Perovskite solar cells with the novel SAM. Photo: Prof. Zhu Zonglong’s research group/City University of Hong Kong.A huge step forward in the evolution of perovskite solar cells made by researchers at City University of Hong Kong (CityU) will have significant implications for renewable energy development. The CityU innovation, reported in a paper in Science, paves the way for commercializing perovskite solar cells, bringing us closer to an energy-efficient future powered by sustainable sources.
“The implications of this research are far-reaching, and its potential applications could revolutionize the solar-energy industry,” said Zonglong Zhu of the Department of Chemistry at CityU, who collaborated with Zhong’an Li at Huazhong University of Science and Technology in China.
Perovskite solar cells are a promising frontier in the solar energy landscape, known for their impressive power-conversion efficiency. However, they have one significant drawback – thermal instability, i.e. they don’t tend to perform well when exposed to high temperatures.
“Despite their high power-conversion efficiency, these solar cells are like a sports car that runs exceptionally well in cool weather but tends to overheat and underperform on a hot day,” said Zhu. “This was a significant roadblock preventing their widespread use.”
To address this problem, the team at CityU engineered a unique type of self-assembled monolayer (SAM) and anchored it on a nickel oxide surface as a charge-extraction layer.
“Our approach has dramatically enhanced the thermal robustness of the cells,” said Zhu, adding that thermal stability is a significant barrier to the commercial deployment of perovskite solar cells.
“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 1000 hours). This is a milestone achievement.”
The CityU team focused on the SAM, which is an essential part of these cells, and envisioned it as a heat-sensitive shield that needed reinforcement.
“We discovered that high-temperature exposure can cause the chemical bonds within SAM molecules to fracture, negatively impacting device performance. So our solution was akin to adding a heat-resistant armour – a layer of nickel oxide nanoparticles, topped by a SAM, achieved through an integration of various experimental approaches and theoretical calculations.”
By anchoring the SAM onto an inherently stable nickel oxide surface, the researchers enhanced the SAM's binding energy on the substrate. Also, they synthesized a new SAM molecule of their own, creating an innovative molecule that promotes more efficient charge extraction in perovskite devices.
The primary outcome of this research is the potential transformation of the solar energy landscape. By improving the thermal stability of perovskite solar cells through the innovatively designed SAMs, the team has laid the foundation for these cells to perform efficiently even in high-temperature conditions.
“This breakthrough is pivotal as it addresses a major obstacle that previously impeded wider adoption of perovskite solar cells,” explained Zhu. “Our findings could significantly broaden the utilization of these cells, pushing their application boundaries to environments and climates where high temperatures were a deterrent.
“This technology, once fully commercialized, could help decrease our dependence on fossil fuels and contribute substantially to combating the global climate crisis.”
This story is adapted from material from City University of Hong Kong, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.