Co-reporter:Dazhen Huang, Huiying Yao, Yutao Cui, Ye Zou, Fengjiao Zhang, Chao Wang, Hongguang Shen, Wenlong Jin, Jia Zhu, Ying Diao, Wei Xu, Chong-an Di, and Daoben Zhu
Journal of the American Chemical Society September 20, 2017 Volume 139(Issue 37) pp:13013-13013
Publication Date(Web):August 18, 2017
DOI:10.1021/jacs.7b05344
Conjugated backbones play a fundamental role in determining the electronic properties of organic semiconductors. On the basis of two solution-processable dihydropyrrolo[3,4-c]pyrrole-1,4-diylidenebis(thieno[3,2-b]thiophene) derivatives with aromatic and quinoid structures, we have carried out a systematic study of the relationship between the conjugated-backbone structure and the thermoelectric properties. In particular, a combination of UV–vis–NIR spectra, photoemission spectroscopy, and doping optimization are utilized to probe the interplay between energy levels, chemical doping, and thermoelectric performance. We found that a moderate change in the conjugated backbone leads to varied doping mechanisms and contributes to dramatic changes in the thermoelectric performance. Notably, the chemically doped A-DCV-DPPTT, a small molecule with aromatic structure, exhibits an electrical conductivity of 5.3 S cm–1 and a high power factor (PF373 K) up to 236 μW m–1 K–2, which is 50 times higher than that of Q-DCM-DPPTT with a quinoid structure. More importantly, the low thermal conductivity enables A-DCV-DPPTT to possess a figure of merit (ZT) of 0.23 ± 0.03, which is the highest value reported to date for thermoelectric materials based on organic small molecules. These results demonstrate that the modulation of the conjugated backbone represents a powerful strategy for tuning the electronic structure and mobility of organic semiconductors toward a maximum thermoelectric performance.
Co-reporter:Dafei Yuan, Dazhen Huang, Cheng Zhang, Ye Zou, Chong-an Di, Xiaozhang Zhu, and Daoben Zhu
ACS Applied Materials & Interfaces August 30, 2017 Volume 9(Issue 34) pp:28795-28795
Publication Date(Web):August 11, 2017
DOI:10.1021/acsami.7b07282
To achieve efficient n-type doping, three dopants, 2-Cyc-DMBI-H, (2-Cyc-DMBI)2, and (2-Cyc-DMBI-Me)2, with precisely regulated electron-donating ability were designed and synthesized. By doping with a small-molecule 2DQTT-o-OD with high electron mobility, an unexpectedly high power factor of 33.3 μW m–1 K–2 was obtained with the new dopant (2-Cyc-DMBI-Me)2. Notably, with the intrinsically low lateral thermal conductivity of 0.28 W m–1 K–1, the figure of merit was determined to be 0.02 at room temperature. Thus, we have demonstrated that small molecules with high electron mobility and low-lying LUMO energy levels can achieve high doping efficiency and excellent thermoelectric properties by doping with n-type dopants featuring highly matched energy levels and excellent miscibility.Keywords: energy level; n-type doping; organic thermoelectrics; small molecule; solution-processed;
Co-reporter:Hongguang Shen;Daoben Zhu
Science China Chemistry 2017 Volume 60( Issue 4) pp:437-449
Publication Date(Web):2017 April
DOI:10.1007/s11426-016-9014-9
Organic field-effect transistors (OFETs) are recently considered to be attractive candidate for bioelectronic applications owing to their prominent biocompatibility, intrinsical flexibility, and potentially low cost associated with their solution processibility. Over the last few years, bioelectronic-application-motivated OFETs have attracted increasing attention towards next generation of biosensors, healthcare elements and artificial neural interfaces. This mini review highlights the basic principles and recent progress in OFET based bioelectronics devices. The key strategies and the forecast perspectives of this research field are also briefly summarized.
Co-reporter:Liyao Liu;Yuanhui Sun;Wenbo Li;Jiajia Zhang;Xing Huang;Zhijun Chen;Yimeng Sun;Chongan Di;Wei Xu;Daoben Zhu
Materials Chemistry Frontiers 2017 vol. 1(Issue 10) pp:2111-2116
Publication Date(Web):2017/09/27
DOI:10.1039/C7QM00223H
By printing polydimethylsiloxane (PDMS) on a polyethylene terephthalate (PET) substrate as a mask, an insoluble and infusible metal coordination polymer, poly[Kx(Ni-ethylenetetrathiolate)] (poly[Kx(Ni-ett)]), film was patterned via an electrochemical deposition process. The method is verified to be capable of fabricating 108 n-type legs in one batch. A thermoelectric generator consisting of eighteen legs connected in series in one row had an output power of 0.468 μW under a temperature difference of 12 K with the best power density reaching up to 577.8 μW cm−2.
