Surface functionalization-enhanced magnetism in SnO2 nanoparticles and its correlation to photoluminescence properties

Abstract

A high value of magnetic moment of 0.08 emu g⁻¹ at room temperature for SnO₂ nanoparticles (NPs) was observed. Surface functionalization with octadecyltrichlorosilane (OTS) enhanced the saturation magnetic moment of NPs to an anomalously high value of 0.187 emu g⁻¹ by altering the electronic configuration on the NPs surface. Surface functionalization also suppressed photoluminescence (PL) peaks arising from oxygen defects around 2 eV and caused an increase in the intensities of two peaks near the violet region (2.6–3 eV). PL studies under a uniform external magnetic field enriched the understanding of the role of OTS. Both OTS and external magnetic fields significantly modulated the luminescence spectra by altering the surface electronic structure of NPs. Extra spins on the surface of SnO₂ NPs created by the surface functionalization process and their influence on resultant magnetic moment and luminescence properties are discussed in detail.