Department of Chemistry

Department of Chemistry
Science Building, Block A (SA)
Xi'an Jiaotong-Liverpool University
111 Ren'ai Road Suzhou Dushu Lake Science and Education Innovation District , Suzhou Industrial Park
Suzhou,Jiangsu Province,P. R. China,215123

1. 2,2-Dicyanovinyl-end-capped oligothiophenes as electron acceptor in solution processed bulk-heterojunction organic solar cells

Author:Wu, J;Ma, Y;Wu, N;Lin, Y;Lin, J;Wang, L;Ma, CQ


Abstract:Three 2,2-dicyanovinyl (DCV) end-capped A-pi-D-pi-A type oligothiophenes (DCV-OTs) containing dithieno[3,2-b: 2',3'-d] silole (DTSi), cyclopenta[1,2-b: 3,4-b'] dithiophene (DTCP) or dithieno[3,2-b: 2',3'-d] pyrrole (DTPy) unit as the central donor part, mono-thiophene as the pi-conjugation bridge were synthesized. The absorption spectroscopies, cyclic voltammetry of these compounds were characterized. Results showed that all these compounds have intensive absorption band over 500-680 nm with a LUMO energy level around -3.80 eV, which is slightly higher than that of [6,6] phenyl-C-61-butyric acid methyl ester (PC61BM, E-LUMO = -4.01 eV), but lower than that of poly(3-hexylthiophene) (P3HT, ELUMO = -2.91 eV). Solution processed bulk heterojunction "all-thiophene'' solar cells using P3HT as electron donor and the above mentioned oligothiophenes as electron acceptor were fabricated and tested. The highest power conversion efficiency (PCE) of 1.31%% was achieved for DTSi-cored compound DTSi(THDCV) 2, whereas PTB7: DTSi(THDCV) 2 based device showed slightly higher PCE of 1.56%%. Electron mobilities of these three compounds were measured to be around 10 (5) cm(2) V (1) s (1) by space charge limited current method, which is much lower than that of PC61BM, and was considered as one of the reason for the low photovoltaic performance. (C) 2015 Elsevier B.V. All rights reserved.
2. Dopamine Surface Modification of Trititanate Nanotubes: Proposed In-Situ Structure Models.

Author:Liu, Ruochen; Fu, Xuejian; Wang, Congyi; Dawson, Graham

Source:Chemistry (Weinheim an der Bergstrasse, Germany),2016,Vol.22

Abstract:Two models for self-assembled dopamine on the surface of trititanate nanotubes are proposed: individual monomer units linked by π-π stacking of the aromatic regions and mono-attached units interacting through hydrogen bonds. This was investigated with solid state NMR spectroscopy studies and powder X-ray diffraction.
3. An atomic finite element model for biodegradable polymers. Part 1. Formulation of the finite elements

Author:Gleadall, A;Pan, JZ;Ding, LF;Kruft, MA;Curco, D


Abstract:Molecular dynamics (MD) simulations are widely used to analyse materials at the atomic scale. However, MD has high computational demands, which may inhibit its use for simulations of structures involving large numbers of atoms such as amorphous polymer structures. An atomic-scale finite element method (AFEM) is presented in this study with significantly lower computational demands than MD. Due to the reduced computational demands, AFEM is suitable for the analysis of Young's modulus of amorphous polymer structures. This is of particular interest when studying the degradation of bioresorbable polymers, which is the topic of an accompanying paper. AFEM is derived from the inter-atomic potential energy functions of an MD force field. The nonlinear MD functions were adapted to enable static linear analysis. Finite element formulations were derived to represent interatomic potential energy functions between two, three and four atoms. Validation of the AFEM was conducted through its application to atomic structures for crystalline and amorphous poly(lactide). (C) 2015 Elsevier Ltd. All rights reserved.
4. Advances of RRAM Devices: Resistive Switching Mechanisms, Materials and Bionic Synaptic Application

