Thermoelectrics and their Applications

After doing research for a couple of months, I look back at the time I first started, and its quite fascinating how much ground I have covered since then.  From the time I started, I have come quite far in terms of understanding of the subject matter.  I have gained a better understanding of what the field of thermoelectrics is all about.  Working in the lab has been awesome.  It makes me feel like everything I have learned through school, I am actually implementing in the lab.  It provides the hands on experience that every student should experience.  It is one thing when you learn things throughout school and from reading books and it is something totally different when you actually perform in the lab and apply what you learn.

I have learned about the many applications of thermoelectric materials and they are quite interesting.  However, one that really intrigues me is the application of thermoelectrics in cars.  Many car manufacturers are looking to implement thermoelectrics in their cars so that they may be able to use waste heat from the car and convert it into usable energy.  The way they would be able to do this is by using thermoelectric materials near the tail pipe of the car, where hot air produced from the engine leaves through the back of the car.  These thermoelectric materials would be able to use the temperature gradient produced and turn it into electricity that the car can use for various instruments inside it.  This is one of the many applications of thermoelectrics and how they are used in various ways.

Thermoelectrics, research, and all school related stuff put aside, it has been a quarter full of fun and learning.  I’m looking really forward to break, relaxing, and a lot of catching up on sleeping, and lastly next quarter of school and research.  I’m excited for the future, what’s to come, and being able to do research in my lab along with my group.

Also, I’d like to thank Ryan Need and Rachel Koltun for their guidance, patience, and for being great mentors helping me throughout my research experience.

Getting My Mind Off School to Get Motivated for School

There are some days where I feel absolutely burned out. Whatever the reason, I just don’t feel like I’m making much progress with studying or research. Sometimes it’s best to take a short lived break during the quarter (maybe an evening or so)! To get my mind off of school, I stop whatever I am doing (of course, only if it does not conflict with any nearing deadlines!) and go for a run! Or a bike ride! There are countless articles in both peer-reviewed journals and newsletter magazines that talk about the factual and anecdotal benefits of exercise. In a “Letters to the Editor” section of the Primary Care Companion Journal of Clinical Psychiatry, Dr. Ashish Sharma, Dr. Vishal Madaan, and Dr. Petty write about the benefits of exercise and mental health, in their article “Exercise for Mental Health.” They state, “Aerobic exercises, including jogging, swimming, cycling, walking, gardening, and dancing, have been proved to reduce anxiety and depression. These improvements in mood are proposed to be caused by exercise-induced increase in blood circulation to the brain and by an influence on the hypothalamic-pituitary-adrenal (HPA) axis and, thus, on the physiologic reactivity to stress.” The authors go into further details on the scientific reasoning behind the linkage of exercise and better mental  health, but the message is clear, exercise helps!  (Link to the letter)

A participant in the STEM field is more or less likely to spend many hours sitting down. The demands of studying and pursuing research can add on a lot of stress, so I’ve found exercise to be quite a good outing. The beaches near UCSB are really a great place for a run on a sunny afternoon. Even more, the bike paths in Santa Barbara are great to ride through if you haven’t experienced it yet! The bike path that leaves past the engineering buildings go well past the Henley Gate and these lead to long, relatively flat bike paths (favorable for any one who rides fixed-gear!) that reach the downtown Santa Barbara area, which are not as flat as the path near UCSB. Sometimes, a small break from school, research, and academic work is needed to get back into the game. It’s like restarting your computer after it’s been left on for days!


Getting Integrated into the System

For the first couple months, I learned quite a bit about thermoelectrics and some experimental procedures. It was such a flood of information though, that a lot of it did not settle in. The last couple months (I am now in my fourth month of research with CEEM) I have really started understanding more of the details of what I have been researching. In addition to getting some of the experimental methods down, I have started understanding the bigger picture.

Recently I’ve been involved with researching the figure of merit of thermoelectric materials, which is basically just a measure of their efficiency. We have obtained data on important physical parameters, such as the carrier concentration, the mobility, the Hall coefficient, and the electrical conductivity. The figure of merit depends on all of these parameters in some shape or form, so I have been learning about the trends that certain semiconductor materials exhibit while varying temperature. We are interested in the efficiency at numerous different temperatures, although currently thermoelectrics are being looked into for higher temperatures. This is why we run our materials in both a low temperature setup (ranging from approximately 10-300K) and a high temperature setup (ranging from 300-750K). I have done quite a bit of data analysis on both low and high temperature measurements, and from this raw data I am getting a better idea of the physics behind semiconductors and thermoelectric research.

