The Study of Platinum Coated Carbon Nanotubes as Third-Order Nonlinear Optical Materials

Platinum-multiwall carbon nanotubes (Pt-MWCNTs) was prepared through a chemical reduction and was characterized by using UV–Vis Spectrophotometer, Transmission Electron Microscopy (TEM), Field Emission Scanning Electron Microscopy with Energy Dispersive X-Ray (FESEM/EDX) and Raman Spectroscopy. Through this chemical reduction, Pt ions were reduced by the addition of sodium dodecyl sulfate (SDS) and Pt was in-situ deposited on the exterior walls of MWCNTs. TEM and FESEM/EDX analyses have confirmed the presence of Pt on the surface of MWCNTs. From Raman Spectroscopy, the ID/IG of MWCNT is 0.66 while ID/IG of Pt-MWCNT is 0.71, showing that not much defects were resulted by the functionalization of Pt on the surface of MWCNT, while from UV-Vis spectra, Pt-MWCNT is found to absorb at about 265 nm due to the presence of Pt nanoparticles that caused a weak surface plasmon resonance (SPR) absorption in the UV region which will contribute to the NLR measurement. The resulted Pt-MWCNTs was then investigated its third-order nonlinearity response as suspension in water using continuous wave laser and z-scan measurement at 532 nm. Pt-MWCNT displays good transmittance profile and self-defocusing effect with excitation intensity is in order of 10-9 cm2/W. The presence of Pt on the surface of MWCNT has contributed to intrinsic properties and resulted in nonlinear refractive (NLR) effect. Thus, Pt-MWCNT is considered to possess significant third-order nonlinear responses considering its low Pt content and has potential in the development of photonics devices.