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Guai G.H.,Nanyang Technological University | Guai G.H.,Globalfoundries | Li Y.,Nanyang Technological University | Ng C.M.,Globalfoundries | And 4 more authors.
ChemPhysChem | Year: 2012

Different types of single-walled carbon nanotubes (SWCNTs), pristine (p-), metallic (m-) and semiconducting (s-) are incorporated into TiO 2 photoanodes to improve the dye-sensitized solar-cell (DSSC) performance and their effects on the device performance are further investigated. Although all three types of SWCNTs are found to have comparable structural morphologies and a reduced charge transport resistivity for the photoanodes, only the semiconducting one was able to suppress charge-recombination events, resulting in even greater improvement of DSSC performances. This is very likely to be ascribed to the higher energy barrier of s-SWCNTs compared to both m- and p-SWCNTs to block the back flowing of dye-injected electrons for I 3 - reduction in the charge recombination process. Photoanodes based on TiO 2 with either pristine (p-), metallic (m-), or semiconducting (s-) single-walled carbon nanotubes (SWCNTs) are prepared and characterized. The mobility of s-SWCNTs and their suppression of charge recombination towards I 3 - redox species (see picture) allow a more positive synergistic influence over the charge separation/ collection within TiO 2 films while p- and m-SWCNTs tend to accelerate charge recombinations. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Yuan W.,Southwest University | Lu Z.,Southwest University | Lu Z.,Chongqing Key Laboratory for Advanced Materials and Technologies of Clean Electrical Power Sources | Wang H.,Nanyang Technological University | And 2 more authors.
Physical Chemistry Chemical Physics | Year: 2013

Great challenges still remain to assemble metal nanoparticles on a substrate with tunability, high density, robust stability, good dispersion and well-retained properties for various applications. Herein a new concept using a polymer thin-film as a sacrificial template is investigated to fabricate highly dense and well-dispersed nanoparticle arrays. In contrast to a conventional "hard" template, the polymer template is a porous multilayered film allowing in situ growth of Au nanoparticles with a restricted ripening mode, and tuning the nanoparticle size and density of the arrays is possible by simply adjusting the loading conditions. The prepared substrate-attached nanoparticle arrays demonstrate good thermal and chemical stability, while offering highly sensitive and tunable localized surface plasmon resonance (LSPR) refractive index sensing with a broad linear dynamic range. This method could be extended to controllably fabricate other robust and "clean" nanoparticle arrays on various substrates for various applications including sensing, catalysis and optoelectronics. This journal is © 2013 the Owner Societies.


Chen T.,Nanyang Technological University | Chen T.,Chinese University of Hong Kong | Hu W.,Nanyang Technological University | Hu W.,Southwest University | And 6 more authors.
Advanced Functional Materials | Year: 2012

The microstructures of photoa and countera electrodes play critical roles in the performance of dyea sensitized solar cells (DSSCs). In particular, various interfaces, such as fluorinateda tin oxide (FTO)/TiO2, TiO2/TiO2, and TiO2/electrolyte, in DSSCs significantly affect the final power conversion efficiency (PCE). However, research has generally focused more on the design of various nanostructured semiconducting materials with emphasis on optimizing chemical or/and physical properties, and less on these interface functionalizations for performance improvement. This work explores a new application of graphene to modify the interface of FTO/TiO2 to suppress charge recombination. In combination with interfaces functionalization of TiO2/TiO2 for low chargea transport resistance and high chargea transfer rate, the final PCE of DSSC is remarkably improved from 5.80% to 8.13%, achieving the highest efficiency in comparison to reported graphene/TiO2-based DSSCs. The method of using graphene to functionalize the surface of FTO substrate provides a better alternative method to the conventional prea treatment through hydrolyzing TiCl4 and an approach to reduce the adverse effect of microstructural defect of conducting glass substrate for electronic devices. Graphene is found to suppress carrier recombination occurring on fluorinated tin oxide (FTO) surfaces and at FTO/TiO2 interfaces in dyea sensitized solar cells. With a graphene interlayer between FTO and TiO2, the device efficiency can be increased by 40% when compared with those using solely TiO2 as an anode material. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Zheng X.T.,Southwest University | Zheng X.T.,Nanyang Technological University | Zheng X.T.,Chongqing Key Laboratory for Advanced Materials and Technologies of Clean Electrical Power Sources | Chen P.,Nanyang Technological University | And 3 more authors.
Small | Year: 2012

Subcellular-targeted drug delivery has much potential to defeat infectious diseases and cancers. Medical and/or biochemical effects of drugs/bioactive molecules delivered to subcellular compartments and their subcellular sites of action need to be investigated but have not been explored. Here the subcellular location-dependent biochemical responses of a potent anticancer drug, β-lapachone (β-lap), is investigated by a reduced graphene oxide (rGO)-functionalized optical nanoprobe, which can deliver and simultaneously monitor the drug effects at nanoscales. For the first time, distinct oxidative responses and calcium alterations in three selected subcellular domains are observed and clearly pinpoint that the perinuclear region is the optimal subcellular site for β-lap to have the best anticancer efficacy. The results presented here provide not only scientific insights of subcellular drug-cell interaction that is not obtainable from conventional methods, but they also provide valuable knowledge for rational design of subcellular-targeted delivery or spatially resolved signal intervention. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Guo C.X.,Southwest University | Guo C.X.,Nanyang Technological University | Shen Y.Q.,Nanyang Technological University | Dong Z.L.,Nanyang Technological University | And 5 more authors.
Energy and Environmental Science | Year: 2012

Through the PO4 3- groups regularly arranged on its sugar-phosphate backbone, DNA is used to direct the growth of a network structure of ultrasmall FePO4 nanoparticles on double-wall carbon nanotubes. The resulting structure has achieved nearly 100% theoretical storage capacity for the FePO4 active component as a cathode in lithium-ion batteries. © 2012 The Royal Society of Chemistry.

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