Synthesis and optical limiting studies of HAP and HAP@SiO2 core–shell nanoparticles

Abstract

We report the spectral and optical limiting properties of two kinds of HA P nanoparticles (pure HA P and HA P @SiO 2 core-shell nanoparticles) that were wetchemically prepared and coated with silica by means of Stober method. The size, framework substitution and silica coating formation of the resultant particles were confirmed by Transmission Electron Microscopy, X-ray diffraction, Fourier Transform Infrared Spectroscopy and Thermogravimetric analysis. The nonlinear optical limiting properties of HA P and HA P @SiO 2 nanoparticles suspended in ethylene glycol is studied at 532 nm using 5 ns Nd:YAG laser pulses. Observations indicate that effective threephoton absorption is found to be responsible for strong optical limiting characteristics in these nanoparticles and it is seen that the optical nonlinearity is enhanced in coreshell structures as compared with single counterparts. The nonlinear optical parameters calculated from the data show that these materials are efficient optical limiters.

Facile development and structural investigations of HAp and HAp/Ta nanostructures: Photocatalytic activity against Turq blue GL dye

“…HAp peaks are observed to be greatly suppressed and some peaks disappear due to the surface coating of tantalum (Ta) on HAp. Similar effects have been observed by earlier investigators [42][43][44]. Ta has smaller atomic (2.09 Å) and ionic (0.64 Å (Ta 5+ )) radii than Ca which has an atomic radius of 2.23 Å and ionic radius of 1.00 Å [45].…”

“…This also leads to the decreased crystallinity of HAp/Ta. A Similar effect has been observed in silica, Fe 3 O 4 coated HAp core-shell nanoparticles [42,43]. In addition, the preparation of HAp/Ta by using a non-aqueous solvent in an inert atmosphere (Ar atmosphere) helps in the formation of metallic Ta around the HAp core.…”

Nonlinear optical properties of metal nanoparticles: a review

“…The increase in the value of c (3) for the Ag-CdSe hybrid PNC lm as compared to that of the pure CdSe PNC lm may be due to the SPR resulting from the doped silver metal, which largely enhances the local eld near the particle's surface. 110 Wang et al 111 also observed a dramatic increase (eight times) in the n 2 value for Ag/LiNbO 3 as compared to that in pure LiNbO 3 due to the surface plasmon interactions.…”

Oriented and Ordered Biomimetic Remineralization of the Surface of Demineralized Dental Enamel Using HAP@ACP Nanoparticles Guided by Glycine

“…During the phase transformation, the “hard-soft-hard” (HAP-ACP-HAP) connections disappeared and the “hard-hard” (HAPtransferred HAP-HAP) attachment began to dominate in the linear assembly with the guiding effect of glycine31. It is believed that amino acids or proteins could interact with the HAP over the thin ACP layer333435, which explains why Gly can guide HAP@ACP core-shell nanoparticles into oriented and ordered arrays.…”