Energy band structure investigation of blue and green light emitting Mg doped SnO2 nanostructures synthesized by combustion method

Tin oxide (SnO2) and Mg doped (2, 4, 6, and 8wt%) SnO2 nanoparticles were synthesized by the self-propagating solution combustion synthesis using citric acid as fuel. The characterization of samples was done by X-ray diffraction spectroscopy (XRD), transmission electron microscopy (TEM), UV–visible spectroscopy, SAED and photoluminescence (PL). XRD pattern and TEM studies show that the synthesized particles are of average size 30nm and they are in tetragonal rutile structure of SnO2. Combined blue and green emission is seen in 4wt% Mg doped SnO2 and intensity of blue band is increased with respect to increase in Mg dopant concentration which is attributed to increase in population of oxygen vacancies. The PL emission in blue and green region is due to the doubly charged state (Vo2+) of oxygen and tin interstitial defects respectively and is explained with an energy band diagram. •The optical properties of tin oxide nanostructures can be modified by adding Magnesium salts in combustion synthesize process.•Combined blue and green emission observed in 4wt% Mg doped SnO2 is contributed to oxygen vacancies and tin interstitials.•Population of oxygen vacancies are increased with Mg dopant concentration, which will boost the intensity of blue emission in SnO2.•The 4wt% Mg doped SnO2 can be used for electron injection in heterojunction LEDs for generating white light.