Additive-Assisted Annealing Process Significantly Boosts Perovskite Solar Cell Stability and Efficiency

Bioengineer.org USA

Overview

Researchers have developed a novel annealing process that incorporates 1,4-butanesultam as an additive into perovskite precursor solutions, significantly enhancing device performance. This additive effectively alleviates residual strain within the perovskite film, improving crystal quality and boosting power conversion efficiency to 26.79%. Devices demonstrated exceptional stability, retaining 95% of their initial efficiency after 1,000 hours of continuous ISOS-V-2 testing and showing negligible degradation after 1,500 hours of diurnal cycling, marking a major advance for long-term perovskite solar cell viability.

In Depth

Addressing Perovskite Solar Cell Stability Challenges

Perovskite solar cells have achieved power conversion efficiencies (PCEs) comparable to, and in some cases surpassing, those of conventional silicon-based devices. However, their widespread practical application has been largely hampered by insufficient long-term stability, particularly under environmental stresses such as heat, light, and humidity. A critical issue stems from the residual strain that often develops within the perovskite film during conventional fabrication processes. This internal stress can lead to the formation of defects and degradation over time, limiting the operational lifespan of the devices.

Innovative Annealing with 1,4-Butanesultam Additive

To overcome this, recent research has introduced an innovative strategy involving the incorporation of a small amount of an organic additive, 1,4-butanesultam, into the perovskite precursor solution, followed by an optimized annealing (thermal treatment) process. This additive plays a crucial role in influencing the perovskite crystallization mechanism, leading to several key benefits:

• Alleviation of Residual Strain: 1,4-butanesultam helps mitigate the strain within the perovskite lattice during crystallization, promoting the formation of a more uniform and defect-free film. This reduction in internal stress significantly improves the device’s resilience to external environmental factors.
• Enhanced Crystal Quality: The additive also contributes to a passivation effect at the grain boundaries, reducing charge recombination sites. This results in improved charge separation and transport efficiency, leading to higher open-circuit voltage (V_oc) and fill factor (FF).
• Achieving High Efficiency: Perovskite solar cells fabricated using this additive-assisted annealing method achieved an impressive PCE of 26.79%, a remarkably high value for single-junction perovskite devices.

Demonstrated Long-Term Stability and Future Prospects

The developed devices exhibited outstanding stability performance, evaluated according to the international ISOS-V-2 protocol:

• Continuous Operation Stability: The cells maintained 95% of their initial efficiency after 1,000 hours of continuous operation under simulated sunlight, representing a significant step towards practical, long-lived devices.
• Cycling Stability: Furthermore, negligible degradation was observed after 1,500 hours of daily cycling tests, which simulate the diurnal variations in temperature and light exposure. This outcome underscores the device’s reliability under fluctuating outdoor conditions.

This additive-assisted annealing technology, utilizing 1,4-butanesultam, offers a powerful solution to the critical challenge of long-term stability for perovskite solar cells, a major barrier to their commercialization. Future work will focus on scaling this technology for large-area applications and verifying its cost-effectiveness, positioning it as a potential game-changer for the next-generation solar energy market.