Breakthrough in perovskite solar cells improves efficiency and durability

New research from Northwestern engineers and chemists could bring the world closer to making solar power more reliable, efficient, and affordable, bringing renewable energy another step closer to becoming the go-to choice for homes and businesses worldwide.

Scientists in the lab of Professor Ted Sargent have developed a new method to improve the stability and efficiency of perovskite solar cells (PSCs), a promising alternative to traditional silicon solar panels. By addressing a major obstacle in the technology — poor durability — the team’s innovation could help these next-generation solar cells transition from lab prototypes to commercial reality.

At the heart of the study is a process called surface functionalization, which uses a chemical compound called 5-ammonium valeric acid iodide (5-AVAI) to enable the uniform growth of aluminum oxide (Al?O?) through atomic layer deposition. This process creates a robust barrier that suppresses halide migration — a key factor in PSC instability — by more than an order of magnitude.

Using this method, the researchers tested solar cells, and found that they retained 90 percent of their initial power conversion efficiency (PCE) after 1,000 hours of continuous operation at 55 degrees Celsius under full sunlight, compared to less than 200 hours without the barrier layer. This advancement addresses a critical barrier that has limited the commercialization of perovskite solar technology. 

Clockwise, from top left: Ted Sargent, Bin Chen, Deokjae Choi, Donghoon Shin

“We are diligently working on perovskite solar cells because they have the potential to achieve higher solar power conversion efficiency compared to existing market technologies, especially when coupled with traditional silicon panels to enhance silicon’s efficiency to significantly reduce the cost of solar electricity,” said Bin Chen, the study’s lead author and a research associate professor of chemistry in the Weinberg College of Arts and Sciences and an affiliated faculty member at the Paula M. Trienens Institute for Sustainability and Energy. “However, the commercialization of perovskite devices has been limited by issues like halide migration, which affects their stability and lifespan. Our innovation provides a solution to this challenge by enhancing the reliability of perovskite solar cells. By overcoming these technical barriers, we are opening the door to a new generation of high-efficiency, reliable solar cells that can accelerate the adoption of renewable energy globally.”

The team’s work was detailed in the paper “Carboxyl-Functionalized Perovskite Enables ALD Growth of a Compact and Uniform Ion Migration Barrier,” published January 9 in the academic journal Joule. Sargent, the Lynn Hopton Davis and Greg Davis Professor of Chemistry at the Weinberg College of Arts and Sciences and professor of electrical and computer engineering at Northwestern Engineering, is a corresponding author of the paper and directs the Trienens Institute. The work is part of the Institute’s Six Pillars of Decarbonization under the “Generate” pillar, of which Chen is the implementation lead.