Author:Shen, ZJ;Zhao, C;Qi, YF;Xu, WY;Liu, YN;Mitrovic, IZ;Yang, L;Zhao, CZ


Abstract:Resistive random access memory (RRAM) devices are receiving increasing extensive attention due to their enhanced properties such as fast operation speed, simple device structure, low power consumption, good scalability potential and so on, and are currently considered to be one of the next-generation alternatives to traditional memory. In this review, an overview of RRAM devices is demonstrated in terms of thin film materials investigation on electrode and function layer, switching mechanisms and artificial intelligence applications. Compared with the well-developed application of inorganic thin film materials (oxides, solid electrolyte and two-dimensional (2D) materials) in RRAM devices, organic thin film materials (biological and polymer materials) application is considered to be the candidate with significant potential. The performance of RRAM devices is closely related to the investigation of switching mechanisms in this review, including thermal-chemical mechanism (TCM), valance change mechanism (VCM) and electrochemical metallization (ECM). Finally, the bionic synaptic application of RRAM devices is under intensive consideration, its main characteristics such as potentiation/depression response, short-/long-term plasticity (STP/LTP), transition from short-term memory to long-term memory (STM to LTM) and spike-time-dependent plasticity (STDP) reveal the great potential of RRAM devices in the field of neuromorphic application.
5. A 9,9 '-spirobi[9H-fluorene]-cored perylenediimide derivative and its application in organic solar cells as a non-fullerene acceptor

Author:Yi, JD;Wang, YL;Luo, Q;Lin, Y;Tan, HW;Wang, HY;Ma, CQ


Abstract:A structurally non-planar molecule (SBF-PDI4) with a 9,9'-spirobi[9H-fluorene] (SBF) core and four perylenediimides (PDIs) at the periphery was designed, synthesized and characterized. This compound shows a low-lying LUMO energy level of -4.11 eV, which is similar to that of PCBM, but with intensive light absorption ability in the range 450-550 nm. A high power conversion efficiency (PCE) of 5.34%% was obtained for a solution processed bulk heterojunction solar cell (BHJSC) using SBF-PDI4 as the electron acceptor and a low-band gap polymer poly[[4,8-bis[5-(2-ethylhexyl)thiophene-2-yl]benzo[1,2-b: 4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]] (PTB7-Th) as the electron donor. These results demonstrate that PDI derivatives with a three dimensional molecular structure could serve as high performance electron acceptors in BHJSCs.
6. Flexible synthesis of polyfunctionalised 3-fluoropyrroles

Author:Cogswell, TJ;Donald, CS;Marquez, R


Abstract:An efficient and selective approach for the synthesis of polyfunctionalised 3-fluoropyrroles has been developed starting from commercial aldehydes. The methodology is concise, efficient and allows for the modular and systematic assembly of polysubstituted 3-fluoropyrroles. This synthesis provides an alternative and highly convergent strategy for the generation of these chemically and biologically important units.
7. Heterostructure nanocomposite with local surface plasmon resonance effect enhanced photocatalytic activity-a critical review

Author:Liu, Muye ; Kang, Qi ; Xie, Zhicheng ; Lu, Luhua ; Dai, Kai ; Dawson, Graham

Source:Journal of Physics D Applied Physics,2022,Vol.55

The unique characteristics of the local surface plasmon resonance (LSPR) effect endows heterostructure nanocomposite of noble metal (NM) nanoparticles and semiconducting materials with dramatically enhanced light absorption, charge separation and surface activity. In addition, they boost the development of research in photocatalytic fields including artificial photosynthesis, degradation of pollutants and deactivation of microorganisms. The advantages of using LSPR to improve the photocatalytic activity of semiconductor-based materials as well as the design and synthesis of NM nanoparticles with LSPR for photocatalytic applications have been widely studied in recent years and a great number of research works have been published in these areas. This review will introduce the concept of heterostructure nanocomposite, the basis of LSPR, controlled synthesis and the recent research progress involving applications of LSRP in artificial photosynthesis, degradation of pollutants and deactivation of microorganisms.
© 2021 IOP Publishing Ltd.
8. Three New Cu(Ⅱ) Supramolecular Isomers: One-pot Synthesis and Crystal Structures