Co-reporter:Yaping Zang;Hongguang Shen;Dazhen Huang;Daoben Zhu
Advanced Materials 2017 Volume 29(Issue 18) pp:
Publication Date(Web):2017/05/01
DOI:10.1002/adma.201606088
Organic-device-based tactile-perception systems can open up new opportunities for the next generation of intelligent products. To meet the critical requirements of artificial perception systems, the efficient construction of organic smart elements with integrated sensing and signal processing functionalities is highly desired, but remains a challenge. This study presents a dual-organic-transistor-based tactile-perception element (DOT-TPE) with biomimetic functionality by the construction of organic synaptic transistors with integrated sensing transistors. The unique geometry of the DOT-TPE permits instantaneous sensing of pressure stimuli and synapse-like processing of an electric signal in a single element. More importantly, these organic-transistor-based tactile-perception elements can be built into arrays to serve as bionic tactile-perception systems. The combined biomimetic functionality of tactile-perception systems, together with their promising features of flexibility and large-area fabrication, makes this work represent a step forward toward novel e-skin devices for artificial intelligence.
Co-reporter:Cheng Zhang;Dafei Yuan;Hao Wu;Eliot Gann;Lars Thomsen;Christopher R. McNeill;Xiaozhang Zhu;Daoben Zhu
Journal of Materials Chemistry C 2017 vol. 5(Issue 8) pp:1935-1943
Publication Date(Web):2017/02/23
DOI:10.1039/C6TC05052B
Control of molecular ordering and packing of π-conjugated molecules in the solid state is crucial for enhancing the charge transport properties in organic electronics. A series of quinoidal materials based on different alkyl-chain branching positions on the thieno[3,4-c]pyrrole-4,6-dione moiety flanked with unsymmetric thieno[3,4-b]thiophenes (2DQTT-n) are synthesized. By the combination of organic thin-film transistor performances and thin-film characterization, we clarified the influence of the branching position on the film microstructure/molecular packing and charge transport properties. Air-stable solution-processable n-channel 2DQTT-n derivatives show dramatic changes in film morphology and molecular packing, which leads to disparate electron mobilities ranging from ∼0.34 to 4.5 cm2 V−1 s−1. 2DQTT-1 with a branching point at the two-position in the alkyl side chain results in a 3D molecular packing with a lamellate morphology, and an electron mobility of up to 4.5 cm2 V−1 s−1 using an annealing temperature of just 80 °C. In contrast, the other three materials exhibit polymorphs and 2DQTT-3 and 2DQTT-4 even show mix-oriented crystallites which are highly disadvantageous to charge transport. These results demonstrate that variation of the alkyl-chain branching point is a powerful strategy to tune the stacking modes in the thin-film state, which enables high charge transport properties.
Co-reporter:Yaping Zang;Dazhen Huang;Daoben Zhu
Advanced Materials 2016 Volume 28( Issue 22) pp:4549-4555
Publication Date(Web):
DOI:10.1002/adma.201505034
Organic thin-film transistors (OFETs) represent a promising candidate for next-generation sensing applications because of the intrinsic advantages of organic semiconductors. The development of flexible sensing devices has received particular interest in the past few years. The recent efforts of developing OFETs for sensitive and specific flexible sensors are summarized from the standpoint of device engineering. The tuning of signal transduction and signal amplification are highlighted based on an overview of active-layer thickness modulation, functional receptor implantation and device geometry optimization.
Co-reporter:Dazhen Huang;Dr. Chao Wang;Dr. Ye Zou;Xingxing Shen;Yaping Zang;Hongguang Shen; Xike Gao; Yuanping Yi; Wei Xu;Dr. Chong-an Di; Daoben Zhu
Angewandte Chemie International Edition 2016 Volume 55( Issue 36) pp:10672-10675
Publication Date(Web):
DOI:10.1002/anie.201604478
Abstract
Development of chemically doped high performance n-type organic thermoelectric (TE) materials is of vital importance for flexible power generating applications. For the first time, bismuth (Bi) n-type chemical doping of organic semiconductors is described, enabling high performance TE materials. The Bi interfacial doping of thiophene-diketopyrrolopyrrole-based quinoidal (TDPPQ) molecules endows the film with a balanced electrical conductivity of 3.3 S cm−1 and a Seebeck coefficient of 585 μV K−1. The newly developed TE material possesses a maximum power factor of 113 μW m−1 K−2, which is at the forefront for organic small molecule-based n-type TE materials. These studies reveal that fine-tuning of the heavy metal doping of organic semiconductors opens up a new strategy for exploring high performance organic TE materials.
