Attached is a document containing the spectra of two materials prepared differently. The materials are a composite of kaolinite clay + biomass + ZnCl2 + NaOH calcined in microwave oven for 5 mins (figure 1) and kaolinite clay + biomass + ZnCl2 + CuCl2 + NaOH calcined at 500 oC under a nitrogen atmosphere for 2 h (figure 2). The XRD spectra results shows the presence of ZnO and CuO phases in the nanocomposites
Given the multiple peaks in the spectra we are not sure which peak is relevant in calculating for the bandgap of these materials. We will be grateful for any advice in interpreting the spectra and calculating the bandgaps of the materials.
The following paper reported interpretation of UV-Vis spectra of Co3O4/SiO2 nanocomposites and show its band gap calculations
Article Structural, optical and electrical properties of sol–gel pre...
Band gap of the samples has been calculated for total spectra would given a accurate band gap value rather than particular peak position. That has been possible by absorption coefficient not by reflectance. So..first please convert your reflectance spectra into absorption by using Kubelka-Munk function, F(Ra) (equivalent to the absorption). Then find out hv in turn convert it into hv eV. Multiply Kubelka-Munk function and hv eV. If you want to find out direct band gap square, F(Ra)hv]2 . otherwise indirect band gap take square root F(Ra)hv]1/2.
Please see the paper (DOI:10.1021/acs.jpcc.6b09082)
Thank you,
Well Regards,
Divya Arumugam.
The following paper reported interpretation of UV-Vis spectra of Co3O4/SiO2 nanocomposites and show its band gap calculations
Article Structural, optical and electrical properties of sol–gel pre...
Unfortunately your data seems to be confusing. What have you measured.
uv-vis is usually relative to wavelength not wave numbers. This might be a typo, but an increase in transparency towards 200 nm ?
additionally it might be possible that you monitored the light source of you equipment.
Bandgaps of ZnO are clearly montorabe.
Article Synthesis and testing of ZnO nanoparticles for photo-initiat...
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