Noncovalently Modified Carbon Nanotubes with Carboxymethylated Chitosan: A Controllable Donor-Acceptor Nanohybrid

We report here the modification of multiwalled carbon nanotubes (MWNTs) with a kind of polysaccharide, carboxymethylated chitosan (cmCs), and their potential usage as donor-acceptor nanohybrids. The modified composites (cmCs/MWNTs) were characterized by high-resolution TEM, FT-IR, TGA and time-resolved spectroscopy. The time-resolved spectroscopic experiments revealed that interfacial electron transfer readily takes place between MWNTs and surface immobilized cmCs chains. The forward electron transfer is fast (< 20 ns) while the backward recombination is slow. The recombination process strongly depends on the chain length of carboxylmethylated chitosan, i.e. a shorter recombination lifetime (~1.1 μs) for the shorter-chain cmCs coated MWNTs against that of the longer-chain cmCs coated MWNTs (~3.5 μs). The results demonstrated that the cmCs/MWNTs composite may be applied as a controllable donor-acceptor nanohybrid

International Journal of Molecular Sciences

Laser photolysis study of anthraquinone in binary mixtures of ionic liquid [bmim][PF6] and organic solven

Laser photolysis study of anthraquinone in binary mixtures ofionic liquid [bmim][PF6] and organic solvent

Photochemical properties of the ionic liquid (RTIL) 1-butyl-3-methylimidazoliumhexafluorophosphate [bmim][PF6] and its binary mixed solutions with organic solvent(DMF and MeCN) were investigated by laser photolysis at an excitation wavelength of 355nm, using anthraquinone (AQ) as a probe molecule. It was indicated that the triplet excitedstate of AQ (3AQ*) can abstract hydrogen from [bmim][PF6]. Moreover, along with thechange of the ratio of RTIL and organic solvent, the reaction rate constant changes regularly.Critical points were observed at volume fraction VRTIL = 0.2 for RTIL/MeCN and VRTIL =0.05 for RTIL/DMF. For both systems, before the critical point, the rate constant increasesrapidly with increasing VRTIL; however, it decreases obviously with VRTIL after the criticalpoint. We conclude that the concentration dependence is dominant at lower VRTIL, while theviscosity and phase transformation are dominant at higher VRTIL for the effect of ionic liquidon the decay of rate constant

High Photoresponse Black Phosphorus TFTs Capping with Transparent Hexagonal Boron Nitride

Black phosphorus (BP), a single elemental two-dimensional (2D) material with a sizable band gap, meets several critical material requirements in the development of future nanoelectronic applications. This work reports the ambipolar characteristics of few-layer BP, induced using 2D transparent hexagonal boron nitride (h-BN) capping. The 2D h-BN capping have several advantages over conventional Al2O3 capping in flexible and transparent 2D device applications. The h-BN capping technique was used to achieve an electron mobility in the BP devices of 73 cm2V&minus;1s&minus;1, thereby demonstrating n-type behavior. The ambipolar BP devices exhibited ultrafast photodetector behavior with a very high photoresponsivity of 1980 mA/W over the ultraviolet (UV), visible, and infrared (IR) spectral ranges. The h-BN capping process offers a feasible approach to fabricating n-type behavior BP semiconductors and high photoresponse BP photodetectors