Co-reporter:Dazhen Huang;Dr. Chao Wang;Dr. Ye Zou;Xingxing Shen;Yaping Zang;Hongguang Shen; Xike Gao; Yuanping Yi; Wei Xu;Dr. Chong-an Di; Daoben Zhu
Angewandte Chemie 2016 Volume 128( Issue 36) pp:10830-10833
Publication Date(Web):
DOI:10.1002/ange.201604478
Abstract
Development of chemically doped high performance n-type organic thermoelectric (TE) materials is of vital importance for flexible power generating applications. For the first time, bismuth (Bi) n-type chemical doping of organic semiconductors is described, enabling high performance TE materials. The Bi interfacial doping of thiophene-diketopyrrolopyrrole-based quinoidal (TDPPQ) molecules endows the film with a balanced electrical conductivity of 3.3 S cm−1 and a Seebeck coefficient of 585 μV K−1. The newly developed TE material possesses a maximum power factor of 113 μW m−1 K−2, which is at the forefront for organic small molecule-based n-type TE materials. These studies reveal that fine-tuning of the heavy metal doping of organic semiconductors opens up a new strategy for exploring high performance organic TE materials.
Co-reporter:Yaping Zang;Fengjiao Zhang;Dazhen Huang;Daoben Zhu
Advanced Materials 2015 Volume 27( Issue 48) pp:7979-7985
Publication Date(Web):
DOI:10.1002/adma.201503542
Co-reporter:Ke Shi; Fengjiao Zhang; Chong-An Di; Tian-Wei Yan; Ye Zou; Xu Zhou; Daoben Zhu; Jie-Yu Wang;Jian Pei
Journal of the American Chemical Society 2015 Volume 137(Issue 22) pp:6979-6982
Publication Date(Web):May 21, 2015
DOI:10.1021/jacs.5b00945
Three n-type polymers BDPPV, ClBDPPV, and FBDPPV which exhibit outstanding electrical conductivities when mixed with an n-type dopant, N-DMBI ((4-(1,3-dimethyl-2,3-dihydro-1H-benzoimidazol-2-yl)phenyl)dimethylamine), in solution. High electron mobility and an efficient doping process endow FBDPPV with the highest electrical conductivities of 14 S cm–1 and power factors up to 28 μW m–1 K–2, which is the highest thermoelectric (TE) power factor that has been reported for solution processable n-type conjugated polymers. Our investigations reveal that introduction of halogen atoms to the polymer backbones has a dramatic influence on not only the electron mobilities but also the doping levels, both of which are critical to the electrical conductivities. This work suggests the significance of rational modification of polymer structures and opens the gate for applying the rapidly developed organic semiconductors with high carrier mobilities to thermoelectric field.
Co-reporter:Fengjiao Zhang;Yaping Zang;Dazhen Huang;Xike Gao;Henning Sirringhaus;Daoben Zhu
Advanced Functional Materials 2015 Volume 25( Issue 20) pp:3004-3012
Publication Date(Web):
DOI:10.1002/adfm.201404397
Organic thermoelectric materials, which can transform heat flow into electricity, have great potential for flexible, ultra-low-cost and large-area thermoelectric applications. Despite rapid developments of organic thermoelectric materials, exploration and investigation of promising organic thermoelectric semiconductors still remain as a challenge. Here, the thermoelectric properties of several p- and n-type organic semiconductors are investigated and studied, in particular, how the electric field modulations of the Seebeck coefficient in organic field-effect transistors (OFETs) compare with the Seebeck coefficient in chemically doped films. The extracted relationship between the Seebeck coefficient (S) and electrical conductivity (σ) from the field-effect transistor (FET) geometry is in good agreement with that of chemically doped films, enabling the investigation of the trade-off relationship among σ, S, carrier concentration, and charging level. The results make OFETs an effective candidate for the thermoelectric studies of organic semiconductors.
Co-reporter:Yaping Zang, Fengjiao Zhang, Chong-an Di and Daoben Zhu
Materials Horizons 2015 vol. 2(Issue 2) pp:140-156
Publication Date(Web):17 Oct 2014
DOI:10.1039/C4MH00147H
By virtue of their wide applications in personal electronic devices and industrial monitoring, pressure sensors are attractive candidates for promoting the advancement of science and technology in modern society. Flexible pressure sensors based on organic materials, which combine unique advantages of flexibility and low-cost, have emerged as a highly active field due to their promising applications in artificial intelligence systems and wearable health care devices. In this review, we focus on the fundamentals of flexible pressure sensors, and subsequently on several critical concepts for the exploration of functional materials and optimization of sensing devices toward practical applications. Perspectives on self-powered, transparent and implantable pressure sensing devices are also examined to highlight the development directions in this exciting research field.
Co-reporter:Yuanhui Sun, Fengjiao Zhang, Yimeng Sun, Chong-an Di, Wei Xu and Daoben Zhu
Journal of Materials Chemistry A 2015 vol. 3(Issue 6) pp:2677-2683
Publication Date(Web):08 Dec 2014
DOI:10.1039/C4TA06475E
We report the synthesis and thermoelectric (TE) performance of organometallic coordination polymers, including copper 7,7,8,8-tetracyano-p-quinodimethane nanocrystals (NC-CuTCNQ) and thin films of CuTCNQ nanorod arrays (NrA-CuTCNQ). The characterization of NC-CuTCNQ was carried out with the compressed samples. For NrA-CuTCNQ films, the TE properties were investigated with a hybrid Au/Cu/CuTCNQ/Au architecture along the direction either vertical or parallel to the film surface and obviously anisotropic behaviors were observed. We found that CuTCNQ can be a potential n-type material for future application in thermoelectric devices with a power factor of 1.5 μW m−1 K−2, accompanied by a high Seebeck coefficient of −632 μV K−1 at 370 K. In order to optimize its TE performance, a cousin molecule 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) was mixed with TCNQ reacted with CuI. We found that the CuTCNQ blend possessed the highest power factor of 2.5 μW m−1 K−2 with a 1 mol% blend ratio of F4TCNQ (related to TCNQ) at 370 K.
