Mn-doped molybdenum trioxide for photocatalysis and solar cell applications

Abstract Mn-doped MoO3 with different compositions in powder and thin film form have been prepared. The Orthorhombic (α-MoO3) crystal structure of pure MoO3 was revealed for (Mn)x(MoO3)1-x powdered samples, while the as-deposited films manifested an amorphous structure. FTIR spectra ensured that bonds are belonging to the vibrations of Mo O bonds to Mo–O–Mo stretching vibrations at the optimum peaks, confirming the presence of a single phase of MoO3. For powdered samples, the intensity of reflection has reached the maximum value (up to ≈ 85%) for (Mn)x(MoO3)1-x sample with x = 0.02 at.%, whereas the minimum value of reflection was obtained for undoped and (Mn)x(MoO3)1-x sample with x = 0.10 at.%. For thin films, the intensity of reflectance varies from 10% to 25% for all the samples. The optical energy was found to vary from 3.20 eV to 3.33 eV for the powdered samples and from 3.11 to 3.66 for as-deposited thin films. The photocatalytic properties were studied for all powdered samples by determining the absorbance of Methylene blue, using UV source as a function of illumination time. The degradation efficiency had maximum value of 48.5% at x = 0.10 at.%. The electrical conductivity study exhibited that, the maximum electrical conductivity of 3.11 × 102 (Ω m)−1 was obtained for the sample x = 0.10 at.%. It was a good match with the high degradation efficiency, minimum value of absorption, and narrow bandgap that existed due to the formation of the intermediate state of Mn.