Abstract:  Three Cu(Ⅱ)supramolecular isomers with different colors,{[Cu(L)(phen)]·xH2O·yDMF} n(x=0.5,y=0 for 1; x=0.25,y=0 for 2; x=y=0.5 for 3),were obtained from CuCl 2,phen and one V-shaped dicarboxylic acid(H 2 L)ligand in one-pot.1 belongs to monoclinic system with C2/c space group; 2 belongs to orthorhombic system,Pbca space group; 3 belongs to monoclinic system,P2(1)/c space group.The coordination modes of Cu(Ⅱ)in 3 compounds are different,octahedron for 1,square-plan for 2 and distorted square-plan for 3.The three compounds are all 1D chain structures,zigzag chains,helical chains and z-type chains for 1,2 and 3 respectively.The study of thermal stability and coordination energy comparison about the 3 isomers is in progress.
9. Effect of Annealing Temperature for Ni/AlOx/Pt RRAM Devices Fabricated with Solution-Based Dielectric

Author:Shen, ZJ;Qi, YF;Mitrovic, IZ;Zhao, CZ;Hall, S;Yang, L;Luo, T;Huang, YB;Zhao, C


Abstract:Resistive random access memory (RRAM) devices with Ni/AlOx/Pt-structure were manufactured by deposition of a solution-based aluminum oxide (AlOx) dielectric layer which was subsequently annealed at temperatures from 200 degrees C to 300 degrees C, in increments of 25 degrees C. The devices displayed typical bipolar resistive switching characteristics. Investigations were carried out on the effect of different annealing temperatures for associated RRAM devices to show that performance was correlated with changes of hydroxyl group concentration in the AlOx thin films. The annealing temperature of 250 degrees C was found to be optimal for the dielectric layer, exhibiting superior performance of the RRAM devices with the lowest operation voltage (<1.5 V), the highest ON/OFF ratio (>10(4)), the narrowest resistance distribution, the longest retention time (>10(4) s) and the most endurance cycles (>150).
10. Cortisol level dysregulation and its prevalence-Is it nature's alarm clock?

Author:Jones, C;Gwenin, C


Abstract:This review examines the stress hormone cortisol which plays an important role in regulating and supporting different bodily functions. Disruption in cortisol production has an impact on health and this review looks at a wide range of papers where cortisol has been indicated as a factor in numerous chronic conditions-especially those which are classed as "noncommunicable diseases" (NCDs). Timely detection, screening, and treatment for NCDs are vital to address the growing problem of NCDs worldwide-this would have health and socioeconomic benefits. Interestingly, many of the papers highlight the pro-inflammatory consequences of cortisol dysregulation and its deleterious effects on the body. This is particularly relevant given the recent findings concerning COVID-19 where pro-inflammatory cytokines have been implicated in severe inflammation.
11. Mutations in the pantothenate kinase of Plasmodium falciparum confer diverse sensitivity profiles to antiplasmodial pantothenate analogues

Author:Tjhin, ET;Spry, C;Sewell, AL;Hoegl, A;Barnard, L;Sexton, AE;Siddiqui, G;Howieson, VM;Maier, AG;Creek, DJ;Strauss, E;Marquez, R;Auclair, K;Saliba, KJ