Co-reporter:Dazhen Huang, Ye Zou, Fei Jiao, Fengjiao Zhang, Yaping Zang, Chong-an Di, Wei Xu, and Daoben Zhu
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 17) pp:8968
Publication Date(Web):April 15, 2015
DOI:10.1021/acsami.5b01460
Organic photothermoelectric (PTE) materials are promising candidates for various photodetection applications. Herein, we report on poly[Cux(Cu-ett)]:PVDF, which is an excellent polymeric thermoelectric composite, possesses unprecedented PTE properties. The NIR light irradiation on the poly[Cux(Cu-ett)]:PVDF film could induce obvious enhancement in Seebeck coefficient from 52 ± 1.5 to 79 ± 5.0 μV/K. By taking advantage of prominent photothermoelectric effect of poly[Cux(Cu-ett)]:PVDF, an unprecedented voltage of 12 mV was obtained. This excellent performance enables its promising applications in electricity generation from solar energy and NIR detection to a wide range of light intensities ranging from 1.7 mW/cm2 to 17 W/cm2.Keywords: NIR detection; organic thermoelectric device; organic thermoelectric material; photothermoelectric effect;
Co-reporter:Yaping Zang;Fengjiao Zhang;Dazhen Huang;Qing Meng;Xike Gao;Daoben Zhu
Advanced Materials 2014 Volume 26( Issue 18) pp:2862-2867
Publication Date(Web):
DOI:10.1002/adma.201305011
Co-reporter:Cheng Zhang ; Yaping Zang ; Eliot Gann ; Christopher R. McNeill ; Xiaozhang Zhu ; Chong-an Di ;Daoben Zhu
Journal of the American Chemical Society 2014 Volume 136(Issue 46) pp:16176-16184
Publication Date(Web):October 28, 2014
DOI:10.1021/ja510003y
Quinoidal oligothiophenes (QOT), as classical n-type semiconductors, have been well-known for a long time but with non-optimal semiconducting properties. We report here the design and selective synthesis of new two-dimensional (2D) π-expanded quinoidal terthiophenes, 2DQTTs, with proximal (2DQTT-i) and distal (2DQTT-o) regiochemistry for high-performance n-channel organic thin-film transistors (n-OTFTs) featuring high electron mobility, solution processability, and ambient stability. The elegant combination of thieno[3,4-b]thiophene [TT, donor (D)] and 5-alkyl-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione [TPD, acceptor (A)] units with relatively large π-surface endows these 2DQTTs with distinctive 2D structural characteristics and flat configuration stabilized by weak intramolecular S–O/S weak interactions. Furthermore, the A–D–A–D–A electronic structure maintains an adequately low LUMO energy level. These 2DQTTs are shown to exhibit outstanding semiconducting properties with electron mobilities of up to 3.0 cm2 V–1 s–1 and on/off ratios of up to 106 (2DQTT-o) in ambient- and solution-processed OTFTs. Investigations on thin-film morphology reveal that the microstructure of 2DQTTs is highly dependent on the orientation of the fused thiophene subunits, leading to differences in electron mobilities of 1 order of magnitude. X-ray diffraction studies in particular reveal increased crystallinity, crystalline coherence, and orientational order in 2DQTT-o compared to 2DQTT-i, which accounts for the superior electron transport property of 2DQTT-o.
Co-reporter:Qing Meng, Fengjiao Zhang, Yaping Zang, Dazhen Huang, Ye Zou, Jie Liu, Guangyao Zhao, Zongrui Wang, Deyang Ji, Chong-an Di, Wenping Hu and Daoben Zhu
Journal of Materials Chemistry A 2014 vol. 2(Issue 7) pp:1264-1269
Publication Date(Web):06 Jan 2014
DOI:10.1039/C3TC31762E
The solution-shearing technique is utilized to fabricate large-area, ultrathin and continuous films of 1,4-bis((5′-hexyl-2,2′-bithiophen-5-yl)ethynyl)benzene (HTEB) for high-performance organic thin-film transistors (OTFTs), based on which highly sensitive, highly selective and reversible gas sensors exhibit outstanding response to NH3, with detection limit as low as 100 ppb.
