Georgia Tech School of Electrical and Computer Engineering Ph.D. student Ruohan Zhong won the Best Student Paper Award at the 54^th IEEE Photovoltaic Specialists Conference.

She was recognized for her paper titled, “Characterization and Modeling of 24.3% Copper Contacted n-TOPCon Solar Cell with Screen Printable Copper Pastes.”

The research focused on replacing silver with copper in solar cell manufacturing.

Many of today's high-efficiency solar cells rely heavily on silver electrodes, but silver is one of the most expensive materials. Copper offers an inexpensive alternative, according to Zhong. However, copper is much harder to integrate into high-efficiency solar cells while maintaining the same performance and without overcomplicating the fabrication process.

The challenge arises from copper’s fast diffusion into silicon, which can dramatically degrade the solar cell performance.

“The specially designed copper paste used in this research overcomes that challenge by forming a copper-rich oxide layer that blocks copper diffusion while maintaining good ohmic contact,” Zhong said.

Zhong’s research proposes a novel copper paste that can produce copper-contacted solar cells, which have shown results nearly as good as silver-contacted solar cells.

“This will help make solar panels more affordable and accelerate the transition to clean energy,” Zhong said. “This innovation also greatly simplifies the manufacturing process and brings copper electrodes closer to large-scale industrial solar cell production.”

The research was done in the University Center of Excellence for Photovoltaics, under the guidance of her advisor, Professor Ajeet Rohatgi.

The next goal for the research is to combine copper contacts and aluminum contacts to make a silver-free solar cell.