High efficiency graphene solar cells by chemical doping

Area of Science:

• Materials Science
• Renewable Energy
• Semiconductor Physics

Background:

• Graphene-based solar cells offer potential for low-cost, flexible photovoltaic devices.
• Schottky junction solar cells utilize a metal-semiconductor interface for charge separation.
• Achieving high power conversion efficiency (PCE) in graphene solar cells remains a challenge.

Purpose of the Study:

• To investigate the impact of graphene doping on the performance of single layer graphene/n-Si Schottky junction solar cells.
• To achieve a record power conversion efficiency for graphene-based solar cells.
• To elucidate the mechanisms behind performance enhancement through doping.

Main Methods:

• Fabrication of single layer graphene/n-Si Schottky junction solar cells.
• Doping of graphene using bis(trifluoromethanesulfonyl)amide.
• Characterization using current-voltage (I-V) and capacitance-voltage (C-V) measurements under AM1.5 illumination.
• External quantum efficiency (EQE) measurements.

Main Results:

• Demonstrated a power conversion efficiency (PCE) of 8.6% for doped graphene/n-Si Schottky junction solar cells.
• Achieved a 4.5-fold performance improvement compared to undoped devices.
• Established a new record PCE for graphene-based solar cells.
• Observed increased graphene carrier density and built-in potential due to doping.

Conclusions:

• Graphene doping with bis(trifluoromethanesulfonyl)amide significantly enhances Schottky junction solar cell performance.
• Doping improves PCE by increasing carrier density (reducing series resistance) and built-in potential (increasing open-circuit voltage).
• This work represents a significant advancement in graphene solar cell technology.