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The votes are in. Brianfredo Dalefino Gilbertega is the winner. Frankly, I’m just glad some people actually voted.
Surprisingly, scanning electron microscopy (SEM) isn’t as exciting as it might sound. I know, I was shocked too. A lot goes into SEM. First, you have to coat your samples. I’ve been coating mine with gold and palladium (not enough to get rich on though). Then, you have to sit around while the vacuum chamber that your samples will be placed in vents (generally three whole minutes!), put the samples in, and pump it back down (another three minutes!). After that you have to turn on the electron gun (cool) and align everything. Just getting ready takes about twenty frickin minutes!
After all of that, you take pictures of your samples. Here’s one I got yesterday of a silica nanosphere (ok, nanoball) array: Read the rest of this entry »
I’ve decided that I really like being back in a research group. Especially as a visiting professor – no classes to teach, no committee work, no advising. Just regular lab work. In other words, fun! So what, exactly am I doing here, and what is the group like? I’m sure that’s exactly what you’re all wondering. If you aren’t, too bad, because that’s what this sabbatical post will be about. If you want to know about something else, leave it in the comments and I’ll write about that sometime.
So I’ve been here for about 1.5 weeks with most of that time taken up with moving into our sabbatical house, getting our daughter into her school, and starting paperwork on campus so that I can have an ID, buy stuff in the stockroom, etc. Finally, in the last couple of days, I’ve been able to get into lab, which, of course, was the whole purpose for my coming here in the first place. Well, that, and to get away from teaching, committees and normal life for a while.
As I’ve mentioned before, working at the University of Arizona is a bit of a homecoming for my wife and I; we both recieved our bachelor’s degrees here about 20 years ago. I’m working with Jeanne Pemberton, who was one of my professors almost 21 years ago! The goal of the project I’m working on is ultimately to make novel nanoparticle based “hole acceptors” for solar cells, which would replace the ubiquitous indium tin oxide (ITO) based interfaces.
We are trying to make the collectors (this may be the wrong terminology – I’ve still got jargon to learn) by first forming 3-dimensional arrays of monodisperse silica nanospheres (SNS). When these are made, I’ll try to add 10 nm or so sized gold nanoparticles (Au-NP). After that, the SNS will be removed chemically, and we’ll be left with a 3-D array of Au-NP.
I’m starting out by trying to make the SNS, using recipes that one of Jeanne’s recent Ph.D. students had in his dissertation. I need to make sub 100 nm spheres, with a small relative standard deviation (< 13%), which I’ll measure by dynamic light scattering. I’ve started making some particles already – here’s a picture. Later today, I’m going to learn how to use the department’s new scanning electron microscope (SEM), and still later, the transmission electron microscope (TEM). So, lots of surface science!
So, Cp (Copernicium) is named after an astronomer. Seems strange to me.
After thirteen (!) years of professing, I’m finally on sabbatical! Hard to believe that it’s finally happening and that it took so freakin’ long! I’m not sure what to expect from this, but I’ll try to blog thoughts about sabbaticals as I go. Right now, most of my thoughts are about how incredibly difficult it has been to set up.
Rather than wallow in self-pity though, I thought I’d post a list of things I wish I knew before I started thinking about a sabbatical:
Read the rest of this entry »
Dylan is getting closer (we hope) to figuring out some of the conditions necessary for SERS of lysozyme and bovine serum albumin (BSA). On Monday we figured out that a lot of what we were seeing in our spectra were bands from the phosphate buffer [1]. That’s what happens when you do control experiments! Since then, we decided to stop using the buffer and use DI water as our solvent.
Now Dylan has several (ok, lots) of spectra with broad bands that match up with the solid state lysozyme Raman spectrum we have (which matches up exactly with all the published spectra except one!). We aren’t sure why the bands are as broad as they are. One hypothesis is that our colloids have broad size distribution and we are observing a bulk average of many different SERS active sites. We plan to make more colloids and aim for a narrower extinction spectrum, which would indicate a more monodisperse colloid. Failing that, we may try core-shell nanoparticles, starting with an Au seed.
Dylan has also tried making Ag colloids using borohydride as the reducing agent [2]. The initial results looked good, but after storing them they aggregated. With colloids, cleanliness is very important.
[1] I think this is also in some published spectra too, not necessarily assigned correctly. More on that later.
[2] This is one of the several “Lee and Meisel” preps. Moral – if a paper says “Lee and Meisel method”, it could be one of up to four different preps for silver colloids. Reviewers need to tell authors to be more specific.
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