SERS study of Co-doped TiO₂ nanoparticles

Abstract

Single-phase Co-doped TiO₂(Co _xTi_1−xO₂) nanoparticles(NPs) synthesized via a simple sol-hydrothermal method were used as surface-enhanced Raman scattering(SERS) substrates. Interestingly, it was found that SERS signals were enhanced greatly compared to those of pure TiO₂ nanoparticles when an amount of Co²⁺ ions were doped into the TiO₂ lattice. Detailed results clearly show that Co element as Co²⁺ was incorporated into the TiO₂ lattice and the defects were created due to the substitution of Co²⁺ ions for the Ti⁴⁺ ions. The Co²⁺ doping increases the defect concentration of Co _xTi_1−xO₂ NPs. An amount of defects is beneficial to the charge-transfer so as to increase the SERS activities. A possible mechanism of charge-transfer from Co _xTi_1−xO₂ NPs to molecules was then briefly discussed.

Keywords

TiO₂ / Dope / Defect / Surface-enhanced Raman scattering / Charge-transfer

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