Zhang Hantang    Lang Jiang    Zhen Yonggang    Zhang Jing    Han Guang-Chao    Zhang Xiaotao    Fu Xiaolong    Yuanping Yi    Wei Xu    Huanli Dong    Chen Wei    Wenping Hu    朱道本    

Advanced Electronic Materials

2016

Doping and thermoelectric properties of two solution-processable conjugated polymers with low ionization potentials (IPs) have been studied and compared. An optimized thermoelectric power factor (PF) approaching 40 μW m K at 390 K was achieved in films of polymer PDTPT-C12, by performing doping treatment with LiTFSI solution in air, while an optimized thermoelectric power factor around 12 μW m K at 390 K was observed when CuTFSI solution was used instead of LiTFSI. In contrast, such effects on thermoelectric performance as a result of dopant species were not observed in the other studied polymer PTVT2T-C12 with comparable IP. Based on the results of thermoelectric measurements and optical spectroscopy as well as photoelectron spectroscopy, the role of Li in the resultant thermoelectric performance was proposed. Moreover, owing to the relatively low IPs of the two studied polymers, the as-doped polymer films are reasonably stable under ambient conditions. Therefore, N-alkyl dithieno[3,2b:2′,3′-d] pyrroles (DTPs) as exemplified in the case of PDTPT-C12 are suggested to be promising building-blocks and the incorporation of small cations like Li may be an alternative to increase the thermopower in solid state devices.

Zhang Qian    Yimeng Sun    Qin Yunke    Wei Xu    朱道本    

Journal of Materials Chemistry A

2016

Comprehensive investigations of crystal structures, electrical transport properties and theoretical simulations have been performed over a series of sulfur-bridged annulene-based donor-acceptor complexes with an alternate stacking motif. A remarkably high mobility, up to 1.57 cm V s for holes and 0.47 cm V s for electrons, was obtained using organic single crystal field-effect transistor devices, demonstrating the efficient ambipolar transport properties. These ambipolar properties arise from the fact that the electronic couplings for both holes and electrons have the same super-exchange nature along the alternate stacking direction. The magnitude of super-exchange coupling depends not only on the intermolecular stacking distance and pattern, but also the energy level alignments between the adjacent donor-acceptor moieties. The concluded transport mechanism and structure-property relationship from this research will provide an important guideline for the future design of organic semiconductors based on donor-acceptor complexes.

Qin Yunke    Cheng Changli    Geng Hua    Wang Chao    Wenping Hu    Wei Xu    Zhigang Shuai    朱道本    

Physical Chemistry Chemical Physics

2016

Carbon films prepared from pyrolyzation of spin-casted polyacrylonitrile (PAN) thin films display high electrical conductivity (>600 S/cm, at 1000 °C carbonization), low sheet resistance (about 100 Ω/square at the PAN film thickness of 70 nm) and partial transmittance. These pyrolyzed PAN (PPAN) films were patterned as bottom electrodes by photolithography, and utilized as drain and source electrodes to fabricate organic field-effect transistor (OFET) devices with a p-type semiconductor (P3HT) and an n-type semiconductor (DPP-containing quinoidal small molecule) through a spin-coating procedure. The results showed that the devices with the PAN electrodes exhibited almost the same excellent performance without any further modification compared to those devices with traditional Au electrodes. Since these PPAN films had the advantages of low-cost, high performance, easier for large-area fabrication, thermal and chemical stability, it should be a promising electrode material for organic electrodes.

Zhang Jiajia    Wang Chao    Chen Jie    Sun Yuanhui    Yan Jie    Ye Zou    Wei Xu    朱道本    

Science China Chemistry

2016

A step by step crystal-to-crystal transformation was observed from the 1D tetrahydrate compound KCu(CO)(HO) (1) to the 1D dihydrate compound KCu(CO)(HO) (2), and finally the 1D dehydrated compound KCu(CO) (3) by the loss of half the amount of HO and all HO molecules, with structural and magnetic changes.

Zhang Bin    Zhang Y.    Zhang J.    Yan X.    朱道本    

CrystEngComm

2016

A radical cation salt composed of an organic donor, BEDT-TTF, and a one-dimensional inorganic anion, [Fe(CO)Cl ], was obtained by electrocrystallization, and was identified as a semiconductor with values of σ = 3.0 × 10 S cm. Spin-canted antiferromagnetic long-range ordering was observed at 5.5 K from ZFCM/FCM/RM measurement and confirmed using AC measurement.

Zhang Bin    Zhang Yan    Wang Z.    Yang D.    Gao Z.    Wang Dongwei    Yanjun Guo    朱道本     Takehiko Mori   

Dalton Transactions

2016

Using in situ ultraviolet photoelectron spectroscopy, the electronic structure evolutions at the interface between pentacene and fullerene (C), a classical organic donor-acceptor heterostructure in organic electronic devices, on indium-tin oxide (ITO) and MoOmodified ITO substrates have been investigated. The insertion of a thin layer MoOhas a significant impact on the interfacial energy level alignment of pentacene-Cheterostructure. For the deposition of Con pentacene, the energy difference between the highest occupied molecular orbital of donor and the lowest unoccupied molecular orbital of acceptor (HOMO-LUMO) offset of C/pentacene heterostructure increased from 0.86 eV to 1.54 eV after the insertion of a thin layer MoOon ITO. In the inverted heterostructrure where pentacene was deposited on C, the HOMO-LUMOoffset of pentacene/Cheterostructure increased from 1.32 to 2.20 eV after MoOmodification on ITO. The significant difference of HOMO-LUMOoffset shows the feasibility to optimize organic electronic device performance through interfacial engineering approaches, such as the insertion of a thin layer high work function MoOfilms.

Ye Zou    Mao Hongying    Qing Meng    朱道本    

Journal of Chemical Physics

2016

A series of thiophene-diketopyrrolopyrrole-based quinoidal small molecules (TDPPQ-2-TDPPQ-5) bearing branched alkyl chains with different side-chain lengths and varied branching positions are synthesized. Field-effect transistor (FET) measurement combined with thin-film characterization is utilized to systematically probe the influence of the side-chain length and branching position on the film microstructure, molecular packing, and, hence, charge-transport property. All of these TDPPQ derivatives show air-stable n-channel transporting behavior in spin-coated FET devices, which exhibit no significant decrease in mobility even after being stored in air for 2 months. Most notably, TDPPQ-3 exhibits an outstanding n-channel semiconducting property with electron mobilities up to 0.72 cm² V^-1 s^-1, which is an unprecedented value for spin-coated DPP-based n-type semiconducting small molecules. A balance of high crystallinity, satisfactory thickness uniformity and continuity, and strong intermolecular interaction accounts for the superior charge-transport characteristics of TDPPQ-3 films. Our study demonstrates that tuning the length and branching position of alkyl side chains of semiconducting molecules is a powerful strategy for achieving high FET performance. (Figure Presented).

Wang Chao    Qin Yunke    Sun Yuanhui    Guan Ying-Shi    Xu Wei    朱道本    

ACS Applied Materials and Interfaces

2015

Hongtao Zhang    Hui Jingshu    Chen Hongliang    Chen Jianming    Xu Wei    Zhigang Shuai    朱道本     郭雪峰   

Advanced Electronic Materials

2015

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 cm V s) and electron mobilities (0.20 cm V s) under ambient conditions. Spectral characterization revealed that the electrical transport is due to the formation of sp 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. © The Royal Society of Chemistry 2014.

Fei Jiao    Fengjiao Zhang    Yaping Zang    Ye Zou    Chongan Di    Wei Xu    朱道本    

Chemical Communications

2014