprisingly, by moving to the commonly employed 2-ethylhexyl branch (P2),Mwdecreases to 3.4 kg/mol. This is despite numerous reports that this side chain increases solubility andMw. By moving the ethyl branch in one position relative to the polymer backbone (1-ethylhexyl,P3),Mwis dramatically increased to 68.8 kg/mol. As a result of thisMwincrease, the shape of the absorption profile is dramatically altered, withλmax= 637 nm compared with 598 nm forP1and 579 nm forP2. The hole mobility as determined by thin film transistor (TFT) measurements is improved from~1×10−6 cm2/Vs forP1andP2to7×10−4 cm2/Vs forP3, while solar cell power conversion efficiency in increased to2.91%forP3relative to0.31%and0.19%forP1andP2, respectively.

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Intrinsically Stretchable n-Type Polymer Semiconductors through Side Chain Engineering

Macromolecules ◽

10.1021/acs.macromol.1c00936 ◽

2021 ◽

Author(s):

Yafei Ding ◽

Ye Yuan ◽

Ning Wu ◽

Xiaohong Wang ◽

Guobing Zhang ◽

...

Keyword(s):

Side Chain ◽

Polymer Semiconductors

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Influence of side chain length and bifurcation point on the crystalline structure and charge transport of diketopyrrolopyrrole-quaterthiophene copolymers (PDQTs)

Journal of Materials Chemistry C ◽

10.1039/c3tc32219j ◽

2014 ◽

Vol 2 (12) ◽

pp. 2183-2190 ◽

Cited By ~ 43

Author(s):

Shaoyun Chen ◽

Bin Sun ◽

Wei Hong ◽

Hany Aziz ◽

Yuezhong Meng ◽

...

Keyword(s):

Charge Transport ◽

Chain Length ◽

Crystalline Structure ◽

Bifurcation Point ◽

Hole Mobility ◽

Side Chain ◽

Polymer Backbone ◽

Side Chain Length

Increasing the side chain length and positioning the bifurcation point away from the polymer backbone improve the hole mobility of a DPP polymer to 6.90 cm2 V−1 s−1.

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Small Molecule with Extended Alkyl Side Substituents for Organic Solar Cells

MRS Advances ◽

10.1557/adv.2016.668 ◽

2016 ◽

Vol 2 (42) ◽

pp. 2253-2259 ◽

Cited By ~ 1

Author(s):

Chenyu Zheng ◽

Ishita Jalan ◽

Jeremy A. Cody ◽

Christopher J. Collison

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Small Molecules ◽

Organic Solar Cells ◽

Hole Mobility ◽

Superior Performance ◽

Side Chain ◽

Alkyl Side Chain ◽

Transmission Electron ◽

Absorbance Spectra

ABSTRACTIn this work, we have investigated two aniline based squaraine molecules, DBSQ(OH)2 and DHSQ(OH)2, for their potential application in organic photovoltaics. These two squaraine molecules are only different in side chain length (i.e. butyl vs. hexyl). Yet, their solar cell properties are drastically different (PCE = 3.6% vs. 1.9%). We have further investigated the reason behind the superior performance of DBSQ(OH)2 in absorbance spectra, hole mobility characterization and transmission electron microscopy. The results show that DBSQ(OH)2 has a higher hole mobility (5.1×10-4 cm2/V•s vs. 1.4×10-4 cm2/V•s) and is able to mix well with the fullerene acceptor compared to DHSQ(OH)2. Our work shows clearly that the long solubilizing alkyl side chain might be detrimental for OPV performance and that shorter side chains with enough solubility have great value when designing small molecules.

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Naphthodithiophene-Diketopyrrolopyrrole Small Molecule Donors for Efficient Solution-Processed Solar Cells

MRS Proceedings ◽

10.1557/opl.2012.459 ◽

2012 ◽

Vol 1390 ◽

Author(s):

Stephen Loser ◽

Carson J. Bruns ◽

Hiroyuki Miyauchi ◽

Rocío Ponce Ortiz ◽

Antonio Facchetti ◽

...

