Preliminary Measurements

My first two weeks of research have been very busy. Since I am investigating a new family of dyes, which the lab has not worked with before, I have a lot of preliminary data to collect before I can begin. This has mostly involved figuring out the laser parameters that maximize the fluorescent intensities of the molecules. The power settings of the 532 nm laser are crucial, since too much power will cause the molecules to degrade, or photobleach, but too little power will result in intensities that are too low to be measured. My final fluorescent measurements will be taken at a very low concentration of the dye, but because of the sensitivity of the laser and all of the unknown settings, I began looking at higher concentrations. From there, I have been trying to optimize the power settings at each concentration before decreasing it. I am very close to the settings that I need, and should be able to measure the time-dependent fluorescence, or blinking, by the end of the week.


Another question I need to answer before I really begin is which form of my dye molecule I have present in my dilute solution. Both eosin y (EY) and fluorescein (FL) are pH dependent, meaning there are several different forms of each dye, which would exhibit different electron transfer (ET) kinetics when excited by the laser. In order to understand the ET dynamics, I need to first understand the structure. Dye structure also impacts its ability to function in a photocatalytic solar cell, so this data is vital to my thesis. My next step will be to do titrations on the dye solution and to take absorbance and emission spectra for each dye at varying pH to determine which structure I am working with. After that, I will begin my blinking studies of EY and FL.


  1. cgfarling says:

    Sounds like a great start to your thesis, Polly! I wish you luck as you conduct titrations to determine the structures of the dyes that you are working with. Looking forward to reading more about how these dyes behave when excited by the laser depending on what form they are in and the other variables in your research.

  2. srfranklingill says:

    That seems like a lot of preliminary work, but clearly very important as you don’t want to ruin your molecules with the wrong power setting. It’s cool that you are working with dyes that your lab has never used before, but that also must make it harder to work without as much guidance. I’m glad you are making progress and enjoying your work so far!

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