Doping charge transfer in Pt/CNT systems induced by laser power heating

Abstract

Pt nanoparticles were dispersed on bamboo-like multiwall carbon nanotubes (Pt/CNTs). Raman Scattering effects were evaluated using distinct excitation laser powers e.g., from 1.0 to 6.0 mW over the Pt/CNTs. The charge transfer for the doping mechanism was investigated by Raman scattering and theoretical calculations. The sample was characterized via transmission electron microscopy and resonant Raman spectroscopy. The positions and widths of Raman G, G′-bands were analyzed based in the deconvolution of the bands. The laser power was varied from 1 to 4 mW closely related to the local temperature of 460, 540 and 500 K, respectively. This corresponded to the computed to Ginner and Gouter components displacements to low frequencies of ca. 20 and 15 cm−1. The results suggested a dependence of the laser power heating effect on the properties of the Pt/CNTs. Considerations about the destruction of walls surrounding particles are taken into account based on these results. Also, electron transfer to the MWCNTs with increase of the variation laser power was observed. Theoretical approaches for the intercalation stages of Pt on MWCNT were performed to verify the density of electronic states. The results indicated that the system exhibited a metallic behavior without Pt nanoparticle and stage 1 (stg #1), which show indeed energies gap is due to presence of Pt, and other stages is according with the experimental data.