Mimicking Outdoor Ion Migration in Perovskite Solar Cells: A Forward Bias, No-Light Accelerated Aging Approach

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Perovskite solar cells (PSCs) show great promise for the photovoltaic market.
• Operational stability and accelerated aging tests are critical for PSC commercialization.
• Current aging tests primarily use illumination as the stressor.

Purpose of the Study:

• To develop a novel accelerated aging procedure for PSCs that mimics outdoor operational dynamics.
• To investigate the effects of ion migration under forward biasing and subsequent dark storage on PSC performance.
• To correlate laboratory aging results with real-world outdoor performance data.

Main Methods:

• An accelerated aging protocol involving prolonged forward biasing in the dark, followed by a dark storage (postbias rest) phase.
• Analysis of ion migration, charge transport, defect evolution, and recombination dynamics during aging.
• Comparison of aging results with 20-month outdoor operational data from PSCs in Berlin, Germany.

Main Results:

• Forward biasing induced ion migration, hindering charge transport and causing defect growth, which partially recovered during the postbias rest phase.
• The postbias rest phase led to increased recombination due to ion redistribution.
• Outdoor PSC performance dynamics over 20 months mirrored the observed aging phases, with high irradiance/temperature correlating to forward bias and low irradiance/temperature to postbias rest.

Conclusions:

• A novel dark-based accelerated aging method effectively simulates ion migration-induced degradation in PSCs.
• This procedure accurately mimics outdoor operational degradation patterns without the need for illumination.
• The findings enable more relevant and efficient stability assessments for perovskite solar cells.