Source:PLOS PATHOGENS,2018,Vol.14

Abstract:The malaria-causing blood stage of Plasmodium falciparum requires extracellular pantothenate for proliferation. The parasite converts pantothenate into coenzyme A (CoA) via five enzymes, the first being a pantothenate kinase (PfPanK). Multiple antiplasmodial pantothenate analogues, including pantothenol and CJ-15,801, kill the parasite by targeting CoA bio-synthesis/utilisation. Their mechanism of action, however, remains unknown. Here, we show that parasites pressured with pantothenol or CJ-15,801 become resistant to these analogues. Whole-genome sequencing revealed mutations in one of two putative PanK genes (Pfpank1) in each resistant line. These mutations significantly alter PfPanK activity, with two conferring a fitness cost, consistent with Pfpank1 coding for a functional PanK that is essential for normal growth. The mutants exhibit a different sensitivity profile to recently-described, potent, antiplasmodial pantothenate analogues, with one line being hypersensitive. We provide evidence consistent with different pantothenate analogue classes having different mechanisms of action: some inhibit CoA biosynthesis while others inhibit CoA-utilising enzymes.
12. Morphology dependent adsorption of methylene blue on trititanate nanoplates and nanotubes prepared by the hydrothermal treatment of TiO2

Author:Dawson, G;Chen, W;Lu, LH;Dai, K


Abstract:The adsorption properties of two nanomorphologies of trititanate, nanotubes (TiNT) and plates (TiNP), prepared by the hydrothermal reaction of concentrated NaOH with different phases of TiO2, were examined. It was found that the capacity for both morphologies towards methylene blue (MB), an ideal pollutant, was extremely high, with the TiNP having a capacity of 130 mg/g, higher than the TiNT, whose capacity was 120 mg/g at 10 mg/L MB concentration. At capacity, the well-dispersed powders deposit on the floor of the reaction vessel. The two morphologies had very different structural and adsorption properties. TiNT with high surface area and pore volume exhibited exothermic monolayer adsorption of MB. TiNP with low surface area and pore volume yielded a higher adsorption capacity through endothermic multilayer adsorption governed by pore diffusion. TiNP exhibited a higher negative surface charge of 23 mV, compared to 12 mV for TiNT. The adsorption process appears to be an electrostatic interaction, with the cationic dye attracted more strongly to the nanoplates, resulting in a higher adsorption capacity and different adsorption modes. We believe this simple, low cost production of high capacity nanostructured adsorbent material has potential uses in wastewater treatment.
13. Facile preparation of Co3O4 nanoparticles incorporating with highly conductive MXene nanosheets as high-performance anodes for lithium-ion batteries

Author:Zhao, YC;Liu, CG;Yi, RW;Li, ZQ;Chen, YB;Li, YQ;Mitrovic, I;Taylor, S;Chalker, P;Yang, L;Zhao, CZ


Abstract:There is considerable scientific interest in the newly available family of MXenes material. An analog as graphene, this two-dimensional (2D) layered material with the structure of transition metal carbides or nitrides exhibits superior electronic conductivity, large interlayer spacing for highly efficient lithium ions diffusion pathways and environmental benignity, making it useful as energy storage material. However, the inferior capability to store lithium ions impedes its wide application in lithium-ion batteries. Therefore, a facile strategy for preparing Co3O4 nanoparticles incorporated with MXene nanosheets on Ni foams has been developed. Small-size Co3O4 nanoparticles are uniformly distributed within the MXene nanosheets leading to the highly efficient lithium ions and electrons transmission, as well as the prevention for the restacking of MXene nanosheets and huge volume change of the Co3O4 nanoparticles. Under the cooperative effect of Co3O4 nanoparticles and MXene nanosheets, the Co3O4/MXene composite electrode with the mass ratio of Co3O4/MXene = 1:1 exhibits an excellent reversible capacity of 1005 mAh g(-1) after 300 cycles at the current density of 1 C, which significantly exceeds that of pristine Co3O4 electrode. Though the current density climbs to 5 C, the composite electrode remains a stable capacity of 307 mAh g(-1) after 1000 cycles. It is demonstrated that Co3O4/MXene composite electrode has the potential as an anode for the high-performance lithium-ion batteries. (c) 2020 Elsevier Ltd. All rights reserved.
14. Comparisons of switching characteristics between Ti/Al2O3/Pt and TiN/Al2O3/Pt RRAM devices with various compliance currents

