Thursday, May 14, 2015
Platinum and Titanium and Gold
The final written report for 20.109 was a summary of sorts, covering the construction and testing of our dye sensitized solar cells. Before I started this module, the idea that I could coax viruses into growing precious metals seemed ridiculous. How was I supposed to convince a tiny little phage to make gold and titanium nanotubes that would become part of a solar cell?
What? They can do that? I had no idea that they could do that!
The answer? Through a lot of cooling and mixing of the phage in nanoparticles of gold and titanium oxide. The nanotubes were eventually integrated into a dyed paste that became the heart of our solar cell. All of the 20.109 teams were able to test their solar cells in a solar simulator in the Belcher lab. We didn’t do too bad at all - our little solar cell had 2.8% efficiency (to put that number into perspective, one of the highest solar cell efficiencies in the history of 20.109 was around 4%)! We got a chance to see the titanium and gold structures under a TEM later on. While gold was hard to find, our solar cell had a ton of crystallized titanium, and even displayed some phage-length titanium wires!
We did it!!!!!!
But back to the Mod 3 summary. While we had been having fun assembling our solar cells and seeing them in action, we still couldn’t slide away into the summer without analyzing our data. We got all of the solar cell data and TEM images and started typing away. This was when I really was happy to have the Platinum team of three. Sure, we were that team in the back of the lab, the overflow team, the team that had to constantly re-divide tasks between three people no matter how awkward it was (cough, tissue culture hoods, cough), and the team that an extra set of samples to analyze in one module. We also didn’t know one another that well at the beginning of the semester. Like Will said, the first couple of weeks was a lot of tripping over one another and forgetting to grab extra buffers and water because we had another set of samples to run through. But as the weeks went on, we figured out a way to assembly line a lot of the procedures, and soon we weren’t always the last group to exit the lab. We subbed for one another when club trips happened and we always had things to chat about during the awkward 10min incubation times that came up. So when we had to write a report summary in 4 hours that last day in lab, we quickly got working away, automatically splitting the summary into sections due to our strengths, but also leaving time for all of us to discuss the results together and come up with a consensus on how to interpret it.
We saw that the size of the gold nanoparticles didn’t have much of an effect on the efficiencies of the solar cells and that the differences in dye absorption between the T/Th and W/F classes made a large disparity in the final solar cell efficiencies. We puzzled over the lack of gold in our TEM images and contemplated future changes that we could make to the solar cells to make them more efficient (Thinner doctor blading? Longer gold incubation times?). We finished and left early(!) and walked back home, ready to meet up later that weekend to work on our research proposal. We still had that last presentation to do but for a last day in lab? Not bad. And we came so far since the first day.