The authors of the discussed article [1] have determined the reflectance spectra via the relation [1]. For this purpose, they have used the measured values of T and derived values of A via equation [1]. However. It must be noted that the derived values of R using this method are unreasonable since the results of the latter relation which has been presented by Beer and Lambert are not the percent values of the absorbance. (Ia is the absorbed intensity of the electromagnetic radiation by the specimen) [2], [3], [4], [5]. To verify my assertion, I have fabricated some nickel oxide thin films using the spray pyrolysis technique and measured the transmittance and reflectance spectra of the sample (the measurement has been done using a UV–Vis-NIR spectrophotometer equipped with a reflectance accessory, Model: Perkin Elmer Lambda 9). Also, I have calculated the absorbance and reflectance spectra using the presented method in the original paper. As shown in Fig. 1, the measured and calculated values of R are significantly different. If one wants to find the reflectance, he/she must measure it.

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