Final answer:
To calculate the refractive index of a TiO2 deposited thin film, measurements of absorbance, reflectance, and transmittance are used. The Swanepoel method is one approach to determine the refractive index using these data. Additionally, for a given absorbance of 1.0, percent transmittance can be calculated using the relationship A = -log10(T%), resulting in 10% transmittance.
Step-by-step explanation:
To calculate the refractive index (n) of a TiO2 deposited thin film from absorbance (Abs), reflectance (R%), and transmittance (T%) data gathered using a UV-Vis spectrophotometer, you can use the relationship between absorbance, reflectance, and transmittance.
With the simplified assumption that absorbance + reflectance + transmittance = 1 (or 100%), you can calculate the absorbance at a wavelength using the formula A = log10(Io/I), where Io is the intensity before the sample and I is the intensity after the sample.
To solve for refractive index using these measurements, you may employ the Swanepoel method, which is a more complex but accurate technique used to determine the refractive index of thin films.
This method involves using the transmittance spectrum to compute the envelope curves of the maxima and minima and applying the Fresnel equations. Alternatively, if you know the thickness of the thin film, other methods like the envelope method can be employed.
However, applying these techniques is beyond basic principles and commonly requires specialized knowledge and software for accurate measurements and interpretations.
For Exercise 4.11: To express an absorbance (A) of 1.0 in terms of percent transmittance (%T), we use the equation A = -log10(T%). If A = 1.0, then T% can be found by rearranging the equation to T% = 10-A, which yields T% = 10-1 or 10% transmittance.