Xike Gao

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Organization: Shanghai Institute of Organic Chemistry

Department: Laboratory of Materials Science

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Organic Chemistry

Organic Semiconductor

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References

Application of direct (hetero)arylation in constructing conjugated small molecules and polymers for organic optoelectronic devices

Co-reporter:Wenting Wu, Hanshen Xin, Congwu Ge, Xike Gao

Tetrahedron Letters 2017 Volume 58(Issue 3) pp:175-184

Publication Date(Web):18 January 2017

DOI:10.1016/j.tetlet.2016.11.126

•Direct (hetero)arylation is a sustainable, atom-economic and environmentally benign synthetic protocol.•Recent advances in direct arylation for preparing high performance conjugated small molecules and polymers.•Some valuable insights in direct arylation for synthesizing organic optoelectronic materials are given.Direct (hetero)arylation, as a sustainable, atom-economic and environmentally benign synthetic protocol compared to conventional coupling techniques, has been extensively applied to the sustainable preparation of π-conjugated materials for organic optoelectronic devices. In this review, we will highlight recent advances made in direct arylation for conjugated small molecules and polymers toward high performance organic optoelectronic devices. Some important insights in direct arylation for synthesizing organic optoelectronic materials are given, together with the challenges and outlook in this significant and hot research field.Figure optionsDownload full-size imageDownload high-quality image (72 K)Download as PowerPoint slide

Synthesis of largely π-extended naphthalenediimides via C–H activation towards highly soluble and narrow band-gap organic optoelectronic materials

Co-reporter:Wenting Wu;Jing Li;Zheng Zhao;Xiaodi Yang

Organic Chemistry Frontiers 2017 vol. 4(Issue 5) pp:823-827

Publication Date(Web):2017/05/03

DOI:10.1039/C7QO00061H

Atom-economic coupling reactions based on C–H activation are generally used to synthesize small conjugated systems, but their applications in constructing largely π-conjugated systems have been rarely reported. Herein, we report the preparation of largely π-extended naphthalenediimides (4a–c, with molecular weights of up to 2800) by using efficient palladium-catalyzed C–H/C–H homocouplings, with the yields of up to 94%. The physicochemical properties of 4a–c were studied and they exhibited excellent solubility, thermal stability, quasi-reversible reduction processes, broad and long-wavelength optical absorptions with thin-film optical gaps <1.4 eV and fine-tuned deep LUMO energies (<−4.2 eV), which together with ambient stable electron-transporting behaviors demonstrate their promising applications in optoelectronic devices.

A Class of Electron-Transporting Vinylogous Tetrathiafulvalenes Constructed by the Dimerization of Core-Expanded Naphthalenediimides

Co-reporter:Yunbin Hu, Zhongli Wang, Xu Zhang, Xiaodi Yang, Congwu Ge, Lina Fu, and Xike Gao

Organic Letters 2017 Volume 19(Issue 3) pp:

Publication Date(Web):January 11, 2017

DOI:10.1021/acs.orglett.6b03614

The combination of the (1,3-dithiol-2-ylidene)malononitrile (DTYM) and/or (1,3-dithiol-2-ylidene)acetonitrile (DTYA) moieties with naphthalenediimide (NDI) core affords two singly linked NDI-based dimers, (DTYM-NDI-DTYA)2 (D1) and (NDI-DTYA)2 (D2), which both contain a dicyano-substituted vinylogous tetrathiafulvalene (TTF) unit. The synthesis, thermal/optical/electrochemical properties of D1 and D2, and their primary applications in n-channel organic thin film transistors are studied. The results demonstrate that these NDI-fused vinylogous TTFs are excellent electron acceptors, and their further applications are promising.

Dithieno[3,2-a:3′,2′-j][5,6,11,12]chrysene diimides and their molecular energy level regulation

Co-reporter:Xueqian Zhao;Congwu Ge;Xiaodi Yang

Materials Chemistry Frontiers 2017 vol. 1(Issue 8) pp:1635-1640

Publication Date(Web):2017/07/27

DOI:10.1039/C7QM00030H

Dithieno[3,2-a:3′,2′-j][5,6,11,12]chrysene diimides (DTCDIs), a new class of organic dyes, with a twisted molecular backbone were designed and synthesized. The optical and electrochemical properties, charge transport behaviors and the single crystal structure were investigated. The cyanation of the DTCDI backbone was carried out to fine-tune the molecular energy levels. The addition of two cyano groups to the DTCDI backbone reduced the HOMO and LUMO energy levels by 0.35 and 0.30 eV, respectively. The energy levels could be further reduced with the addition of two more cyano groups leading to 0.32 and 0.22 eV reductions in HOMO and LUMO energy levels and stabilization of the energy levels. A tetracyano-substituted DTCDI derivative showed an electron mobility of 0.25 cm2 V−1 s−1 and a current on/off ratio of 106 in its organic thin film transistors.

Incorporation of benzothiadiazole into the backbone of 1,2,5,6-naphthalenediimide based copolymers, enabling much improved film crystallinity and charge carrier mobility

Co-reporter:Zheng Zhao, Zhongli Wang, Congwu Ge, Xu Zhang, Xiaodi Yang and Xike Gao

Polymer Chemistry 2016 vol. 7(Issue 3) pp:573-579

Publication Date(Web):13 Nov 2015

DOI:10.1039/C5PY01709B

By incorporating benzothiadiazole units into the main chain of 1,2,5,6-naphthalenediimide (iso-NDI) and thiophene based copolymers, we report herein a new high performance donor–acceptor (D–A) polymer, P(iso-NDI-TBT), with much improved film crystallinity and charge carrier mobility. The optical, electrochemical, and charge transport properties as well as the photovoltaic performance were investigated. Bottom-gate bottom-contact organic field-effect transistors (OFETs) based on the thin films of P(iso-NDI-TBT) show a high hole mobility of up to 0.82 cm2 V−1 s−1, which is a record value for the 1,2,5,6-NDI based polymers. In addition, the photovoltaic performance of P(iso-NDI-TBT) was also studied, affording a power conversion efficiency (PCE) of 1.5% with a high open-circuit voltage (Voc) of 0.9 V. Our work provides important clues for designing high performance D–A polymeric semiconductors and also demonstrates that 1,2,5,6-NDIs are promising building blocks for constructing new polymer semiconductors.

Fine-tuning the molecular energy levels by incorporating thiophene units onto the π-backbone of core-expanded naphthalene diimides

Co-reporter:Dong Lu, Xiao-Chun Yang, Bing Leng, Xiao-Di Yang, Cong-Wu Ge, Xue-Shun Jia, Xi-Ke Gao

Chinese Chemical Letters 2016 Volume 27(Issue 7) pp:1022-1026

Publication Date(Web):July 2016

DOI:10.1016/j.cclet.2016.05.003

A series of core-expanded naphthalene diimides (NDI-DTYM) and thiophene-based derivatives (1a–c) were designed and synthesized to investigate the relationship between molecular structures and the highest occupied molecular orbital (HOMO) energy levels but has little impact on the lowest unoccupied molecular orbital (LUMO) energy levels. The results demonstrated that increasing the number of thiophene units can gradually elevate the HOMO energy levels but had little impact on the LUMO energy levels. The n-channel organic field-effect transistors (OFETs) based on 1b and 1c have demonstrated that these almost unchanged LUMO energy levels are proper to transport electrons.A series of organic semiconductors based on NDI-DTYM and thiophene were designed to investigate the relationship between molecular structure and the molecular frontier orbital energy levels. The results demonstrated that increasing the number of thiophene units leads to the gradually elevated HOMO energy levels but the almost unchanged LUMO levels.

Photoresponsive organic field-effect transistors involving photochromic molecules

