Fuel-dependent, shape-selective, distinct blue and green photoluminescence from α-Bi2O3 and β-Bi2O3 synthesised using microwave combustion

In the current study, α-Bi2O3 and β-Bi2O3 were synthesised using a one-step, novel, solid–solid combustion technique. The reaction rate was increased with the use of microwaves (molecular heating) compared to direct or indirect heating. A strong relationship was observed between the fuel, polymorphic structure, shape and optical properties of the synthesised Bi2O3. Photoluminescence studies reveal that two major visible emissions are observed for all samples. The two emissions are distinct with a broad peak in blue and a narrow peak in green. The intensity of the green characteristic emission depends strongly on the heating method used for synthesis and is more intense for microwave-synthesised samples.