Keyword(s):

Solar Cells ◽

Small Molecule ◽

Electron Acceptor ◽

Efficient Solution ◽

Power Conversion ◽

Hole Mobility ◽

Side Chain ◽

Device Performance ◽

Visible Absorption ◽

Selection Of

ABSTRACTWe report the synthesis, characterization, and implementation of various naphtho[2,3- b:6,7-b’]dithiophene (NDT)-based donor molecules for organic photovoltaics (OPVs) When NDT(TDPP)2 (TDPP = thiophene-capped diketopyrrolopyrrole) contains all branched 2- ethylhexyl chains and is combined with the electron acceptor PC61BM, a power conversion efficiency (PCE) of 4.06±0.6% is achieved. This respectable PCE is attributed to the broad, high oscillator strength visible absorption, the ordered molecular packing, and a high hole mobility of 0.04 cm2·V-1·s-1. We find utilizing linear C-12 side chains on either the TDPP or NDT framework dramatically increases the d-spacing, which directly correlates with inferior OPV device performance. This leads to the conclusion that the selection of an appropriate side chain plays a key role in determining OPV device performance of a small molecule donor.

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Effect of the alkyl spacer length on the electrical performance of diketopyrrolopyrrole-thiophene vinylene thiophene polymer semiconductors

Journal of Materials Chemistry C ◽

10.1039/c5tc02565f ◽

2015 ◽

Vol 3 (44) ◽

pp. 11697-11704 ◽

Cited By ~ 40

Author(s):

Hojeong Yu ◽

Kwang Hun Park ◽

Inho Song ◽

Myeong-Jong Kim ◽

Yun-Hi Kim ◽

...

Keyword(s):

Electrical Performance ◽

Side Chain ◽

Device Performance ◽

Spacer Length ◽

Polymer Semiconductors

Systematic side-chain engineering through adjustment of spacer groups in diketopyrrolopyrrole-thiophene vinylene thiophene (DPP-TVT) polymers reveals odd–even dependence of device performance.

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Light-Emitting and Hole-Transporting Polymers for LEDs

MRS Proceedings ◽

10.1557/proc-488-21 ◽

1997 ◽

Vol 488 ◽

Author(s):

Toshihiro Ohnishi ◽

Shuji Doi ◽

Masato Ueda ◽

Fumi Yamaguchi ◽

Takanobu Noguchi

Keyword(s):

High Efficiency ◽

Hole Mobility ◽

Hole Injection ◽

Side Chain ◽

High Luminance ◽

Strong Fluorescence ◽

Light Emitting ◽

Hole Transporting ◽

Hole Transporting Material ◽

Injection Barrier

AbstractVarious copolymers of arylene vinylenes, having strong fluorescence, showed predominantly the emission in the multi-layer device using an electron-transporting material(ETM) such as tris(8-quinolinolato)aluminum(Alq3). The emission from Alq3 was suppressed due to the high hole-injection barrier from the copolymers to ETM in spite of low or no barriers of electron injection from ETM to the copolymers. We have successfully prepared highly hole-transporting polysilane having a triphenylamine group as a side chain(TPA-PS). The hole mobility as high as 10 cm3cm2/Vs is attributable to the intermolecular hopping process facilitated by the interaction between the polysilane backbone and the triphenylamine group. The polysilane is effectively used as a hole transporting material. The bilayer LED device consisting of TPA-PS and Akb3 showed high luminance (2000cd/m2) and high efficiency (4cd/A).

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Intrinsically stretchable polymer semiconductors: molecular design, processing and device applications

Journal of Materials Chemistry C ◽

10.1039/d0tc06059c ◽

2021 ◽

Author(s):

Hsin-Chiao Tien ◽

Yen-Wen Huang ◽

Yu-Cheng Chiu ◽

Yu-Hsuan Cheng ◽

Chu-Chen Chueh ◽

...

Keyword(s):

Molecular Design ◽

Side Chain ◽

Next Generation ◽

Polymer Blending ◽

Polymer Semiconductors ◽

Device Applications

This review surveys the current developments of intrinsic stretchable polymer semiconductors, including backbone and side-chain engineering, polymer blending, fabrication processes and their next-generation biomimicking applications.

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