Instrument: UV-vis-NIR spectrophotometer (Cary 5000, Agilent) (DRA accessory used)
Sample: Textrued PDMS thin film on glass
Reference: Air
Air has 100% transmittance in all wavelength ranges.
Total transmittance of textured PDMS film is too high in UV range (over 100%).
Dear colleague
try to verify if you have already substract the noise from the transmitted signal (if any) or provide more details one can halp you
regards
Dear Seongkuk Seo,
It looks like your baseline is not correct! Could you please run the baseline without any samples in any beams (reference arm and sample arm)? Then run the system only air to see the baseline whether it is 100%?
It should be. Then run your sample at the sample beam to see what happens. It should give less than 100%. Please let me know. Otherwise the aperature problem.
The signals are very noisy. The light source of the instrument might be dead. Perform a self-check of the instrument
@Xuhua Wang, After running the baseline without sample, it came out correctly at 100% when run only with air. but the transmittance of sample in UV region is still over 100%.
Result of other sample is correct. but only textured PDMS sample is strange.
you cannot compare with the outcome in solution - Measuring air? - do you place an identical glass as used for coating? - or is air 'nothing' on cell holder?
Putting a glass with or without coating into the optical path you will have transmission and reflection and scattering, the latter may be reduced by the coating. For sure compared to the glass alone the refractive index is changed leading to less reflection.
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