Dye doped spectroscopy interpretation

In summary, the person is working on a dye doping project and is seeking help in interpreting the physical meaning of a graph from a photospectrometry result. They mention that the graph shows negative absorbance and may be due to incorrect calibration or outside sources. They also mention that their sample is diluted and ask if they should zero the spectrophotometer over the entire wavelength range and what solvent they should use. They clarify that their sample is a solid thin film on a glass slide and mention concerns about fluorescence. Other participants suggest using quartz cuvettes and increasing the concentration for better results. There is also discussion about the effects of the solvents and other substances in the sample on the UV-Vis spectrum.
  • #1
Srv44
3
0
Hello all,

I am working on a dye doping project and got a photospectrometry result as show in a picture for my thin film. Can anyone please help me interpret the physical meaning of the graph below? Thanks!

upload_2016-7-20_11-58-1.png
 
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  • #2
Negative Absorbance, the same as measuring light that is either generated by something other than the Spectrometer (reflections from an outside source?); or equivalently the calibration is incorrect.
 
  • #3
Your sample is very dilute with an absorbance of 0.03 AUFS. Most dyes have incredibly high molar absorption values in the visible range. Did you zero your spectrophotometer over the entire wavelength range? What is your solvent?
 
  • #4
Kevin McHugh said:
Your sample is very dilute with an absorbance of 0.03 AUFS. Most dyes have incredibly high molar absorption values in the visible range. Did you zero your spectrophotometer over the entire wavelength range? What is your solvent?

Kevin, yes I did zero the spectrophotometer, and the sol I used is made up of : Tetraethyl orthosilicate, Ethanol, hydrogen phosphate and water.
 
  • #5
You mention a thin film, is your sample a solid or a liquid? Are you using quartz cuvettes, or a holder for solid thin film?
 
  • #6
Kevin McHugh said:
You mention a thin film, is your sample a solid or a liquid? Are you using quartz cuvettes, or a holder for solid thin film?

My sample is a solid, so a film of dye coated on a microscope slide. Thats all it is. While getting the spec data, I place the dye coated slide right on the beam path against the cuvette holder. Is that something that affects the data I get?
 
  • #7
Either the glass slide or your sample may fluoresce. I've had cheap photograph lens filters fluoresce Red when hit with intense Blue light. Most annoying.
 
  • #8
You probably need to use quartz. Are you using a dual beam instrument? Also, your path length will be variable, no good for quant work. How are you zeroing the spec? Your baseline looks like the machine isn't comparing similar backgrounds. Using quarts cuvettes, with dye in solution at known concentration is your best bet to successful spectroscopy. Increase your concentration to achieve at least 1 AUFS for best results. Use methanol as your solvent, it is clear to 205 nm.

Edit: Belay the last, I see your casting a thin film. I believe there sample holders that use mm scale spacers for thin film work in solution. You would do well to get them. Use quartz.
 
Last edited:
  • #9
  • How do the orthosilicates and the phosphate affect the UV-Vis spectrum? I would expect them to be optically clear, but there may be some other phenomenon going on between the adjutants and the dye.And, as Tom said, does your sample fluoresce? What does the spectrum of the pure dye in ethanol/water look like compared to in solution with the orthosilicates and phopshate>
 

Related to Dye doped spectroscopy interpretation

What is dye doped spectroscopy interpretation?

Dye doped spectroscopy interpretation is a technique used to study the properties and behavior of dyes and other optically active materials. It involves using a spectroscopic method, such as absorbance or fluorescence spectroscopy, to analyze the light absorption or emission of a dye doped sample.

How does dye doped spectroscopy interpretation work?

In dye doped spectroscopy interpretation, a sample is prepared by incorporating a dye into a host material. The sample is then exposed to a specific wavelength of light and the resulting absorbance or fluorescence is measured. This data is then used to determine the properties of the dye and the interactions between the dye and the host material.

What are the advantages of using dye doped spectroscopy interpretation?

Dye doped spectroscopy interpretation allows for the study of dyes and other optically active materials in their natural environment, rather than isolated in a solution. It also provides information about the electronic states and energy levels of the dye, which can aid in understanding its behavior in various applications.

What are some common applications of dye doped spectroscopy interpretation?

Dye doped spectroscopy interpretation has many applications in fields such as materials science, biotechnology, and environmental science. It is commonly used to study the properties of dyes in various mediums, as well as the interactions between dyes and other materials.

What are some potential challenges in dye doped spectroscopy interpretation?

One challenge in dye doped spectroscopy interpretation is ensuring that the dye is evenly distributed in the host material, as this can affect the accuracy of the results. Another challenge is choosing the appropriate spectroscopic method and conditions to obtain reliable data. Additionally, interpretation of the data can be complex and require advanced analytical techniques.

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