Co-reporter:Li-Na Fu, Bing Leng, Yong-Sheng Li, Xi-Ke Gao

Chinese Chemical Letters 2016 Volume 27(Issue 8) pp:1319-1329

Publication Date(Web):August 2016

DOI:10.1016/j.cclet.2016.06.045

In recent years, organic field-effect transistors (OFETs) with high performance and novel multi-functionalities have attracted considerable attention. Meanwhile, featured with reversible photo-isomerization and the corresponding variation in color, chemical/physical properties, photochromic molecules have been applied in sensors, photo-switches and memories. Incorporation of photochromic molecules to blend in the device functional layers or to modify the interfaces of OFETs is common way to build photo-transistors. In this review, we focus on the recent advantages on the study of photoresponsive transistors involving one of three typical photochromic compounds spiropyran, diarylethene and azobenzene. Three main strategies are demonstrated in detail. Firstly, photochromic molecules are doped in active layers or combined with semiconductor structure thus forming photo-reversible active layers. Secondly, the modification of dielectric layer/active layer interface is mainly carried out by bilayer dielectric. Thirdly, the photo-isomerization of self-assembled monolayer (SAM) on the electrode/active layer interface can reversibly modulate the work functions and charge injection barrier, result in bifunctional OFETs. All in all, the combination of photochromic molecules and OFETs is an efficient way for the fabrication of organic photoelectric devices. Photoresponsive transistors consisted of photochromic molecules are potential candidate for real applications in the future.Recent advances in photoresponsive organic field-effect transistors by using three classes of photochromic molecules (spiropyran, diarylethene, and azobenzene) were summarized and highlighted to give some valuable insights.

n-Channel Organic Transistors Processed from Halogen-Free Solvents: Solvent Effect on Thin-Film Morphology and Charge Transport

Co-reporter:Simin Gao;Yonghui Hu;Zhiming Duan

Chinese Journal of Chemistry 2016 Volume 34( Issue 7) pp:689-695

Publication Date(Web):

DOI:10.1002/cjoc.201600131

Abstract

Non-chlorinated solvents are highly preferable for organic electronic processing due to their environmentally friendly characteristics. Four different halogen-free solvents, tetrafuran, toluene, meta-xylene and 1,2,4-trimethylbenzene, were selected to fabricate n-channel organic thin film transistors (OTFTs) based on 3-hexylundecyl substituted naphthalene diimides fused with (1,3-dithiol-2-ylidene)malononitrile groups (NDI3HU-DTYM2). The OTFTs based on NDI3HU-DTYM2 showed electron mobility of up to 1.37 cm²·V⁻¹·s⁻¹ under ambient condition. This is among the highest device performance for n-channel OTFTs processed from halogen-free solvents. The different thin-film morphologies, from featureless low crystalline morphology to well-aligned nanofibres, have a great effect on the device performance. These results might shed some light on solvent selection and the resulting solution process for organic electronic devices.

Carbazolo[2,1-a]carbazole Diimide: A Building Block for Organic Electronic Materials

Co-reporter:Dr. Zheng Zhao;Zhongli Wang;Xu Zhang;Simin Gao;Dr. Xiaodi Yang;Dr. Zhiming Duan;Dr. Xike Gao

ChemPlusChem 2015 Volume 80( Issue 1) pp:57-61

Publication Date(Web):

DOI:10.1002/cplu.201402360

Abstract

A new class of carbazolo[2,1-a]carbazole diimide compounds (CBZCBZ-DI, 3) are designed and synthesized. The synthesis, X-ray crystal structure, absorption spectra, and electrochemical properties of 3 as well as the charge transport properties are investigated. Theoretical calculation is also carried out based on the X-ray crystal structure of 3 a to understand the relationship between the structure and the charge transport properties. Single-crystal X-ray analysis revealed that the molecules of 3 a adopt a slipped face-to-face π-stacking mode with a large intermolecular π-overlap and an interplanar distance of 3.4 Å. Crystalline transistors of 3 a display high hole mobility of 0.5 cm² V⁻¹ s⁻¹, which is among the highest reported mobility values for carbazole-based N-heteroacenes. Two useful brominated derivatives (4, 5) are also prepared for synthesizing more new π-functional materials.

High mobility organic semiconductors for field-effect transistors

Co-reporter:Xike Gao;Zheng Zhao

Science China Chemistry 2015 Volume 58( Issue 6) pp:947-968

Publication Date(Web):2015 June

DOI:10.1007/s11426-015-5399-5

Organic field-effect transistors (OFETs) are attracting more and more attention due to their potential applications in low-cost, large-area and flexible electronic products. Organic semiconductors (OSCs) are the key components of OFETs and basically determine the device performance. The past five years have witnessed great progress of OSCs. OSCs used for OFETs have made rapid progress, with field-effect mobility much larger than that of amorphous silicon (0.5–1.0 cm2/(V s)) and of up to 10 cm2/(V s) or even higher. In this review, we demonstrate the latest progress of OSCs for OFETs, where more than 50 representative OSCs are highlighted and analyzed to give some valuable insights for this important but challenging field.