Author:Qi, YF;Zhao, CZ;Liu, CG;Fang, YX;He, JH;Luo, T;Yang, L;Zhao, C


Abstract:In this study, the influence of the Ti and TiN top electrodes on the switching behaviors of the Al2O3/Pt resistive random access memory devices with various compliance currents (CCs, 1-15 mA) has been compared. Based on the similar statistical results of the resistive switching (RS) parameters such as V-set/V-reset, R-HRS/R-LRS (measured at 0.10 V) and resistance ratio with various CCs for both devices, the Ti/Al2O3/Pt device differs from the TiN/Al2O3/Pt device mainly in the forming process rather than in the following switching cycles. Apart from the initial isolated state, the Ti/Al2O3/Pt device has the initial intermediate state as well. In addition, its forming voltage is relatively lower. The conduction mechanisms of the ON and OFF state for both devices are demonstrated as ohmic conduction and Frenkel-Poole emission, respectively. Therefore, with the combined modulations of the CCs and the stop voltages, the TiN/Al2O3/Pt device is more stable for nonvolatile memory applications to further improve the RS performance.
15. Organic Amines as Targeting Stabilizer at the Polymer/Fullerene Interface for Polymer:PC61BM Solar Cells

Author:Li, ZR;Yan, LP;Shan, JK;Gu, HM;Lin, Y;Wang, YL;Tan, HW;Ma, CQ


Abstract:Herein, it is demonstrated that a small amount (0.05%% in weight ratio) of polyethyleneimine (PEI) can effectively suppress the "burn-in" degradation of both PTB7-Th:PC61BM and P3HT:PC61BM cells, similar to the piperazine derivatives, suggesting that organic amines can serve as universal stabilizer in polymer:PC61BM solar cells. Light-induced electron spin resonance (LESR) spectroscopy measurement shows a higher ESR signal intensity of PC61BM anions in 0.2%% PEI-doped film than in 1%% piperazine-doped film. Moreover, no piperazine is detected in a 10%% (w/w) piperazine-doped film by gas chromatography-mass spectrometry (GS-MS). These results suggest that the residual piperazine in the blend film is very low, which can be understood by the high volatility of piperazine. Quantum calculations are performed on the intermolecular binding energy (E-B) between polymer (using model repeating units), PC61BM, and piperazine molecules. Results reveal that piperazine prefers to localize at the polymer:fullerene interface by complexing with PC61BM (in P3HT:PC61BM) or PTB7-Th (in PTB7-Th:PC61BM system), which indicates that the photo dimerization of PC61BM which causes the "burn-in" degradation of polymer:fullerene solar cells mainly happens at the donor/acceptor interface, and the organic amine serves as the targeting stabilizer at the interface.
16. Compliance Current Effect on Switching Behavior of Hafnium Oxide based RRAM

Author:Qi, YF;Zhao, C;Fang, YX;Lu, QF;Liu, CG;Yang, L;Zhao, CZ


Abstract:In this study, we compared the basic switching behaviors of HfO2, Al2O3 and HfAlOx (Hf:Al=9:1) based RRAM with Ti top electrode by setting various compliance currents (1mA, 5mA, 10mA, 15mA). The resistance ratio of HfO2 based RRAM (20 -> 320) increases with compliance current whereas it drops not obviously for Al2O3 based RRAM (85 -> 54). HfAlOx (Hf:Al=9:1)) based one has the best resistance ratio (300-440) and resistance stability. All low resistance state (LRS) resistance values of three samples are around 100 Omega with large compliance current while there is a difference in HRS resistance which causes the ratio difference accordingly. The dominant mechanism of resistive switching is the formation and rupture of the conductive filament composed of oxygen vacancies. The appropriate compliance current selection and doping technology to high-k materials should be considered in further study.
17. Neuromorphic Properties of Memristor towards Artificial Intelligence

