Performance enhancement of fullerene-based solar cells by light processing

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Organic bulk heterojunction solar cells face commercialization hurdles due to poor morphological stability under thermal stress.
• Achieving long-term operational stability is crucial for widespread adoption of organic photovoltaic technologies.

Purpose of the Study:

• To investigate the impact of a low-level light exposure processing step on the thermal stability and performance of polymer:PC60BM solar cells.
• To elucidate the mechanism behind light-induced stability enhancements in organic solar cells.

Main Methods:

• Fabrication of polymer:PC60BM solar cells with an integrated low-level light exposure step.
• Thermal stress testing of fabricated solar cells to evaluate morphological and device stability.
• Analysis of PC60BM (phenyl-C61-butyric acid methyl ester) behavior within the blend using spectroscopic or microscopic techniques.

Main Results:

• A 10-fold increase in device thermal stability was observed following the light exposure processing step.
• Enhanced device performance was noted under specific conditions, correlating with improved stability.
• Light-induced oligomerization of PC60BM was identified as the key mechanism, hindering diffusion and crystallization.

Conclusions:

• Low-level light processing is a promising, general, and cost-effective strategy to enhance the stability and performance of fullerene-based organic solar cells.
• Light-induced PC60BM oligomerization offers a pathway to overcome morphological instability challenges.
• This processing technique may have inadvertently influenced prior organic solar cell research, necessitating re-evaluation of previous findings.