Development of n-type organic semiconductors for thin film transistors: a viewpoint of molecular design

Co-reporter:Xike Gao and Yunbin Hu

Journal of Materials Chemistry A 2014 vol. 2(Issue 17) pp:3099-3117

Publication Date(Web):28 Nov 2013

DOI:10.1039/C3TC32046D

The past ten years have witnessed great progress of n-type organic semiconductors (OSCs) for organic thin film transistors (OTFTs), while the device performance and ambient stability of n-type OSCs are still outmatched by their p-type counterparts. The pursuit of high-performance ambient-stable n-type OSCs for OTFTs is highly desirable for realizing robust, large-area and low-cost organic integrated circuits. In this feature article, we'll review the development of n-type OSCs for OTFTs from a viewpoint of molecular design, where more than nine molecular design strategies with >120 representative n-type OSCs are summarized and analyzed to give some valuable insights for this significant but challenging field.

Naphthalenediimides Fused with 2-(1,3-Dithiol-2-ylidene)acetonitrile: Strong Electron-Deficient Building Blocks for High-Performance n-Type Polymeric Semiconductors

Co-reporter:Zheng Zhao, Fengjiao Zhang, Yunbin Hu, Zhongli Wang, Bing Leng, Xike Gao, Chong-an Di, and Daoben Zhu

ACS Macro Letters 2014 Volume 3(Issue 11) pp:1174

Publication Date(Web):October 24, 2014

DOI:10.1021/mz500603f

Naphthalenediimides (NDI) fused with two 2-(1,3-dithiol-2-ylidene)acetonitrile moieties (NDI-DTYA2), a novel strong electron-deficient monomer, was designed and readily synthesized by aromatic nucleophilic substitution to develop n-type polymers. Two NDI-DTYA2 based donor–acceptor (D–A) polymers P(NDI-DTYA2–1T) and P(NDI-DTYA2–2T) have been prepared (1T = thiophene, 2T = 2,2′-bithiophene) and showed low-lying LUMO energies (<−4.2 eV) and near-infrared optical absorptions (optical band gap <1.3 eV). Although the film feature of these polymers is amorphous, pure electron transport with high mobility of up to 0.38 cm2 V –1 s –1 could be achieved for their bottom gate organic thin film transistors, which was among the highest performances for unipolar n-type polymers. The results demonstrate that NDI-DTYA2 derivatives are promising building blocks for developing electron transport π-functional materials.

Tuning the Charge Transport Property of Naphthalene Diimide Derivatives by Changing the Substituted Position of Fluorine Atom on Molecular Backbone

Co-reporter:Xiao Zhang;Zhongli Wang;Shiyan Chen;Zheng Zhao;Wei Yuan;Huaping Wang

Chinese Journal of Chemistry 2014 Volume 32( Issue 10) pp:1057-1064

Publication Date(Web):

DOI:10.1002/cjoc.201400488

Abstract

Three naphthalene diimides (2, 3 and 4) fused with 2-(1,3-dithiol-2-ylidene)-2-fluorophenylacetonitrile moieties were designed and synthesized. Due to the different substituted positions of fluorine atom on the phenyl group, the solution-processed thin films of 2 and 3 operated in air as n-channel transistors, while the films of 4 performed as ambipolar transistors, indicating that the variation of substituted position of fluorine atom on molecular backbone may tune the material's charge transport behavior.

Critical Role of Alkyl Chain Branching of Organic Semiconductors in Enabling Solution-Processed N-Channel Organic Thin-Film Transistors with Mobility of up to 3.50 cm2 V–1 s–1

Co-reporter:Fengjiao Zhang ; Yunbin Hu ; Torben Schuettfort ; Chong-an Di ; Xike Gao ; Christopher R. McNeill ; Lars Thomsen ; Stefan C. B. Mannsfeld ; Wei Yuan ; Henning Sirringhaus ;Daoben Zhu