Co-reporter:Fei Jiao, Fengjiao Zhang, Yaping Zang, Ye Zou, Chong'an Di, Wei Xu and Daoben Zhu
Chemical Communications 2014 vol. 50(Issue 18) pp:2374-2376
Publication Date(Web):09 Jan 2014
DOI:10.1039/C3CC49448A
Ultrathin carbon films were prepared by carbonization of a solution processed polyacrylonitrile (PAN) film in a moderate temperature range (500–700 °C). The films displayed balanced hole (0.50 cm2 V−1 s−1) and electron mobilities (0.20 cm2 V−1 s−1) under ambient conditions. Spectral characterization revealed that the electrical transport is due to the formation of sp2 hybridized carbon during the carbonization process. A CMOS-like inverter demonstrated the potential application of this material in the area of carbon electronics, considering its processability and low-cost.
Co-reporter:Wenli Tang, Dazhen Huang, Chang He, Yuanping Yi, Jing Zhang, Chongan Di, Zhanjun Zhang, Yongfang Li
Organic Electronics 2014 Volume 15(Issue 6) pp:1155-1165
Publication Date(Web):June 2014
DOI:10.1016/j.orgel.2014.03.005
•Two A-π-D-π-A type indacenodithiophene-based small molecules have been designed and synthesized.•The indacenodithiophene-based small molecules exhibit good performance of OFETs and OPVs simultaneously.•Side chain positions of the π-bridges in the molecules influence the performance of the OFETs and OPVs.•The power conversion efficiency of the OSCs based on the molecules as donor reached ca. 3%.Solution-processed indacenodithiophene (IDT)-based small molecules with 1,3-indanedione (ID) as terminal acceptor units and 3,3′-hexyl-terthiophene (IDT-3Th-ID(I)) or 4,4′-hexyl-terthiophene (IDT-3Th-ID(II)) as π-bridges, have been designed and synthesized for the application in organic field-effect transistors (OFETs) and organic solar cells (OSCs). These molecules exhibited excellent solubility in common organic solvents, good film-forming ability, reasonable thermal stability, and low HOMO energy levels. For the OFETs devices, high hole motilities of 0.52 cm2 V−1 s−1 for IDT-3Th-ID(I) and 0.61 cm2 V−1 s−1 for IDT-3Th-ID(II) were achieved, with corresponding high ION/IOFF of ca. 107 and ∼109 respectively. The OSCs based on IDT-3Th-ID(I)/PC70BM (2:1, w/w) and IDT-3Th-ID(II)/PC70BM (2:1, w/w) without using any treatment of solvent additive or thermal annealing, showed power conversion efficiencies (PCEs) of 3.07% for IDT-3Th-ID(I) and 2.83% for IDT-3Th-ID(II), under the illumination of AM 1.5G, 100 mW/cm2. The results demonstrate that the small molecules constructed with the highly π-conjugated IDT as donor unit, 3Th as π-bridges and ID as acceptor units, could be promising organic semiconductors for high-performance OFETs and OSCs applications.Graphical abstract
Co-reporter:Chao Wang;Yaping Zang;Yunke Qin;Qian Zhang;Yuanhui Sun;Dr. Chong-an Di; Wei Xu; Daoben Zhu
Chemistry - A European Journal 2014 Volume 20( Issue 42) pp:13755-13761
Publication Date(Web):
DOI:10.1002/chem.201403037
Abstract
We report the synthesis, characterization, redox behavior, and n-channel organic field-effect (OFET) characteristics of a new class of thieno[3,2-b]thiophene-diketopyrrolopyrrole-based quinoidal small molecules 3 and 4. Under ambient atmosphere, solution-processed thin-film transistors based on 3 and 4 exhibit maximum electron mobilities up to 0.22 and 0.16 cm2 V−1 s−1, respectively, with on-off current ratios (Ion/Ioff) of more than than 106. Cyclic voltammetry analysis showed that this class of quinoidal derivatives exhibited excellent reversible two-stage reduction behavior. This property was further investigated by a stepwise reductive titration of 4, in which sequential reduction to the radical anion and then the dianion were observed.
