• Graduate students
Agrawal, Karan (MS)
Kolachure, Vidyalakshmi (MS)
Wang, Xin (MS, co-advised with Dr. Hao)
• Undergraduate students
Hutchens, Kyle (Electrical engineering)
Passes, Sean (Mechanical and aerospace engineering)
Thornburg, Erica (Chemistry)

Research Activities  
PML studies solar cell materials and devices. The goal of the lab is (i) to understand fundamental principles of photovoltaic process and find new concepts of photo-electric conversion, (ii) to study how material properties affects the photovoltaic process, and (iii) to develop new material synthetic processes to maximize the solar cell power conversion efficiency.
• Chalcopyrite Polycrystalline Thin-Film Solar Cells
Chalcopyrite thin film solar cell holds a world's best photo energy conversion efficiency ( ~ 20%) among single-junction thin film solar cells. Controlling the film composition is important because the material is doped with intrinsic defects created by off-stoichiometry. Thin film solar cell on polymer substrate is particularly interesting to realize flexible modules and the development of low-temperature process is currently in progress.
• Organic Solar Cells
Relatively large exciton dissociation energy (>0.1 eV) and short exciton diffusion length ( ~ 10nm) of semiconducting conjugated polymers require careful choice of materials and device structure. Bulk heterojunction photovoltaic device has achieved external quantum efficiency over 70% with photo energy conversion efficiency up to 5%. Further understanding of the conversion and loss mechanisms is necessary to improve device performance even further. Other important issues include poor red absorption and carrier transport of the conjugated polymer thin films deposited by solution-based methods and stability of the solar cells. Current activities include the realization of the ordered bulk heterojunction solar cells and the development of an inexpensive gas-phase process.

Facilities
• Material processing
- CVD tools for chalcopyrite compounds and conducting polymer deposition
- Selenization/sulfurization chambers
- Electrodeposition/electrochemical analysis
- Spin coater
- E-beam evaporator
- Chemical bath deposition
• Spectroscopy
- UV/VIS/NIR Spectrometer
- Fluorescence spectroscopy
• Solar cell characterization
- Solar simulator with an automated data acquisition system
- Quantum efficiency measurement set-up in progress