Journal of the American Chemical Society 2013 Volume 135(Issue 6) pp:2338-2349

Publication Date(Web):January 18, 2013

DOI:10.1021/ja311469y

Substituted side chains are fundamental units in solution processable organic semiconductors in order to achieve a balance of close intermolecular stacking, high crystallinity, and good compatibility with different wet techniques. Based on four air-stable solution-processed naphthalene diimides fused with 2-(1,3-dithiol-2-ylidene)malononitrile groups (NDI-DTYM2) that bear branched alkyl chains with varied side-chain length and different branching position, we have carried out systematic studies on the relationship between film microstructure and charge transport in their organic thin-film transistors (OTFTs). In particular synchrotron measurements (grazing incidence X-ray diffraction and near-edge X-ray absorption fine structure) are combined with device optimization studies to probe the interplay between molecular structure, molecular packing, and OTFT mobility. It is found that the side-chain length has a moderate influence on thin-film microstructure but leads to only limited changes in OTFT performance. In contrast, the position of branching point results in subtle, yet critical changes in molecular packing and leads to dramatic differences in electron mobility ranging from ∼0.001 to >3.0 cm2 V–1 s–1. Incorporating a NDI-DTYM2 core with three-branched N-alkyl substituents of C11,6 results in a dense in-plane molecular packing with an unit cell area of 127 Å2, larger domain sizes of up to 1000 × 3000 nm2, and an electron mobility of up to 3.50 cm2 V–1 s–1, which is an unprecedented value for ambient stable n-channel solution-processed OTFTs reported to date. These results demonstrate that variation of the alkyl chain branching point is a powerful strategy for tuning of molecular packing to enable high charge transport mobilities.

A facile synthesis of 2,3,6,7-tetrabromonaphthalene diimides toward new π-extended naphthalene diimides

Co-reporter:Yunbin Hu, Zhongli Wang, Xiaodi Yang, Zheng Zhao, Wenjie Han, Wei Yuan, Hongxiang Li, Xike Gao, Daoben Zhu

Tetrahedron Letters 2013 Volume 54(Issue 18) pp:2271-2273

Publication Date(Web):1 May 2013

DOI:10.1016/j.tetlet.2013.02.075

A 2,3,6,7-tetrabromonaphthalene diimide (2) was readily synthesized in high yield from 2,3,6,7-tetrabromonaphthalene dianhydride by an improved dehydrohalogenation-based imidization reaction. The further nucleophilic aromatic substitution (SNAr) reaction of 2 with potassium cyanocarbonimidodithioate afforded a new π-extended naphthalene diimide (1), which exhibits n-type behavior in organic transistors and interesting response to F− among halide anions in solutions.A 2,3,6,7-tetrabromonaphthalene diimide (2) was readily synthesized in high yield from 2,3,6,7-tetrabromonaphthalene dianhydride by an improved dehydrohalogenation-based imidization reaction. The further nucleophilic aromatic substitution (SNAr) reaction of 2 with potassium cyanocarbonimidodithioate afforded a new π-extended naphthalene diimide (1), which exhibits n-type behavior in organic transistors and interesting response to F− among halide anions in solutions.

New Core-Expanded Naphthalene Diimides for n-Channel Organic Thin Film Transistors

Co-reporter:Yunbin Hu;Zhongli Wang;Xu Zhang;Xiaodi Yang;Hongxiang Li

Chinese Journal of Chemistry 2013 Volume 31( Issue 11) pp:1428-1438

Publication Date(Web):

DOI:10.1002/cjoc.201300585

Abstract

Four classes of core-expanded naphthalene diimides (1a, 1b, 2a, 2b, 3 and 4) that bear different electron-deficient sulfur heterocycles were designed and synthesized. The solution-processed thin films of 1a, 2a, 3 and 4 operated well in air as n-channel organic transistors with electron mobility ranging from ∼10⁻⁶ to 0.14 cm²/Vs, depending on the different conjugated backbones. The thin film microstructure studies were also carried out to understand the variations of the electron mobility for thin films of 1a, 2a, 3 and 4.

1,2,5,6-Naphthalenediimide Based Donor–Acceptor Copolymers Designed from Isomer Chemistry for Organic Semiconducting Materials

Co-reporter:Zheng Zhao, Fengjiao Zhang, Xu Zhang, Xiaodi Yang, Hongxiang Li, Xike Gao, Chong-an Di, and Daoben Zhu

