Graphene oxide-based carbon interconnecting layer for polymer tandem solar cells

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Tandem polymer solar cells (PSCs) offer higher power conversion efficiency than single-junction cells.
• The performance of tandem PSCs is critically dependent on the charge recombination layer, also known as the interconnecting layer.
• Achieving a high open-circuit voltage (Voc) close to the sum of individual subcells is crucial for ideal tandem device performance.

Purpose of the Study:

• To develop and evaluate an efficient interconnecting layer for tandem PSCs.
• To investigate the impact of graphene oxide (GO) and its cesium-neutralized form (GO-Cs) modified with Al and MoO3 as an interconnecting layer.
• To maximize the open-circuit voltage (Voc) in tandem PSCs.

Main Methods:

• Fabrication of a tandem PSC device utilizing a bilayer of graphene oxide (GO)/GO-Cs.
• Modification of the GO/GO-Cs bilayer with ultrathin layers of aluminum (Al) and molybdenum trioxide (MoO3).
• Characterization of the device performance under standard AM 1.5 solar simulation conditions.

Main Results:

• The developed GO/GO-Cs bilayer, modified with Al and MoO3, functions as an effective interconnecting layer.
• The tandem PSCs achieved a significantly increased open-circuit voltage (Voc).
• The Voc reached nearly 100% of the sum of the individual subcell V(oc)s, indicating efficient charge recombination and voltage summation.

Conclusions:

• The modified GO/GO-Cs bilayer serves as a high-performance interconnecting layer for tandem PSCs.
• This approach enables efficient voltage summation across subcells, leading to improved overall device efficiency.
• The study demonstrates a promising strategy for advancing tandem solar cell technology through advanced interconnecting layer design.