Solar photons beyond the band gap wavelengths: their effect on solution-processed solar cells

Area of Science:

• Materials Science
• Renewable Energy
• Optoelectronics

Background:

• Solution-processed solar cells (SSCs) require detailed performance analysis under varying conditions.
• Current characterization often overlooks wavelengths above the band gap, limiting understanding of operational losses.

Purpose of the Study:

• To provide comprehensive full-spectrum optical characterization and analysis of organic solar cells (OSCs) and perovskite solar cells (PSCs).
• To investigate the impact of parasitic absorption and conversion losses on operating temperature and power conversion efficiency (PCE).
• To identify optimal conditions, materials, and architectures for reducing device temperature and PCE losses.

Main Methods:

• Experimental optical characterizations across the full solar spectrum (approx. 300-2500 nm).
• Theoretical optical-thermal-electrical analysis for various single-junction and tandem SSCs.
• Analysis of solar photons both below and above the band gap (λg).

Main Results:

• Parasitic absorption above the band gap significantly affects operating temperature and PCE.
• Identified key factors contributing to temperature-induced PCE losses in OSCs and PSCs.
• Demonstrated potential to reduce PCE losses by up to 7 times compared to silicon solar cells.

Conclusions:

• Full-spectrum analysis is critical for optimizing SSC design and performance.
• Understanding parasitic absorption and thermal effects enables significant improvements in PCE.
• Optimized SSC architectures show promise for superior real-world performance over silicon-based technologies.