Macromolecules 2013 Volume 46(Issue 19) pp:7705-7714

Publication Date(Web):September 17, 2013

DOI:10.1021/ma4013994

Two new donor–acceptor (D–A) copolymers based on 1,2,5,6-naphthalenediimides (iso-NDI) and thiophene units, iso-P(NDI2OD-T2) and iso-P(NDI2OD-TT), were designed from isomer chemistry and compared with the reported isomeric copolymers P(NDI2OD-T2) and P(NDI2DT-TT) to investigate the influence of isomeric structure on their optoelectronic properties. DFT calculations reveal that iso-P(NDI2OD-T2) and iso-P(NDI2OD-TT) have higher HOMO and LUMO energies and better backbone planarity relative to their isomeric polymers. Iso-P(NDI2OD-T2) and iso-P(NDI2OD-TT) were synthesized by the Stille coupling polymerization and characterized by elemental analysis, 1H NMR, GPC, UV–vis absorption, cyclic voltammetry, TGA, DSC, and organic thin film transistors (OTFTs). It was found that iso-P(NDI2OD-T2) and iso-P(NDI2OD-TT) had higher LUMO energies and broader band gaps than their isomeric ones and showed hole-dominated charge transport behavior, which is quite different from the electron-dominated charge transport feature of P(NDI2OD-T2) and P(NDI2DT-TT). In spite of the amorphous-like thin-film features, iso-P(NDI2OD-T2) exhibited high hole mobility of up to 0.3 cm2 V–1 s–1, and iso-P(NDI2OD-TT) showed ambipolar property with hole and electron mobility of up to 0.02 and 4 × 10–3 cm2 V–1 s–1, respectively.

Tetracyanodibenzotetrathiafulvalene Diimides: Design, Synthesis, and Property Study

Co-reporter:Zheng Zhao, Zhongli Wang, Yunbin Hu, Xiaodi Yang, Hongxiang Li, Xike Gao, and Daoben Zhu

The Journal of Organic Chemistry 2013 Volume 78(Issue 23) pp:12214-12219

Publication Date(Web):November 5, 2013

DOI:10.1021/jo401916f

Tetracyanodibenzotetrathiafulvalene diimide (TCDBTTF-DI), an isomer of core-expanded naphthalene diimides bearing two 2-(1,3-dithiol-2-ylidene)malononitrile moieties (NDI-DTYM2), has been designed and synthesized to explore the effect of its isomeric structure on the optical and electrochemical properties of the materials. UV–vis spectra show that TCDBTTF-DI exhibits variation in its absorption peaks while maintaining a similar optical band gap to NDI-DTYM2. Electrochemical studies indicate that TCDBTTF-DI can not only accept but also lose electrons, in contrast to the solely electron-accepting behavior of NDI-DTYM2.

One-Pot Synthesis of Core-Expanded Naphthalene Diimides: Enabling N-Substituent Modulation for Diverse n-Type Organic Materials

Co-reporter:Yunbin Hu, Yunke Qin, Xike Gao, Fengjiao Zhang, Chong-an Di, Zheng Zhao, Hongxiang Li, and Daoben Zhu

Organic Letters 2012 Volume 14(Issue 1) pp:292-295

Publication Date(Web):December 9, 2011

DOI:10.1021/ol203059r

A mild and versatile one-pot synthesis of core-expanded naphthalene diimides has been developed, which undergoes a nucleophilic aromatic substitution reaction and then an imidization reaction, allowing an easy and low-cost access to diverse n-type organic materials. Some newly synthesized compounds by this one-pot operation exhibited high electron mobility of up to 0.70 cm2 V–1 s–1 in ambient conditions.

Core-Expanded Naphthalene Diimides Fused with Sulfur Heterocycles and End-Capped with Electron-Withdrawing Groups for Air-Stable Solution-Processed n-Channel Organic Thin Film Transistors

Co-reporter:Yunbin Hu, Xike Gao, Chong-an Di, Xiaodi Yang, Feng Zhang, Yunqi Liu, Hongxiang Li, and Daoben Zhu

