Perovskite solar modules show year-long outdoor durability

Perovskite photovoltaics (PV) are poised at the brink of commercialization, yet stability remains the foremost hurdle to overcome for widespread adoption. While extensive research has addressed the degradation of perovskite PV through accelerated indoor testing, outdoor testing remains relatively underexplored and primarily focused on small cells rather than modules.

This gap underscores the urgent need to comprehensively study outdoor degradation processes. Understanding how perovskite PV modules perform under real-world environmental conditions is crucial for advancing toward commercial viability.

In our work published in ACS Energy Letters, we present a two-year outdoor evaluation of perovskite modules, shedding light on their degradation under real-world conditions. Our findings highlight a significant milestone in perovskite PV research, with the most robust module maintaining 78% of its initial performance after one year. Performance loss rates during the burn-in period were found to be about 7%–8% per month.

We provide quantitative insights into diurnal performance degradation and recovery, revealing a decrease in daytime performance and improvement overnight, with long-lasting modules experiencing degradation and recovery of up to 20%.

Analysis of diurnal current, voltage, and Fill Factor degradation shows daytime current decreases and nighttime increases, while voltage and Fill Factor exhibit opposite trends. Temperature and irradiance studies showed higher degradation and recovery rates at elevated temperatures, with minimal impact from irradiance.

Seasonal performance variations demonstrated a consistent linear diurnal degradation trend across all modules over two years, independent of environmental conditions. Furthermore, we developed and implemented a data-driven predictive model using XGBoost regression to forecast power output. This model demonstrated robust predictive capability with a normalized root mean square error (nRMSE) of 6.76% on the test set, affirming a strong correlation between predicted and actual power outputs.

We believe that this research represents a major advancement in understanding the degradation of perovskite solar modules in real-world conditions. With further improvements in the efficiency of our mini-modules, which are designed with upscaling in mind, these findings can accelerate the path toward commercialization of this promising technology.

Next, we plan to test the modules in a range of climates—from the wet and cloudy environment of Brussels to the dry heat of New Mexico, as well as moderate climates like Madrid and Freiburg. Comparing performance across these diverse locations will give us a more complete picture of how perovskite modules stand up to real-world conditions.

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