Ramifications of chromium-to-bismuth ions substitution on the structural and optical characteristics of bismuth borate glasses for optoelectronic applications

The exploration of optoelectronicmaterialswith distinctive properties is still ongoing. To this end, a
series of quaternary glassymaterials of the composition 15Na2O–65B2O3–(20–x)Bi2O3–xCr2O3,
denoted asNBBC, is synthesized using themelt quenchingmethod,where x=0.0, 2.0, 4.0, 6.0, 8.0,
and 10.0mol%.X-ray diffraction (XRD) confirms that the glasses under investigation are amorphous,
except for the samplewith amolar ratio of 10%Cr2O3,which showed a polycrystalline structure. FTIR
analysis of theNBBCglasses reveals structural changes affecting Bi-Oand B-Ovibrations, suggesting a
correlation between composition and optical properties. Interestingly, the bandgap energy of the
NBBCglasses, determined optically, demonstrates a reduction from2.881 eVto 1.941 eVwith
increasing Cr2O3 content.Conversely, the tail energy exhibits an opposite trend. The observed
reduction in the bandgapwith increasing Cr-ions is attributed to the introduction of chromiumin the
glassymatrix,which changes the electronic structure and enhances the light absorption efficiency.
Furthermore, various optical parameters are calculated, such as the optical constants, dielectric
constants, loss energy, the density of coverage, sheet resistance, the figure ofmerit factor, and
dispersion parameters.Notably, all of these parameters demonstrate a remarkable sensitivity to the
gradual increment of chromiumions. These findings imply that theNBBCglasses could be
appropriate for optoelectronic purposes.