Chemistry of Materials 2011 Volume 23(Issue 5) pp:1204

Publication Date(Web):January 20, 2011

DOI:10.1021/cm102850j

Four families of core-expanded naphthalene diimide (NDI) derivatives were designed and synthesized, namely, NDI-DTYM2 (1−7, of which 1 and 2 were previously reported), NDI-DTDCN2 (8 and 9), NDI-DTYCA2 (10 and 11), and NDI-DCT2 (12), where the NDI core fuses two 2-(1,3-dithiol-2-ylidene)malonitrile (DTYM) groups, two 1,4-dithiine-2,3-dicarbonitrile (DTDCN) groups, two alkyl 2-(1,3-dithiol-2-ylidene)cyanoacetate (DTYCA) groups, and two 2,3-dicyanothiophenes (DCT), respectively. The NDI cores of the present compounds bear the branched N-alkyl substituents with the carbon atom numbers from 12 to 24, which guarantees good material solubility. The solution-processed, bottom-gate organic thin film transistors based on new compounds 3−12 operate well in air with the electron mobility ranging from ∼10−6 to 0.26 cm2 V−1 s−1, depending on the nature of the branched N-alkyl substituent and the π-backbone structure.Keywords: characterization of materials; electronic materials; semiconductors;

Core-Expanded Naphthalene Diimides Fused with 2-(1,3-Dithiol-2-Ylidene)Malonitrile Groups for High-Performance, Ambient-Stable, Solution-Processed n-Channel Organic Thin Film Transistors

Co-reporter:Xike Gao ; Chong-an Di ; Yunbin Hu ; Xiaodi Yang ; Hongyu Fan ; Feng Zhang ; Yunqi Liu ; Hongxiang Li ;Daoben Zhu

Journal of the American Chemical Society 2010 Volume 132(Issue 11) pp:3697-3699

Publication Date(Web):February 26, 2010

DOI:10.1021/ja910667y

A new class of n-type semiconductors for organic thin film transistors (OTFTs), based on core-expanded naphthalene diimides fused with 2-(1,3-dithiol-2-ylidene)malonitrile groups, is reported. The first two representatives of these species, derived from long branched N-alkyl chains, have been successfully used as active layers for high-performance, ambient-stable, solution-processed n-channel OTFTs. Their bottom-gate top-contact devices fabricated by spin-coating methods exhibit high electron mobilities of up to 0.51 cm2 V−1 s−1 with current on/off ratios of 105−107, and small threshold voltages below 10 V under ambient conditions. As this class of n-type organic semiconductors has relatively low-lying LUMO levels and good film-formation ability, they also displayed good environmental stability even with prolonged exposure to ambient air. Both the device performance and the ambient stability are among the best for n-channel OTFTs reported to date.

Development of n-type organic semiconductors for thin film transistors: a viewpoint of molecular design

Co-reporter:Xike Gao and Yunbin Hu

Journal of Materials Chemistry A 2014 - vol. 2(Issue 17) pp:NaN3117-3117

Publication Date(Web):2013/11/28

DOI:10.1039/C3TC32046D

Synthesis of largely π-extended naphthalenediimides via C–H activation towards highly soluble and narrow band-gap organic optoelectronic materials

Co-reporter:Wenting Wu, Jing Li, Zheng Zhao, Xiaodi Yang and Xike Gao

Inorganic Chemistry Frontiers 2017 - vol. 4(Issue 5) pp:NaN827-827

Publication Date(Web):2017/03/22

DOI:10.1039/C7QO00061H

Biazulene diimides: a new building block for organic electronic materials

Co-reporter:Hanshen Xin, Congwu Ge, Xiaodi Yang, Honglei Gao, Xiaochun Yang and Xike Gao

Chemical Science (2010-Present) 2016 - vol. 7(Issue 11) pp:NaN6705-6705

Publication Date(Web):2016/07/19

DOI:10.1039/C6SC02504H

Azulene, a 10-π-electron isomer of naphthalene, is a nonbenzenoid bicyclic aromatic hydrocarbon with a beautiful blue color and a large dipole moment. We present here the first class of azulene-based aromatic diimides, 2,2′-biazulene-1,1′,3,3′-tetracarboxylic diimides (BAzDIs), which comprise a 2,2′-biazulene moiety and two seven-membered imide groups. DFT calculations, thermal, optical and electrochemical properties of two BAzDI derivatives as well as single crystal analysis and the charge transport behavior were studied. The results demonstrate that BAzDIs have unique photophysical properties and are promising for organic electronic materials.

Dithieno[3,2-a:3′,2′-j][5,6,11,12]chrysene diimides and their molecular energy level regulation

Co-reporter:Xueqian Zhao, Congwu Ge, Xiaodi Yang and Xike Gao

Inorganic Chemistry Frontiers 2017 - vol. 1(Issue 8) pp:NaN1640-1640

Publication Date(Web):2017/05/04

DOI:10.1039/C7QM00030H