Photoluminescence properties of polymethyl methacrylate-coated Zn2SnO4 nanowires

Polymethyl methacrylate (PMMA)-coated Zn2SnO4 nanowires were synthesized by a two-step process: thermal evaporation of a mixture of Zn and Sn powders at 700 °C in an oxidizing atmosphere followed by spin coating of PMMA solution. The nanowires were 30-80 nm in diameter and up to a few hundred of micrometers in length. Photoluminescence showed that the near-band edge (NBE) emission-to-visible emission ratio of Zn2SnO4 was enhanced significantly by PMMA coating. The highest NBE emission-to-visible emission ratio was obtained at a PMMA concentration of 0.25 mM. INBE/IDL was increased almost 10 times by coating the nanowires with 0.25-mM PMMA. The enhanced NBE emission and suppressed visible emission might be due to enhanced excitonic emission efficiency.