Design of Grating Al₂O₃ Passivation Structure Optimized for High-Efficiency Cu(In,Ga)Se₂ Solar Cells

Area of Science:

• Photovoltaics
• Materials Science
• Semiconductor Devices

Background:

• Thin-film solar cells, particularly copper indium gallium selenide (CIGS), are crucial for renewable energy.
• Achieving high power conversion efficiency in CIGS cells requires minimizing carrier recombination and maximizing light absorption.
• Surface passivation is a key strategy to enhance the performance of thin-film solar cells.

Purpose of the Study:

• To propose and optimize a novel structure for thin CIGS solar cells using a grating aluminum oxide passivation layer (GAPL).
• To investigate the impact of structural parameters, specifically contact opening width (COW) and GAPL pitch, on cell efficiency.
• To enhance the power conversion efficiency of thin CIGS solar cells through advanced optoelectrical simulations.

Main Methods:

• Optoelectrical simulations were employed to design and analyze the optimized solar cell structure.
• A grating aluminum oxide (Al2O3) passivation layer (GAPL) was integrated to provide nano-sized contact openings.
• Key structural parameters, including contact opening width (COW) and GAPL pitch, were systematically varied.

Main Results:

• The optimized structure with GAPL significantly improved efficiency compared to unpassivated cells.
• An efficiency of up to 20.38% was achieved with a GAPL pitch of 7.5-12.5 μm.
• Maximum efficiency was obtained at a COW of 100 nm, attributed to effective carrier recombination inhibition and high Al2O3 reflectivity.

Conclusions:

• The proposed optimized structure with a grating aluminum oxide passivation layer offers a viable pathway to high-efficiency thin CIGS solar cells.
• Careful manipulation of COW and GAPL pitch is critical for maximizing photovoltaic performance.
• This design provides valuable insights for photovoltaic generator and sensor designers seeking to enhance photosensitive CIGS devices.