Author:Zhao, C;Shen, ZJ;Zhou, GY;Zhao, CZ;Yang, L;Man, KL;Lim, EG


Abstract:Recent implementations of memristors have opened up the possibility of making brain-like artificial intelligence neuromorphic computing systems, including highly scalable and low-power neural networks. In fact, it has been demonstrated that a memristors can be implemented as an artificial synapse or as a protruding core of an artificial neuron. This paper reviews the neuromorphic properties of memristors, as well as the similarities of neural computation, synapses, and neurons.
18. Assessment of early triage for acute radiation injury in rat model based on urinary amino acid target analysis

Author:Zhang, YY;Zhou, X;Li, C;Wu, JF;Kuo, JE;Wang, C


Abstract:Rapid radiation injury early triage after a radiological or nuclear exposure is vital for treatment of a large number of wounded people. Owing to the high-throughput analysis and minimally invasive nature of sample collection, radiation metabolomics has been recently applied to radiation damage research. In the present study, exploring the feasibility of estimating the acute radiation injury for early triage by means of urinary amino acid target analysis was attempted using a high performance liquid chromatography electrospray tandem mass spectrometry (HPLC-ESI-MS/MS) technique combined with multivariate statistical analysis. The non-linear kernel partial least squares (KPLS) model was used to separate the control and different radiation dose groups. The classification of different groups was performed after feature selection instead of before feature selection, because of its better separation. The classification accuracy at various radiation injury levels at different time points (5, 24, 48 and 72 h) post-irradiation exposure was investigated. For most of the radiation damage levels, the classification accuracy at 72 h after exposure was superior to that at earlier time points. Additionally, the potential radiation injury biomarkers selected suggested that the urea cycle, glycine, serine and threonine metabolism, alanine, aspartate and glutamine metabolism and related metabolic pathways were involved. The findings suggest that non-invasive urinary biomarkers have great potential for serving as an effective tool for rapid triage of mass casualties in nuclear accidents and understanding the pathogenesis of radiation injury.
19. Tuning photoluminescence of single-layer MoS2 using H2O2

Author:Su, WT;Dou, HL;Li, JW;Huo, DX;Dai, N;Yang, L

Source:RSC ADVANCES,2015,Vol.5

Abstract:Enhancing photoluminescence (PL) of single-layer (1L) MoS2 is critical to its application as the thinnest light-emitting material. In this report, we show that the PL intensity of 1L-MoS2 can be enhanced by 8 times using physisorption of H2O2 molecules as p-type dopants. By using toluene to form the sandwiched structure of H2O2/1L-MoS2/toluene, the PL intensity of 1L-MoS2 can be enhanced up to 27.4 times. Our research proposes a simple but effective method to enhance the light emitting properties of 1L-MoS2.
20. Fabrication of textile based conductometric polyaniline gas sensor

Author:Qi, J;Xu, XX;Liu, XX;Lau, KT


Abstract:In this work, we report the fabrication of gas sensors prepared by in situ polymerization of aniline on non-woven fabrics. It is anticipated that a thin coating of polyaniline film fabricated on porous fabric material would improve the performance of the polyaniline based gas sensor. The hypothesis is based on the recent improved technique that allows the fabrication of nanoparticle based polyaniline film, and the high gas permeability of the fabrics. Sensor fabrication parameters which included acidity of reaction media, precursor and reagent concentrations, and the number of modification cycle have been studied. The resulting gas sensors were found to be highly responsive to a range of volatile organic compounds (VOCs). This high sensitivity was also accompanied with fast response time (similar to 10 s). The order of sensitivity to VOCs was found to be ethanol > chloroform > toluene > acetone > ethyl acetate. Further, the sensor was three orders of magnitude more sensitive to ammonia than all organic vapours tested. (C) 2014 Elsevier B.V. All rights reserved.
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