Current Group

Postdoctoral Researchers

Tarun Kumar Roy

Postdoctoral Researcher

Tarun was born in Kolkata, India. He obtained his master’s degree from Indian Institute of Technology Bombay with a specialization in physical chemistry in 2018. He received his Ph.D. in Chemistry from the Ruhr University Bochum, Germany, with Prof. Martina Havenith. Tarun joined the Lester group in summer of 2022. He holds DFG Walter Benjamin Fellowship for the postdoctoral research work in the Lester group at University of Pennsylvania. His current research is focused on the spectroscopy and unimolecular decay dynamics of reaction intermediates in atmosphere and combustion chemistry. Tarun enjoys cooking and watching sports in his spare time.

Graduate Students

Vincent Esposito
Ph.D. Student, NSF Graduate Research Fellow

Vincent was born in Lansdale, PA, about an hour north of the city of Philadelphia. He attended the University of South Carolina-Columbia where he pole vaulted on the Track and Field team and studied chemistry. He conducted undergraduate research in environmental analytical chemistry with Dr. Susan Richardson, where he studied the formation and removal of disinfection by-products in drinking water. Vincent joined the Lester group in the summer of 2018. In his spare time, Vincent likes to reminisce about the Eagles super bowl victory, cook, and study personal finance.

Guanghan Wang
Ph.D. Student

Guanghan was raised in Zhejiang, China, and he obtained his B.S. degree in Material Physics at University of Science and Technology of China. He joined Lester Group in 2017, and he’s currently working on the construction of the new VMI apparatus. Besides chemistry, he also enjoys cooking, mostly Chinese food, and playing some sports such as basketball or running. Hopefully, he will become a better cook than a scientist.

Tianlin Liu
Ph.D. Student

Tianlin Liu was born and raised in Shijiazhuang, China. She went to University of Science and Technology of China (USTC) to pursue her bachelor’s degree, and in 2018, she graduated with a B.S.. She then came to Penn, and at the beginning of 2019, she joined Lester’s group. Outside chemistry, she plays some traditional musical instruments from China.

Meijun Zou

Ph.D. Student

Meijun was born and raised in Jiangxi, China. During her undergraduate study in Nanjing University, she conducted some research on photophysical properties of perovskite under Professor Yuxi Tian. After graduating with a B.S. in chemistry, Meijun continued her study in the University of Pennsylvania. She joined the Lester Group at the beginning of 2020. In her spare time, Meijun enjoys a variety of hobbies including drawing, calligraphy and volleyball.



Yujie Qian

Ph.D. Student

Yujie was born in Jiangsu, China. She did her undergraduate in Chemistry at Pennsylvania State University. She studied the homogeneity of water-polypropylene glycol mixtures in her undergraduate research. She joined Lester’s group at the beginning of 2021. In her spare time, she loves watching movies.



Undergraduate Students