Co-reporter:Yuanyuan Hu, Nikolai Berdunov, Chong-an Di, Iris Nandhakumar, Fengjiao Zhang, Xike Gao, Daoben Zhu, and Henning Sirringhaus
ACS Nano 2014 Volume 8(Issue 7) pp:6778
Publication Date(Web):June 18, 2014
DOI:10.1021/nn500944f
We have investigated the influence of the symmetry of the side chain substituents in high-mobility, solution processable n-type molecular semiconductors on the performance of organic field-effect transistors (OFETs). We compare two molecules with the same conjugated core, but either symmetric or asymmetric side chain substituents, and investigate the transport properties and thin film growth mode using scanning Kelvin probe microscopy (SKPM) and atomic force microscopy (AFM). We find that asymmetric side chains can induce a favorable two-dimensional growth mode with a bilayer structure, which enables ultrathin films with a single bilayer to exhibit excellent transport properties, while the symmetric molecules adopt an unfavorable three-dimensional growth mode in which transport in the first monolayer at the interface is severely hindered by high-resistance grain boundaries.Keywords: field-effect transistors; intralayer and interlayer transport; Kelvin probe microscopy; molecule symmetry
Co-reporter:Chong-an Di;Fengjiao Zhang;Daoben Zhu
Advanced Materials 2013 Volume 25( Issue 3) pp:313-330
Publication Date(Web):
DOI:10.1002/adma.201201502
Co-reporter:Fengjiao Zhang;Nikolai Berdunov;Yuanyuan Hu;Yunbin Hu;Xike Gao;Qing Meng;Henning Sirringhaus;Daoben Zhu
Advanced Materials 2013 Volume 25( Issue 10) pp:1401-1407
Publication Date(Web):
DOI:10.1002/adma.201204075
Co-reporter:Fengjiao Zhang;Nikolai Berdunov;Yuanyuan Hu;Yunbin Hu;Xike Gao;Qing Meng;Henning Sirringhaus;Daoben Zhu
Advanced Materials 2013 Volume 25( Issue 10) pp:
Publication Date(Web):
DOI:10.1002/adma.201370062
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.
Co-reporter:Zhe Qi, Fengjiao Zhang, Chong-an Di, Jizheng Wang and Daoben Zhu
Journal of Materials Chemistry A 2013 vol. 1(Issue 18) pp:3072-3077
Publication Date(Web):25 Mar 2013
DOI:10.1039/C3TC30357H
Brush painting, a simple and fast solution processing technique, possesses promising multiple applications in ultra-low-cost organic electronics with large-area manufacture. Benefiting from effective brush painting of high quality conductive electrodes, semiconductive layers and dielectric layers, all-brush-painted top-gate transistors were successfully constructed with a maximum mobility of 0.14 cm2 V−1 s−1.
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.
Co-reporter:Yimeng Sun;Peng Sheng;Chongan Di;Fei Jiao;Wei Xu;Dong Qiu;Daoben Zhu
Advanced Materials 2012 Volume 24( Issue 7) pp:932-937
Publication Date(Web):
DOI:10.1002/adma.201104305
Co-reporter:Jianyu Yuan, Xiaodong Huang, Fengjiao Zhang, Jialing Lu, Zhichun Zhai, Chongan Di, Zuoquan Jiang and Wanli Ma
Journal of Materials Chemistry A 2012 vol. 22(Issue 42) pp:22734-22742
Publication Date(Web):11 Sep 2012
DOI:10.1039/C2JM34004F
Three low-band-gap donor–acceptor (D–A) copolymers containing benzo(1,2-b:4,5-b′)dithiophene (BDT), 3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (TDP) or 3,6-di(furan-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (FDP) were designed and synthesized. Their thermal stability, optical and electrochemical properties, device performances for organic field effect transistors (OFETs) and polymer solar cells were systematically investigated. The device performances were significantly enhanced by the introduction of conjugated alkylthienyl side chains to the BDT core and the substitution of thiophene with furan moieties in polymer backbone. Compared to alkoxy side chains, conjugated alkylthienyl chains resulted in higher coplanarity, increased thermal stability (Td increased from 364 °C to 417 °C) and a lower HOMO level (from −5.10 eV to −5.24 eV). The incorporation of furan evidently improved the polymer solubility, leading to a finer phase separation morphology as proved by atomic force microscopy and transmission electron microscopy. After optimization, the designed polymer showed excellent performance in both OFETs and PSCs with an optimal hole mobility of 0.16 cm2 V−1 s−1 and a high power conversion efficiency of 5.54%.
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.
Co-reporter:Yan Zhao;Xike Gao;Yunbin Hu;Yunlong Guo;Lei Zhang;Yunqi Liu;Jizheng Wang;Wenping Hu;Daoben Zhu
Advanced Materials 2011 Volume 23( Issue 21) pp:
Publication Date(Web):
DOI:10.1002/adma.201190076
Co-reporter:Yan Zhao;Xike Gao;Yunbin Hu;Yunlong Guo;Lei Zhang;Yunqi Liu;Jizheng Wang;Wenping Hu;Daoben Zhu
Advanced Materials 2011 Volume 23( Issue 21) pp:2448-2453
Publication Date(Web):
DOI:10.1002/adma.201004588
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;
Co-reporter:Lei Zhang;Yan Zhao;Yunlong Guo;Xiangnan Sun;Yugeng Wen;Weiyi Zhou;Xiaowei Zhan;Gui Yu;Yunqi Liu
Advanced Materials 2010 Volume 22( Issue 32) pp:3537-3541
Publication Date(Web):
DOI:10.1002/adma.201000123
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.
