Cyano-substituted benzochalcogenadiazole-based polymer semiconductors for balanced ambipolar organic thin-film transistors

Shi, Shengbin,Wang, Hang,Chen, Peng,Uddin, Mohammad Afsar,Wang, Yuxi,Tang, Yumin,Guo, Han,Cheng, Xing,Zhang, Shiming,Woo, Han Young,Guo, Xugang The Royal Society of Chemistry 2018 Polymer chemistry Vol.9 No.28

<P>Due to their high-lying lowest unoccupied molecular orbitals (LUMOs), π-conjugated polymers based on benzothiadiazole and its derivatives typically are p-type. We report here the successful development of two narrow bandgap, ambipolar donor-acceptor copolymers, PDCNBT2T and PDCNBSe2T, which are based on new cyano-substituted strong electron acceptors, 4,7-dibromo-5,6-dicyano-2,1,3-benzothiadiazole (DCNBT) and 4,7-dibromo-5,6-dicyano-2,1,3-benzoselenadiazole (DCNBSe), respectively. Compared to their polymer analogues with fluorine substituents, the LUMO was lowered by a big margin of <I>ca.</I> 0.6 eV and the bandgap was reduced by 0.2-0.3 eV for the cyano-substituted polymers. Therefore, the cyano-substituted benzothiadiazole polymers showed very low-lying LUMO levels of <I>ca.</I> 4.3 eV. Benefiting from their narrow bandgaps of 1.1-1.2 eV and appropriately positioned LUMO levels, both polymers exhibit well balanced ambipolar transport characteristics in organic thin-film transistors, which differ from the p-type dominating transport properties of their fluorinated polymer analogues. A balanced hole/electron mobility of 0.59/0.47 cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP> was achieved for polymer PDCNBT2T, and a reduced hole/electron mobility of 0.018/0.014 cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP> was observed for the benzoselenadiazole-based PDCNBSe2T due to its lower crystallinity. These results show that the electron mobility can be enhanced by approximately two orders <I>versus</I> the electron mobility of the previously reported 4,7-di(thiophen-2-yl)-5,6-dicyano-2,1,3-benzothiadiazole-based polymer. This improvement was achieved by using the new acceptor units without additional electron-rich thiophene flanks, which allow a higher degree of freedom in selecting the donor co-unit and more effective tuning of energy levels of frontier molecular orbitals.</P>

Head-to-Head Linked Dialkylbifuran-Based Polymer Semiconductors for High-Performance Organic Thin-Film Transistors with Tunable Charge Carrier Polarity

Shi, Shengbin,Wang, Hang,Uddin, Mohammad Afsar,Yang, Kun,Su, Mengyao,Bianchi, Luca,Chen, Peng,Cheng, Xing,Guo, Han,Zhang, Shiming,Woo, Han Young,Guo, Xugang American Chemical Society 2019 Chemistry of materials Vol.31 No.5

<P>A planar backbone conformation is essential for enabling polymer semiconductors with high charge carrier mobility in organic thin-film transistors. Benefiting from the smaller van der Waals radius of the O atom in furan (versus the S atom in thiophene), alkylated furan exerts a reduced steric hindrance on neighboring arene, and it was found that the head-to-head (HH)-linked 3,3′-dialkyl-2,2′-bifuran (<B>BFR</B>) can attain a high degree of backbone planarity. Hence, <B>BFR</B> should be a promising building block for constructing polymer semiconductors with a planar backbone conformation and hold distinctive advantages over a dialkylbithiophene-based analogue, which is typically highly twisted. The alkyl chains on the 3 and 3′ positions offer good solubility to the resulting polymers, which in combination with its planar backbone yields an improved molecular design window for developing high-performance polymer semiconductors, particularly those with a simple molecular structure and based on the acceptor co-unit without any solubilizing chains. When incorporated into polymer semiconductors, remarkably high hole and electron mobilities of 1.50 and 0.31 cm<SUP>2</SUP> V<SUP>-1</SUP> s<SUP>-1</SUP> are obtained for <B>BFR</B>-based polymers <B>FBFR-BO</B> and <B>CNBFR-C18</B> containing fluorinated and cyano-functionalized benzothiadiazole as the acceptor co-unit, respectively. Such mobilities are the highest values for HH-linked polymers and also among the best for furan-containing polymers. The results demonstrate that HH-linked dialkylbifuran is a highly promising building block for constructing organic and polymeric semiconductors, and this new approach by incorporating HH <B>BFR</B> offers several distinctive advantages for developing high-performance polymer semiconductors, including effective optoelectronic property tuning using a minimal number of aromatic rings, reduced structural complexity, facile material synthesis, good material solubility, and enriching the material library. In addition, the study offers important guidelines for future development of furan-based polymers and head-to-head linkage containing organic semiconductors.</P> [FIG OMISSION]</BR>

Dynamic evolution of buyer-supplier relationships based on game theory

Zhao Shengbin,Shi Chunsheng 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10

Supplier relationship management is one of the core links in supplier chain management. A dynamic evolution model of buyer-supplier relationships is constructed based on dynamic game with incomplete information to improve supplier relationship management. Four buyer-supplier relationships are founded by interdependence between buyer and suppliers, which are called advantage relationship, disadvantage relationship, complementation relationship and equal relationship. And dynamic evolution of buyer-supplier relationships is znalyzed. Finally strategies of supplier relationship management are put forward according to dynamic evolution of supplier relationship and practical experiences. It is expected that the research can help the practice or theory of supplier management.

