Effect of crystallite size, Raman surface modes and surface basicity on the gas sensing behavior of terbium-doped SnO2 nanoparticles

In the present work, we report the structural, optical and gas sensing properties of Tb3+-doped SnO2 nanoparticles. XRD results confirmed tetragonal rutile structure of both undoped and Tb3+-doped SnO2 nanoparticles which was further confirmed from Raman results. The increase of dopant concentration resulted in decrease in crystallite size which has been confirmed from XRD and TEM results. Raman spectra exhibited bands positioned at 562 and 487 cm(-1) whose contribution has been found to increase with decrease in crystallite size. The shifting and broadening of Raman active bands has been explained by well-known phonon confinement model. EDS analysis inveterate presence of terbium in the doped SnO2 nanoparticles. It has been observed that 3% doped samples exhibited optimum sensor response towards ethanol vapor. The optimum operable temperature of doped samples has been reduced as compared to undoped samples. The enhanced sensor response of doped nanoparticles is attributed to the small crystallite size, high surface basicity and enhanced contribution of Raman surface vibration modes of nanoparticles. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.