Fangming Cui

Highly dispersed Au nanoparticles incorporated mesoporous TiO2 thin films with ultrahigh Au content

Highly dispersed gold nanoparticles (NPs) incorporated mesoporous titania thin films with ultrahigh Au content (53.3 wt%) were synthesized by a deposition-precipitation method using urea as precipitator, which showed high off-resonant third-order optical nonlinear susceptibility (χ(3) = 2.69 × 10−8 esu) measured by the Z-scan technique at 1064 nm. The enhanced χ(3) value of the materials was attributed to the homogeneous dispersion and the ultrahigh concentration of the gold NPs, and the high linear refractive index of the titania matrix.

An easy co-casting method to synthesize mesostructured carbon composites with high magnetic separability and acid resistance

Magnetic mesoporous carbon composites with high surface areas and narrow mesopore size distributions were directly replicated from SBA-15 by a simple co-casting method and the amount of incorporated magnetic particles and saturation magnetization value can be easily tuned by changing the added amount of iron source during synthesis. Furthermore, the magnetic mesoporous carbon composites show good acid resistance due to a carbon shell coating structure around the magnetic particles, which is spontaneously formed during the replication process of the mesoporous carbon composites. The characteristics of the as-synthesized magnetic mesoporous carbon composites were examined by X-ray diffraction, N2 sorption, transmission electron microscopy (TEM), Mossbauer spectroscopy and vibrating-sample magnetometry.

Au nanoparticles incorporated mesoporous silica thin films with a high Au content: preparation and third-order optical non-linearity

Au nanoparticles incorporated in mesoporous silica thin films with a high Au content 29.2 wt% were prepared, which demonstrated a higher off-resonance third-order non-linear optical susceptibility (chi(3)=8.23x10(-10) esu).

Preparation and third-order optical nonlinearity of gold nanoparticles incorporated mesoporous TiO 2 thin films

A kind of Au nanoparticle (NP) containing 2D hexagonal mesoporous TiO2 thin films (MTTFs) has been successfully synthesized through a deposition-precipitation method. The Au NPs show uniform size distribution and the Au content within the MTTFs is measured to be 7.49 wt.%. The third-order nonlinear optical refractive index of the Au NPs contained MTTFs has been measured by the Z-scan technique at 1064 nm. The absolute value of nonlinear refractive index (n2) and third-order nonlinear susceptibility (χ(3)) were calculated to be 2.64×10−7 and 6.32×10−8 esu, respectively. The high nonlinearity of the composite thin films can be attributed to the intraband transition of electrons near the Fermi surface in well-dispersed Au NPs confined in mesoporous channels and the high linear refractive index of the nanocrystalline anatase framework.

Significant third-order optical nonlinearity enhancement of gold nanoparticle incorporated mesoporous silica thin films by magnetic field thermal treatment

Thermal treatments from 600 to 1100 °C with and without 6 T external magnetic fields were applied to the prepared gold nanoparticle (NP) incorporated mesoporous silica thin films (MSTFs). Significantly enhanced third-order optical nonlinear susceptibilities of the thin films thermally treated with the magnetic field were achieved as compared with that of those thermally treated without the magnetic field. The enhancement reached almost one order of magnitude from 700 to 800 °C (i.e. at around the melting point of the gold NPs). The homogeneous dispersion of gold NPs can be maintained up to 1000 °C under the magnetic field compared to the exaggerated growth of gold NPs thermally treated without the magnetic field. The origin for such optical nonlinearity enhancement is discussed.

Magnetic field-induced off-resonance third-order optical nonlinearity of iron oxide nanoparticles incorporated mesoporous silica thin films during heat treatment.

Highly dispersed and uniform Fe(2)O(3) nanoparticles (NPs) have been incorporated into the pore channels of SBA-15 mesoporous silica thin films (MSTFs). And such Fe(2)O(3) NPs incorporated MSTFs did not show detectable nonlinear optical (NLO) signals at off-resonance wavelength 1064 nm by Z-scan technique. However after a vacuum heat treatment at 800 degrees C for 1 h under 6 T magnetic field, the Fe(2)O(3) NPs incorporated MSTFs with very low Fe content (0.8 approximately 1.5 at.%) presented distinctive NLO signals with chi(3) value in an order of 10(-10) esu. We proposed the physical reason for the NLO property generation to be the magnetic domain orientation of the iron oxide NPs incorporated within the pore channels of the MSTFs by the magnetic field heat treatment.