Co-reporter:Qing Meng, Fengjiao Zhang, Yaping Zang, Dazhen Huang, Ye Zou, Jie Liu, Guangyao Zhao, Zongrui Wang, Deyang Ji, Chong-an Di, Wenping Hu and Daoben Zhu
Journal of Materials Chemistry A 2014 - vol. 2(Issue 7) pp:NaN1269-1269
Publication Date(Web):2014/01/06
DOI:10.1039/C3TC31762E
The solution-shearing technique is utilized to fabricate large-area, ultrathin and continuous films of 1,4-bis((5′-hexyl-2,2′-bithiophen-5-yl)ethynyl)benzene (HTEB) for high-performance organic thin-film transistors (OTFTs), based on which highly sensitive, highly selective and reversible gas sensors exhibit outstanding response to NH3, with detection limit as low as 100 ppb.
Co-reporter:Zhe Qi, Fengjiao Zhang, Chong-an Di, Jizheng Wang and Daoben Zhu
Journal of Materials Chemistry A 2013 - vol. 1(Issue 18) pp:NaN3077-3077
Publication Date(Web):2013/03/25
DOI:10.1039/C3TC30357H
Brush painting, a simple and fast solution processing technique, possesses promising multiple applications in ultra-low-cost organic electronics with large-area manufacture. Benefiting from effective brush painting of high quality conductive electrodes, semiconductive layers and dielectric layers, all-brush-painted top-gate transistors were successfully constructed with a maximum mobility of 0.14 cm2 V−1 s−1.
Co-reporter:Cheng Zhang, Dafei Yuan, Hao Wu, Eliot Gann, Lars Thomsen, Christopher R. McNeill, Chong-an Di, Xiaozhang Zhu and Daoben Zhu
Journal of Materials Chemistry A 2017 - vol. 5(Issue 8) pp:NaN1943-1943
Publication Date(Web):2017/01/17
DOI:10.1039/C6TC05052B
Control of molecular ordering and packing of π-conjugated molecules in the solid state is crucial for enhancing the charge transport properties in organic electronics. A series of quinoidal materials based on different alkyl-chain branching positions on the thieno[3,4-c]pyrrole-4,6-dione moiety flanked with unsymmetric thieno[3,4-b]thiophenes (2DQTT-n) are synthesized. By the combination of organic thin-film transistor performances and thin-film characterization, we clarified the influence of the branching position on the film microstructure/molecular packing and charge transport properties. Air-stable solution-processable n-channel 2DQTT-n derivatives show dramatic changes in film morphology and molecular packing, which leads to disparate electron mobilities ranging from ∼0.34 to 4.5 cm2 V−1 s−1. 2DQTT-1 with a branching point at the two-position in the alkyl side chain results in a 3D molecular packing with a lamellate morphology, and an electron mobility of up to 4.5 cm2 V−1 s−1 using an annealing temperature of just 80 °C. In contrast, the other three materials exhibit polymorphs and 2DQTT-3 and 2DQTT-4 even show mix-oriented crystallites which are highly disadvantageous to charge transport. These results demonstrate that variation of the alkyl-chain branching point is a powerful strategy to tune the stacking modes in the thin-film state, which enables high charge transport properties.
Co-reporter:Jianyu Yuan, Xiaodong Huang, Fengjiao Zhang, Jialing Lu, Zhichun Zhai, Chongan Di, Zuoquan Jiang and Wanli Ma
Journal of Materials Chemistry A 2012 - vol. 22(Issue 42) pp:NaN22742-22742
Publication Date(Web):2012/09/11
DOI:10.1039/C2JM34004F
Three low-band-gap donor–acceptor (D–A) copolymers containing benzo(1,2-b:4,5-b′)dithiophene (BDT), 3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (TDP) or 3,6-di(furan-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (FDP) were designed and synthesized. Their thermal stability, optical and electrochemical properties, device performances for organic field effect transistors (OFETs) and polymer solar cells were systematically investigated. The device performances were significantly enhanced by the introduction of conjugated alkylthienyl side chains to the BDT core and the substitution of thiophene with furan moieties in polymer backbone. Compared to alkoxy side chains, conjugated alkylthienyl chains resulted in higher coplanarity, increased thermal stability (Td increased from 364 °C to 417 °C) and a lower HOMO level (from −5.10 eV to −5.24 eV). The incorporation of furan evidently improved the polymer solubility, leading to a finer phase separation morphology as proved by atomic force microscopy and transmission electron microscopy. After optimization, the designed polymer showed excellent performance in both OFETs and PSCs with an optimal hole mobility of 0.16 cm2 V−1 s−1 and a high power conversion efficiency of 5.54%.
Co-reporter:Fei Jiao, Fengjiao Zhang, Yaping Zang, Ye Zou, Chong'an Di, Wei Xu and Daoben Zhu
Chemical Communications 2014 - vol. 50(Issue 18) pp:NaN2376-2376
Publication Date(Web):2014/01/09
DOI:10.1039/C3CC49448A
Ultrathin carbon films were prepared by carbonization of a solution processed polyacrylonitrile (PAN) film in a moderate temperature range (500–700 °C). The films displayed balanced hole (0.50 cm2 V−1 s−1) and electron mobilities (0.20 cm2 V−1 s−1) under ambient conditions. Spectral characterization revealed that the electrical transport is due to the formation of sp2 hybridized carbon during the carbonization process. A CMOS-like inverter demonstrated the potential application of this material in the area of carbon electronics, considering its processability and low-cost.
