My name is Rebecca Cooke. I have been teaching for the past nine years and I am currently teaching Biology, Anatomy & Physiology, Zoology, and Biomedical Science at Douglas High School.
This is my second year participating in RET. Last year, I participated in RET where I worked to genetically engineer a bacterial plasmid with fluorescent proteins to serve as a live-dead reporter system. I had such a great time last year and was thrilled to be invited back.
About the Lab: This summer I am working in the Rao lab in the LEAP (Lab for Education and Application Prototypes). This particular lab is focused on photonics, which is to process information using light instead of electricity. These devices are often faster and can use less power, and can be made at a much smaller scale. The lab in which I am working within this department is discovering, understanding, and developing advanced materials for many applications, including solar energy conversion catalysis, printed electronics, sensors, and functional coatings. This lab includes work in materials science, mechanical engineering, solid state physics, and thermal sciences.
Project: Improving Coating Methods for Thin Photocatalyst Films for Potential Hydrogen Fuel Production from Water
- Week 1: This week we were in the lab and we learned how to synthesize a batch of CBTO from start to finish. I also learned some of the equipment and techniques I will need in order to coat the conductive glass. For instance, I learned how to make the CBTO slurry, I learned how to cut and the basic procedure for cleaning the glass. Next, I spin coated and annealed the CBTO. I also met with my graduate mentor to narrow down which spin coating parameters I will try. We also went to a different lab in order to do X-ray diffraction on CBTO samples in order to determine their purity.
- Week 2: This week I began producing films by spin coating. I produced a number of different samples by adjusting the speed at which the spin-coating happened. We found that the films looked very uneven at slower speeds, so I made a few samples where they were spun at higher speeds and I also ran a sample that began slowly to spread CBTO on the glass, then increased the speed. I also annealed the films so that they will be ready for analysis using the digital microscope and stylus profilometer. I also presented last year’s poster at the 2023 NSF Virtual poster session.
- Week 3: This week I received training on two devices needed to analyze the films, the Keyence digital microscope and stylus profilometer. I have created the plan for how I am going to collect my data using the microscope. The microscope has a grain count feature that will measure the percentage of the field of view that is covered with the particles. I complete the grain count across my films at different magnifications in order see how much of the area is covered. The stylus profilometer is a device that measures the height of the CBTO particles across the surface of the film. Ideally we would like a thin and smooth film across the surface.
- Week 4: This week, I used the microscope and stylus profilometer in order to analyze my films. So far, I have found that increasing the speed of the spin coater leads to less area covered by the CBTO on the FTO glass. Ideally, we would want the entire surface covered so I made a concentrated batch of the CBTO slurry and annealed them. I also learned how to interpret the data from the profilometer. When I compared the 2000 and 4000 RPM films, I was able to confirm that the films were more even, however, there were wider gaps between the peaks showing that there were larger spaces in between the CBTO particles.
- Week 5: This week, I looked at how concentrating the CBTO slurry affects the coverage of the films. I concentrated the CBTO slurry to 20%, 30%, and 40%. I found that the 30% concentration more completely covered the FTO glass more consistently than the 20 or 40%. 40% was better than the 20% concentration, but at this high concentration the slurry is more paste-like and is more difficult to dispense onto the FTO. A lot of CBTO was stuck in the pipette tip, so the decrease in coverage could be because less CBTO was dispensed onto the film. I was also taught how to turn the films into electrodes and was shown how to do PEC testing. We took one film that was covered with the CBTO evenly and another that had scratches on it. We saw that dark current was driving the reaction with the scratched film, but the film that did not have any scratches, although had a thinner layer of CBTO on it, was better.
Poster and Lesson Plan: