Enhancement of visible-light-driven photoresponse of Mn-doped SnO2 quantum dots obtained by rapid and energy efficient synthesis

Abstract

Mn-doped SnO2 quantum dots (QDs) with different Mn concentrations were prepared by solution combustion synthesis. The crystallite size was under 5 nm was confirmed from XRD and HR-TEM. A considerable decrease in band gap energy was observed with the increase in Mn content. The PL spectra show orange emission at about 590 nm due to the ultra-small crystallite size and crystal defects of SnO2 QDs. The photocatalytic degradation of MO dye was measured under visible light irradiation using the Mn-doped SnO2 QDs as catalysts. 3 mol% Mn-doped SnO2 QDs showed the 17 times higher photocatalytic performance than SnO2 QDs within 240 min.