Co-reporter:Yuanhui Sun, Fengjiao Zhang, Yimeng Sun, Chong-an Di, Wei Xu and Daoben Zhu
Journal of Materials Chemistry A 2015 - vol. 3(Issue 6) pp:NaN2683-2683
Publication Date(Web):2014/12/08
DOI:10.1039/C4TA06475E
We report the synthesis and thermoelectric (TE) performance of organometallic coordination polymers, including copper 7,7,8,8-tetracyano-p-quinodimethane nanocrystals (NC-CuTCNQ) and thin films of CuTCNQ nanorod arrays (NrA-CuTCNQ). The characterization of NC-CuTCNQ was carried out with the compressed samples. For NrA-CuTCNQ films, the TE properties were investigated with a hybrid Au/Cu/CuTCNQ/Au architecture along the direction either vertical or parallel to the film surface and obviously anisotropic behaviors were observed. We found that CuTCNQ can be a potential n-type material for future application in thermoelectric devices with a power factor of 1.5 μW m−1 K−2, accompanied by a high Seebeck coefficient of −632 μV K−1 at 370 K. In order to optimize its TE performance, a cousin molecule 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) was mixed with TCNQ reacted with CuI. We found that the CuTCNQ blend possessed the highest power factor of 2.5 μW m−1 K−2 with a 1 mol% blend ratio of F4TCNQ (related to TCNQ) at 370 K.
![Stannane, 1,1'-[4,8-bis[5-(2-ethylhexyl)-2-thienyl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl]bis[1,1,1-trimethyl-](/data/chemimg/139400/1352642-37-5.png)
![Stannane, 1,1'-[4,8-bis[5-(2-ethylhexyl)-2-thienyl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl]bis[1,1,1-trimethyl-](/data/chemimg/139400/1352642-37-5_b.png)
![4H-Thieno[3,4-c]pyrrole-4,6(5H)-dione, 1,3-bis(5-bromo-2-thienyl)-5-(2-ethylhexyl)-](/data/chemimg/139500/1286745-60-5.png)
![4H-Thieno[3,4-c]pyrrole-4,6(5H)-dione, 1,3-bis(5-bromo-2-thienyl)-5-(2-ethylhexyl)-](/data/chemimg/139500/1286745-60-5_b.png)
![3,6-Bis(thieno[3,2-b]thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione](http://img.cochemist.com/ccimg/1246700/1246679-11-7.png)
![3,6-Bis(thieno[3,2-b]thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione](http://img.cochemist.com/ccimg/1246700/1246679-11-7_b.png)
![4H-Thieno[3,4-c]pyrrole-4,6(5H)-dione, 1,3-dibromo-5-(2-octyldodecyl)-](/data/chemimg/148300/1234271-15-8.png)
![4H-Thieno[3,4-c]pyrrole-4,6(5H)-dione, 1,3-dibromo-5-(2-octyldodecyl)-](/data/chemimg/148300/1234271-15-8_b.png)
![4H-Thieno[3,4-c]pyrrole-4,6(5H)-dione, 1,3-dibromo-5-(2-ethylhexyl)-](/data/chemimg/139500/1231160-83-0.png)
![4H-Thieno[3,4-c]pyrrole-4,6(5H)-dione, 1,3-dibromo-5-(2-ethylhexyl)-](/data/chemimg/139500/1231160-83-0_b.png)
![Poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene]](http://img.cochemist.com/ccimg/888500/888491-19-8.png)
![Poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene]](http://img.cochemist.com/ccimg/888500/888491-19-8_b.png)
![1,3-dibromo-5-(n-dodecyl)thieno[3,4-c]pyrrole-4,6-dione](http://img.cochemist.com/ccimg/773900/773881-47-3.png)
![1,3-dibromo-5-(n-dodecyl)thieno[3,4-c]pyrrole-4,6-dione](http://img.cochemist.com/ccimg/773900/773881-47-3_b.png)
![4,5,9,10-Tetrabromoisochromeno[6,5,4-def]isochromene-1,3,6,8-tetraone](http://img.cochemist.com/ccimg/300000/299962-88-2.png)
![4,5,9,10-Tetrabromoisochromeno[6,5,4-def]isochromene-1,3,6,8-tetraone](http://img.cochemist.com/ccimg/300000/299962-88-2_b.png)
![Thieno[3,2-b]thiophene-2-carbonitrile](http://img.cochemist.com/ccimg/41000/40985-58-8.png)
![Thieno[3,2-b]thiophene-2-carbonitrile](http://img.cochemist.com/ccimg/41000/40985-58-8_b.png)
![Thieno[3,4-b]thiophene](/data/chemimg/417100/250-65-7.png)
![Thieno[3,4-b]thiophene](/data/chemimg/417100/250-65-7_b.png)
