Boosting high-temperature stability of perovskite solar cells

Ensuring the stability of perovskite solar cells (PSCs) at high temperatures has been a challenge, as the points of contact between the different layers (“interfaces”) are susceptible to degradation, leading to energy loss and decreased performance. Researchers have now found that they can reduce PSC degradation at high temperatures by using fluorinated aniliniums, a class of compounds used in pharmaceuticals, agrochemicals and materials science.

The researchers incorporated fluorinated aniliniums in the “interfacial passivation” step of PSC fabrication. Interfacial passivation is a technique used to enhance the stability and performance of interfaces between different layers or materials to minimise defects, reduce charge recombination, and improve overall efficiency and stability.

Adding fluorinated aniliniums enhanced the stability of PSCs by avoiding progressive ligand intercalation; this prevented the continuous penetration of ligand molecules between the layers or structures of the perovskite material, which destroys the integrity of the crystals and leads to the degradation and decreased performance of PSCs. Using this approach, the scientists achieved a quasi-steady-state power-conversion efficiency of 24.09% for inverted-structure PSCs. When testing an encapsulated PSC — a device within a protective enclosure — at a temperature of 85°C, 50% relative humidity and 1-sun illumination (the intensity of sunlight under normal, clear-sky conditions at solar noon), the device worked at its maximum power generation for 1560 hours (~65 days) while maintaining its functionality and efficiency.

The study offers a potential solution for enhancing PSC performance, durability and reliability in high-temperature environments, bringing researchers closer to the terawatt-scale deployment of this photovoltaic technology.

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