Cyano-Substituted Head-to-Head Polythiophenes: Enabling High-Performance n-Type Organic Thin-Film Transistors

Wang, Hang,Huang, Jun,Uddin, Mohammad Afsar,Liu, Bin,Chen, Peng,Shi, Shengbin,Tang, Yumin,Xing, Guichuan,Zhang, Shiming,Woo, Han Young,Guo, Han,Guo, Xugang American Chemical Society 2019 ACS APPLIED MATERIALS & INTERFACES Vol.11 No.10

<P>Polythiophenes, built on the electron-rich thiophene unit, typically possess high-lying energy levels of the lowest unoccupied molecular orbitals (LUMOs) and show hole-transporting properties. In this study, we develop a series of n-type polythiophenes, <B>P1</B>-<B>P3</B>, based on head-to-head-linked 3,3′-dialkoxy-4,4′-dicyano-2,2′-bithiophene (BTCNOR) with distinct side chains. The BTCNOR unit shows not only highly planar backbone conformation enabled by the intramolecular noncovalent sulfur-oxygen interaction but also significantly suppressed LUMO level attributed to the cyano-substitution. Hence, all BTCNOR-based polymer semiconductors exhibit low-lying LUMO levels, which are ∼1.0 eV lower than that of regioregular poly(3-hexylthiophene) (rr-P3HT), a benchmark p-type polymer semiconductor. Consequently, all of the three polymers can enable unipolar n-type transport characteristics in organic thin-film transistors (OTFTs) with low off-currents (<I>I</I><SUB>off</SUB>s) of 10<SUP>-10</SUP>-10<SUP>-11</SUP> A and large current on/off ratios (<I>I</I><SUB>on</SUB>/<I>I</I><SUB>off</SUB>s) at the level of 10<SUP>6</SUP>. Among them, polymer <B>P2</B> with a 2-ethylhexyl side chain offers the highest film ordering, leading to the best device performance with an excellent electron mobility (μ<SUB>e</SUB>) of 0.31 cm<SUP>2</SUP> V<SUP>-1</SUP> s<SUP>-1</SUP> in off-center spin-cast OTFTs. To the best of our knowledge, this is the first report of n-type polythiophenes with electron mobility comparable to the hole mobility of the benchmark p-type rr-P3HT and approaching the electron mobility of the most-studied n-type polymer, poly(naphthalene diimide-<I>alt</I>-bithiophene) (i.e., N2200). The change of charge carrier polarity from p-type (rr-P3HT) to n-type (<B>P2</B>) with comparable mobility demonstrates the obvious effectiveness of our structural modification. Adoption of <I>n</I>-hexadecyl (<B>P1</B>) and 2-butyloctyl (<B>P3</B>) side chains leads to reduced film ordering and results in 1-2 orders of magnitude lower μ<SUB>e</SUB>s, showing the critical role of side chains in optimizing device performance. This study demonstrates the unique structural features of head-to-head linkage containing BTCNOR for constructing high-performance n-type polymers, i.e., the alkoxy chain for backbone conformation locking and providing polymer solubility as well as the strong electron-withdrawing cyano group for lowering LUMO levels and enabling n-type performance. The design strategy of BTCNOR-based polymers provides useful guidelines for developing n-type polythiophenes.</P> [FIG OMISSION]</BR>

Synergistic photocatalysis of bimetal mixed ZIFs in enhancing degradation of organic pollutants: Experimental and computational studies

Weihao Zhu,Yuanfeng Wu,Guiyun Yi,Xiaoxiao Su,Qiangsheng Pan,Shengbin Shi,Olayinka Oderinde,Guomin Xiao,Chuanxiang Zhang,Yulong Zhang 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.119 No.-

The present work is aimed at studying the synergistic catalysis of the bimetal ZIFs containing Co and Znmetal ions prepared by solvothermal method in the degradation of organic pollutants under ambientconditions. The bimetal mixed ZIFs were further characterized by some techniques such as XRD, SEM,TG-DTG, XPS, UV–vis, ESR, and N2-adsorption. Interestingly, the sample prepared with equal metal ions(1Zn:1Co) showed the highest catalytic performance for methylene blue (MB) degradation (94.10 %). Thismay be associated with the interaction between cobalt and zinc within the adjacent lattice, which makethe MB molecule to be easily adsorbed and degraded on empty electron orbit. Furthermore, the highestdegradation of MB was achieved with 98.83 % under the optimized conditions (catalyst weight of 50 mg,pH of 5, 3 h, 30 C). Besides, the various substrates such as methyl orange, indole, rofloxacin, methyl blue,and tetracycline were also investigated under the same conditions. Additionally, the DFT calculationresults suggested the more orbital distribution (LUMO, HOMO) of ZIF(1Zn:1Co) can result to more electronsbeing easily captured, and generate more radicals via electron transfer. Finally, the photocatalyticdegradation of MB is consistent with the first law of kinetics, and the activation energy is 26.797 KJ/molin the presence of ZIF(1Zn:1Co).