Advancing tandem solar cells by spectrally selective multilayer intermediate reflectors

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Thin-film silicon tandem solar cells utilize amorphous silicon top cells and microcrystalline silicon bottom cells in series.
• Effective photon management is crucial for matching photocurrents between the top and bottom cells.
• Current methods use single-layer intermediate reflectors with limited spectral selectivity.

Purpose of the Study:

• To design and prototype multilayer intermediate reflectors for enhanced performance in silicon tandem solar cells.
• To achieve spectrally selective reflectance for improved current matching.
• To increase overall charge carrier generation in tandem solar cells.

Main Methods:

• Design and fabrication of multilayer intermediate reflectors using aluminum-doped zinc oxide and doped microcrystalline silicon oxide.
• Integration of these reflectors into state-of-the-art tandem solar cells.
• Characterization of solar cell performance, focusing on short-circuit current density.

Main Results:

• The developed multilayer intermediate reflectors exhibit spectrally selective reflectance.
• Successful integration into tandem solar cells was achieved.
• An increase in overall short-circuit current density of 0.7 mA/cm(2) was observed compared to standard single-layer reflectors.

Conclusions:

• Multilayer intermediate reflectors offer a significant improvement over single-layer designs.
• Enhanced photon management via spectrally selective reflectors boosts tandem solar cell efficiency.
• This technology holds promise for advancing thin-film silicon solar cell performance.