Methodological Investigation of the Band Gap Determination of Solid Semiconductors via UV/Vis Spectroscopy

Several different evaluation methods (EM) to obtain the band gap energy (Eg) of semiconductors via UV/Vis diffuse reflectance spectroscopy (DRS) are used in literature and no clear consensus which EM use is established. By using P25 as a model semiconductor, evaluating 32 sources our own experiments, we show that determined Eg heavily influenced by (differences up 0.87 eV). For loaded with CuO even contradictive effects metal loading on observed EM. Different phase compositions TiO2 also shown yield EM-dependent results. This paper thus comprehensively investigates most common relevant photocatalyst material classes, illustrates their mathematical graphical determination, gives recommendations method based quantitative indicator pitfalls determining DRS.