High Efficient Solar Cell Based on Heterostructure Constructed by Graphene and GaAs Quantum Wells

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• Graphene exhibits promising optoelectronic properties but faces limitations in solar cell power conversion efficiency (PCE).
• Graphene/GaAs heterostructures are explored for advanced photovoltaic applications.

Purpose of the Study:

• To enhance the PCE of graphene-based solar cells.
• To investigate the role of carrier multiplication (CM) in graphene/GaAs heterostructures for improved solar energy conversion.

Main Methods:

• Fabrication of a graphene/quantum wells/GaAs heterostructure solar cell.
• Experimental measurement of power conversion efficiency (PCE) and open-circuit voltage (Voc) at 90 K.
• Analysis of external quantum efficiency (EQE) across different wavelengths.

Main Results:

• Achieved a PCE of 20.2% and an open-circuit voltage (Voc) of 1.16 V at 90 K.
• Demonstrated a significant increase in external quantum efficiency (EQE) up to 72.2% in the ultraviolet range.
• Observed enhanced EQE with decreasing light wavelength, attributed to the carrier multiplication (CM) effect.

Conclusions:

• The graphene/quantum wells/GaAs heterostructure solar cell demonstrates a viable pathway to high PCE.
• The carrier multiplication (CM) effect in graphene is crucial for boosting solar cell performance.
• This approach offers a potential method to surpass the conventional Shockley-Queisser (S-Q) limit for solar energy conversion.