(a) TEM and (b) HRTEM images of silica sol particles aged for 5 hours at room temperature, 25oC; (c) schematic illustration of gel network structure showing the pore and particle sizes (Courtesy from ref. ).
X-ray diffraction (XRD) pattern of SiO2 gel powder at room temperature (~25oC) indicating the amorphous nature of the gel under study. The insets shows the SEM micrographs of SiO2:Eu gels prepared at (a) atmosphere pressure (1 bar) and 50oC; and (b) 120 bars and 150oC, respectively.
XPS survey scan spectra of sputtered and nanoparticles of SiO2:Eu3+ recorded with photon energy of AlKalpha (hv = 1486.6 eV), Inset shows the Si(2P) core level.
Absorbance spectra of Eu doped-SiO2 samples prepared at atmosphere pressure (1 bar) and 120 bars and 150oC, respectively. Inset shows the expanded version of the absorption peaks.
PLE and PL spectra of SiO2:Eu gels made at (a) 50oC, 1 bar and (b) 120 bars and 150oC, respectively. Inset shows the mechanism of Eu3+ transitions.
Nano-Micro Letters, September 2011, Volume 3, Issue 3, pp 146-152
Publication Date (Web): September 1, 2011 (Article)
Schematic illustration of SWNTs strands align on silicon substrate by the shear force of solvent evaporation(a-d): (a) a layer of photoresist resin is coating on the silicon wafer surface, and (b) photoresist resin grooves with rectangular cross section were fabricated by using standard photolithographic methods, then (c) a drop of SWNTs suspension was introduced into the microchannels. As the suspension evaporating, the capillary force can stretch and align carbon nanotubes one by one into a nanoscale strand (d). (e) Mechanism of the SWNTs strands aligning in the mirochannel.
FESEM images of SWNTs aligned in photoresis microchannels after one-time alignment. Some of the SWNTs are difficult to link each other into a continuous strand (identified by write arrow in "b"), and the others are connected one by one (identified by black arrow in "c"). (Magnification a: 6,000; b: 12,000; c: 55,000).
FESEM images of SWNTs strands on substrate with twice process after remove of photoresist resin. Continuous nanoscale diameter SWNTs strands are aligned on the substrate of microchannels uniformly and each SWNT is connected to other end to end. (Magnification a: 6,000; b: 11,000; c: 19,000).
FESEM images of SWNTs strands on substrate with thrice process after remove of photoresist patterns. The SWNTs strands show wider diameter and tangled patterns with some nanotubes attached to the side strands (identified by blank arrow in "a"). (Magnification a: 5,000; b: 11,000).
AFM images (a, c) and the height-distance curves (b, d) of SWNTs strands on the pattern electrodes (a, b: 8 um gap; c, d: 16 um gap).
I-V (a) and Id-Vg curves (b) of the CNTFET device fabricated with aligned SWNTs across two Au electrodes separated by 16 um gap. These SWNTs show a characteristic field effect p-type transistor behaviour.
Publication Date (Web): September 4, 2011 (Article)
SEM images (left column) of copper films deposited on aluminum substrates at (a) -0.2 V, (c) -0.4 V, (e) -0.6 V and (g) -0.8 V for 10 minutes. The SEM images (right column) of the same copper films after electrochemical modification in ethanolic stearic acid solution at 30 V for 30 minutes. The insets of Fig. 1 show the images of water drop on the respective surfaces.
(a) The number density of the copper microdots as a function of deposition potential, and (b) The distance between the copper microdots as a function of deposition potential.
(a) High angle XRD patterns of copper films deposited on aluminum substrates for the duration of 10 min under the application of various potentials followed by electrochemical modification in ethanolic stearic acid solution; (b) low angle XRD patterns of (a). CuSA is the XRD pattern of copper stearate films as reported by us in .
(a) The variation of roughness vs. deposition potential; (b) variation of water contact angle vs. surface roughness on the stearic acid modified copper film deposited on aluminum surfaces. The inset of (a) shows the 3D images of the rough surfaces and (b) shows the images of water drops (-0.2 V and -0.8 V).
Publication Date (Web): September 22, 2011 (Article)
Representative SEM (A) and HR-TEM image (B) of 1 wt% Au/BiVO4 and the corresponding magnified views of Au nanocrystalline (C).
(A) UV-vis reflectance spectra of BiVO4 and Au/BiVO4 and (B) Au LIII edge XANES spectra for the 1wt% Au/BiVO4 before (a) and after photocatalytic reaction (b), in comparison with those for the references Au foil (c) and Au2O3 (d), the curves were offset vertically.
The decrease of phenol by different photocatalysts as a function of visible light irradiation time (λ>400 nm or λ>535 nm).
Current density-potential curves of BiVO4 (A) and 1wt% Au/BiVO4 (B) in 0.5 M Na2SO4 solution.
Photocurrent transients of (A) 1wt% Au/BiVO4 electrode under various illumination conditions at -0.4 V vs. Ag/AgCl bias and (B) Au/BiVO4 electrodes with various Au contents under λ>600 nm illumination at 0.2 V vs. Ag/AgCl bias.
Simplified scheme of the primary processes occurring upon excitation of an Au/BiVO4 electrode. (A: bias>-0.34 V; B: λ<535nm, bias<-0.34 V; C: λ>535 nm).
Publication Date (Web): September 27, 2011 (Article)
(a) Initial reaction mixture containing extract of Cymbopogan citratus leaves and 1 mM silver nitrate in 1:4 ratio; (b) Color change of reaction mixture after adjusting pH 8.0; (c) Color change of reaction mixture after microwave irradiation.
UV-visible spectrophotometer analysis of silver nanoparticles synthesized using extract of fresh Cymbopogan citratus (Lemongrass) leaves.
Frequency size distribution graph of silver nanoparticles synthesized using extract of fresh Cymbopogan citratus (Lemongrass) leaves; X axis: particles size (nm), Y axis: concentration/ml × 106.
TEM micrograph of silver nanoparticles synthesized using extract of Lemongrass fresh leaves.
EDX spectra of silver nanoparticles solution.
Effect of silver nanoparticles synthesized using Cymbopogan citratus (Lemongrass) leaves extract on various microorganisms.
Effect of silver nanoparticles synthesized using extract of Cymbopogan citratus (Lemongrass) leaves on bacteria and fungi.
(a) Light-current-voltage characteristics of In0.27Ga0.73N/GaN QD laser measured in the pulsed bias mode at T = 278 K; (b) electroluminescence spectra of QD laser below (with dc bias) and above (with pulsed bias) threshold. Inset shows measured variation in spectral output peak wavelength with injection current (from Ref. ).
Photographs of the light emitted at RT from GaN/AlN QDs on Si(111) excited by a 10 mW unfocused HeCd laser (~0.3 W/cm2) (from Ref. ).
(a) Schematic structure for the blue LED with InGaN/GaN MQDs; (b) I–V characteristics of the MQD LED. the forward voltage is 3.1 V at 20 mA injection current; (c) Dominated wavelength of EL spectra as a function of injection current for the MQD LED and conventional MQW LEDs (see Ref. [43,44]for details).
The proposed cubic shaped GaN QD within a large Al0.2Ga0.8N QD (from Ref. ).
(a) The p-i-n QD SC structure with different sized QDs in each layer; (b) Energy-band diagram of p-i-n QD SC and generation-recombination processes in QDs for one type of carriers. Depletion layers in p and n layers are neglected (from Ref. ).