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Zhang F.,Institute of Functional Nano and Soft Materials FUNSOM | Sun B.,Institute of Functional Nano and Soft Materials FUNSOM | Song T.,Institute of Functional Nano and Soft Materials FUNSOM | Zhu X.,Soochow University of China | Lee S.,City University of Hong Kong
Chemistry of Materials | Year: 2011

Efficient, stable hybrid photovoltaic (PV) devices based on poly(3-hexylthiophene) (P3HT) and silicon nanowire arrays (SiNWs) are reported. A two-step, chlorination/methylation procedure is used to convert Si-H bonds into Si-C ones to reduce the velocity of charge recombination at the silicon surface as well as achieve a favorable alignment of band-edge energies. In addition, Pt nanodots (PtNDs) are deposited onto the surface of the SiNWs to further tune the band-edge alignment and passivate nonmethylated silicon sites. Methylated silicon surfaces modified with PtNDs possess a favorable internal electric field in accord with expectations based on the electron affinity (∼3.7 eV) and net positive surface dipole measured on such surfaces by ultraviolet photoemission spectroscopy. This attests to the degree of chemical control that can be exerted over the internal electric field in such systems by surface functionalization. In concert with methyl termination and decoration with PtNDs, hybrid PV devices based on composites of SiNWs and P3HT achieve an external quantum efficiency (EQE) of 76% at 800 nm and a power conversion efficiency (PCE) of 5.9% under simulated air mass 1.5 solar irradiation at 100 mW cm-2. Moreover, these devices exhibit stable performance for more than 1200 h. In contrast, devices based on composites of hydrogen-terminated planar silicon and P3HT display an EQE of 0.19% at 560 nm and PCE of 0.006%. The ∼800 times enhancement in device performance and improvement in stability are assigned to the facile derivatization of the surface of silicon nanostructures. © 2011 American Chemical Society. Source


Tao H.,Institute of Functional Nano and Soft Materials FUNSOM | Ma S.,Soochow University of China | Guo W.,Institute of Functional Nano and Soft Materials FUNSOM | Liu H.,Soochow University of China | Liu Z.,Institute of Functional Nano and Soft Materials FUNSOM
Biomacromolecules | Year: 2011

Novel poly(ethylene oxide)-graft-doxorubicin (PEO-g-DOX) prodrugs with DOX covalently conjugated to PEO via a pH-sensitive hydrazone bond were developed. PEO-g-DOX conjugates could be readily prepared in the following steps: (i) anionic ring-opening copolymerization of ethylene oxide (EO) and allyl glycidyl ether (AGE) afforded functional PEO with controlled molecular weights, low polydispersities, and multiple pendant double bonds (PEO-g-allyl); (ii) conjugation of PEO-g-allyl with methyl mercaptoacetate, followed by treating with hydrazine hydrate, quantitatively transformed allyl into hydrazide groups (PEO-g-hydrazide); and (iii) DOX was covalently immobilized to PEO-g-hydrazide via acid-labile hydrazone bonds (PEO-g-DOX). Here on the basis of PEO-g-allyl4.4 (Mn?GPC = 22?400, PDI = 1.19) and PEO-g-allyl7.1 (Mn?GPC = 15?300, PDI = 1.16, the subscription refers to number of allyl groups per chain) two freely water-soluble PEO-g-DOX prodrugs with 2.9 and 3.6 DOX per molecule (denoted as PEO-g-DOX2.9 and PEO-g-DOX3.6, corresponding to drug loading content of 5.6 and 9.0 wt %, respectively) were obtained. The in vitro release studies confirmed much faster release of DOX at pH 5.0 and 6.0 than at pH 7.4. For example, approximately 16, 52, and 61% of drug were released in 22 h, and 23, 83, and 92% of drug were released in 120 h from PEO-g-DOX 2.9 at pH 7.4, 6.0 and 5.0, respectively. Notably, confocal laser scanning microscope (CLSM) observations revealed that DOX was released and delivered into the nuclei of RAW 264.7 cells following 24 h of incubation. MTT assays demonstrated that PEO-g-DOX2.9 had pronounced cytotoxic effects to RAW 264.7, HeLa, and 4T1 breast tumor cells with IC50 values of about 26.5, 42.5, and 32.0 μg DOX equiv/mL, whereas the corresponding polymer carrier PEO-g-hydrazide4.4 was nontoxic. The In Vivo pharmacokinetics and biodistribution studies in mice showed that PEO-g-DOX2.9 prodrugs had significantly prolonged circulation time and enhanced drug accumulation in the tumor as compared with free DOX. We are convinced that endosomal pH-activatable PEO-g-DOX prodrugs have tremendous potential for targeted cancer therapy. © 2011 American Chemical Society. Source


Liu L.,Institute of Functional Nano and Soft Materials FUNSOM | Liu M.,Institute of Functional Nano and Soft Materials FUNSOM | Su Y.,Institute of Functional Nano and Soft Materials FUNSOM | Dong Y.,Institute of Functional Nano and Soft Materials FUNSOM | And 5 more authors.
Nanoscale | Year: 2015

We describe a polymer-based artificial tadpole-like micromotor, which is fabricated through the electrospinning technique. By incorporating functional materials onto its surface or within its body, the resulting tadpole-like micromotor can not only move autonomously in an aqueous solution with a flexible tail, but also exhibit thermo- and magnetic responsive properties. © The Royal Society of Chemistry 2015. Source


Zhao Y.,Institute of Functional Nano and Soft Materials FUNSOM | Zhao Y.,Soochow University of China | Yang D.,Institute of Functional Nano and Soft Materials FUNSOM | Yang D.,Soochow University of China | And 12 more authors.
Surface Science | Year: 2016

In this paper, we present a simple method to synthesize eccentric Au@SiO2 Janus nanoparticles. By simply tuning the concentration of poly(vinyl pyrrolidone) (PVP), the surface of gold nanoparticle can be partially or fully wrapped with the amphiphilic ligand. As a result, Janus nanoparticle or concentric core-shell nanostructures can be obtained, respectively. A systematic study has been carried out to confirm the function of PVP molecules. The as-prepared Janus nanoparticle can act as a catalyst to catalyze the reduction of 4-nitrophenol, while the core-shell nanostructure is not active due to the coverage of dense silica shell. This work provides a robust and scalable method to produce Au@SiO2 Janus nanoparticles. © 2015 Elsevier B.V. All rights reserved. Source


Liu J.,Institute of Functional Nano and Soft Materials FUNSOM | Liu J.,Soochow University of China | Zhang H.,Institute of Functional Nano and Soft Materials FUNSOM | Zhang H.,Soochow University of China | And 13 more authors.
ChemCatChem | Year: 2014

The design of photocatalysts for overall water splitting in visible light remains a huge challenge. Carbon quantum dots (CQDs)/Ag/Ag3PW12O40 nanocomposites have high photocatalytic activities for overall water splitting in visible light without electron acceptors or hole scavengers. In the present system, H2 evolution was performed on Ag particles. O2 evolution appears to be a result of the oxidation of H2O on the valence band of Ag3PW12O40, which is enhanced by promoted electron-transfer events at hybrid interfaces of the polyoxometalates and CQDs. The synergistic effects of CQDs, Ag, and Ag3PW12O40 enable the design of a water-splitting catalyst with a remarkably improved efficiency (with an active region of λ<650 nm; apparent quantum yield ≈4.9% at 480 nm) and operational stability. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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