Ever since beginning research with CEEM, my opinion of research has changed drastically. I used to think it was somewhat important to my future, including building my resume and getting experience. Now I believe it is the best thing you can possibly do during your undergraduate education. Learning concepts in class and applying them to real world technology is such a massive bridge to cross, and personally, I believe that the vast majority of concepts and experience can be formulated from on the job training. While I still think forming a strong base in the classroom is important, my understanding for condensed matter physics and materials has risen exponentially since beginning this internship. If I had tried to take a theoretical approach to understanding the research being done with thermoelectrics before starting this internship, I would have had no idea where to begin. Seeing it actually done increasing my learning curve drastically, and now I can safely explain the general concepts behind the research being done here at UCSB on thermoelectrics.

Atomic Force Microscope: A Tiny Record Player

As an undergraduate researcher I have become very familiar with using an atomic force microscope.  This amazing tool uses a very small device called a cantilever, which is basically a tiny record player needle made of silicon.  The machine taps the tip of this cantilever along the surface of the thing you’re trying to image and generates an image based on the interactions of the cantilever tip with the sample.  The movements of this cantilever are measured by bouncing a laser off the back of it and measuring how the deflection of the laser changes using a photodetector.  When the laser goes over a bump the laser will also move and a photodetector which collects this light records this change.

 Now most of the time the thing you’re trying to look at is already so smooth you cannot tell that there is any flaw by looking at it with your eyes, or sometimes even an optical microscope.  The atomic force microscope however is amazingly detailed and is able to draw an extremely detailed picture of what the surface if your sample looks like.

This image shows a 4 sided pyramid structure which grew as a result of a threading dislocation in a crystal I was growing.  The lines you see on this pyramid are actually atomic steps. Yes you read that correctly, they are layers which are a single atom thick. How’s that for high resolution?

I am consistently amazed with the information this tool is able to gather.  This amazing technology allows for tremendous insight into materials science.  In this field where there are countless different polymers, and crystals which are being grown and synthesized by scientists; having the ability to look this close at the structure of the material itself can lead to a much deeper understanding of how these materials actually form and function.

Perception: an invaluable tool

This quarter has been absolutely brutal. This quarter has been challenging yet fruitful. Can’t it be spring break already? How are we already in week 10!?

Perception can be both a powerful tool and one’s own worst enemy. Throughout this quarter I’ve noticed that my state of mind has often volleyed between both of these arenas. This quarter has been very challenging. At times I’ve felt completely overwhelmed and at odds with the world. Contrastingly though, there have also been many instances in which I’ve felt absolutely ecstatic, eager to face the challenges of the day and days ahead.

Lately, I’ve really begun to become cognizant of the power of perception. I’ve started to understand how simple changes in my perception of workload or challenges can drastically alter my motivation levels and as a result, my ability to get work done. Often times it can be very easy to feel helplessly overloaded by school, work, social commitments and life in general, but, I’ve found that simply embracing a positive outlook with regards to one’s circumstances can truly aid in increasing productivity and goal achievement.

In the chance that some of you are curious about my means of perception improvement I’ll present some of my personal favorite perception improving recipes which help me get a grip on a challenging situation, stress, or simply life in general. To start, I find exercise to be an invaluable tool for staving off stress. If I’m feeling extremely tense or unsettled exercise really helps me return to a more relaxed, yet motivated state of mind.  I also frequently refer to a somewhat unorthodox, but highly motivating “mind game.” In the case that I’m feeling overwhelmed, I try to find a role model, be it celebrity, athlete, scientist, really anybody—and I try to “compete” with them. To elaborate, I try to find someone known for working very hard and I then try to outwork them in terms of time dedication, albeit usually in a completely different context. I admit that this method may seem rather unorthodox, but nevertheless, it really helps me to stay motivated and also forces me to acknowledge that there are many others out there who have faced and surmounted much greater barriers than the ones I’m currently trying to pass. Last but not least I’ll share my favorite method for attaining a quick boost in mood: a breath of fresh air. Simply stepping outside of the lab, library, home, or other confined environment for a few moments and taking in the sights, sounds, and smells of the outside world really helps boost my mood in almost any circumstance.

I am also curious to see what tools you use to improve your outlook, mood, or perception. If you have anything that helps you get back in the zone please do share below.