Bulovic Group: Yasu Shirasaki

Meet EECS PhD candidate Yasu Shirasaki, member of the Bulovic group. Yasu works in the Organic and Nanostructured Electronics, the ONE lab most of the time, testing new LEDs (light emitting diodes), though he enjoys checking in with other group members to enjoy the breadth of applied research within the Bulovic group.

Yasu, how did you find the Bulovic lab (or did it find you?) and what attracted you to it?

Yasu Shirasaki:
“Back when I was an undergraduate at MIT, my interests were EE and physics so I looked for a research group that required understanding of both. In particular, I was interested in fabricating practical devices while understanding the working mechanisms behind them. There are many groups that do research with great science but not many are as practical as the research done in the Bulovic group. The research in this group include MEMS, solar cells, photodetectors and LEDs, and it is this variety as well as the practicality of these research that initially attracted me to this group. After I learned about the group on its website, I walked into Vladimir’s office one day to ask him about his research. I was fascinated by his enthusiasm and his wealth of knowledge and I quickly became really excited about the group.

How has your role within the lab evolved from those earlier days?

Yasu Shirasaki:
“My earlier days consisted of following around experienced graduate students in the group and trying to absorb their wisdom as much as possible. It was very helpful to learn fundamental physics as well as practical device fabrication techniques from them. Now, I hope what I’ve learned is useful to others in the group.”

What are the strongest assets you find in the lab group that have allowed you to grow, as a person? as a scientist/engineer?

Yasu Shirasaki:
“One of the strongest assets in the group is, again, the variety of research in the lab. Because of this variety, we have opportunities to learn about different research fields from each other’s work. I work on LEDs but I really enjoy learning about different fields like solar cells from my labmates’ work.

Additionally, our group has a very supportive atmosphere. It is often from a group mate that we learn new things and get help when an experiment doesn’t quite work. I think we benefit from both teaching/helping each other and getting taught/helped.”

Could you give an ‘elevator pitch’ for the latest research you are doing that might have practical significance or be of interest to a future student?

Yasu Shirasaki:

“The research that I work on centers around inorganic semiconductor nanocrystals called colloidal quantum dots. These are luminescent particles suspended in solution that can potentially be used to fabricate inexpensive, large area light-emitting devices. These nanoparticles have the amazing property of being able to change its emission color by simply tuning the size of the particles. This means we can fabricate LEDs that emit any color in the visible spectrum by simply choosing the size of the particles we incorporate into the device without changing other parts of the device.

Unlike traditional inorganic LEDs that require expensive crystal growth, these LEDs can be fabricated using layers of amorphous films which can significantly lower their costs. And because of the quantum dots, these LEDs also have more saturated color than relatively inexpensive organic LEDs and have the potential of being more stable. We study the working mechanism of these devices and explore different ways to electrically excite these materials. With the 20 % of the US energy consumption going into lighting, advancing solid state lighting technology is both interesting and important.”

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