Researchers at Hong Kong’s City University have developed a method to enhance the thermal robustness of perovskite solar cells, making this a significant step in their evolution and application.

While perovskite solar cells are known for their impressive power conversion efficiency,  they lack thermal stability, which means they do not perform well when exposed to high temperatures. This emerges as a challenge because the primary application of these cells is in solar energy technologies.

Motivated to solve the thermal instability, the team focused on the self-assembled monolayer (SAM), an essential part of these cells, and envisioned it as a heat-sensitive shield that needed reinforcement.

The researchers enhanced SAM’s binding energy on the substrate by anchoring the SAM onto an inherently stable nickel oxide surface. The team also synthesized a new SAM molecule of its own, creating an innovative molecule that promotes more efficient charge extraction in perovskite devices.

“By introducing a thermally robust charge extraction layer, our improved cells retain over 90% of their efficiency, boasting an impressive efficiency rate of 25.6%, even after operated under high temperatures, around (65℃) for over 1,000 hours. This is a milestone achievement,” said Zhu, a professor at the university.

This approach, reported in the journal Science, has allowed the cells to be more commercially viable, ensuring their widespread usage in heralding an energy-efficient future.

Zhu said the findings could significantly broaden the utilization of these cells, pushing their application boundaries to environments and climates where high temperatures were a deterrent.

As the commercialization of these cells helps reduce the dependence on fossil fuels, there have been several developments on this front. Earlier this year, the National Renewable Energy Laboratory found a way to produce perovskite solar cells that simplified manufacturing and potentially reduced costs.

Researchers at Swansea University also devised a low-cost and scalable carbon ink formulation that allowed for widespread manufacturing and production of these cells.