Why Some Perovskite Solar Materials Fall Apart Under Thermal Evaporation — And What It Means for Solar Tech
Metal halide perovskites are a class of materials that have captured huge interest in solar energy research because of their remarkable ability to convert sunlight into electricity. In less than a decade, perovskite solar cells have achieved efficiencies close to traditional silicon panels, all while potentially costing less to manufacture. But a major hurdle remains: stability. Many perovskite films degrade quickly under real-world conditions, especially during fabrication steps that use heat and vacuum. ResearchGate
A recent study published in ACS Nano explores exactly how one such common fabrication process — thermal evaporation of overlayers — can dramatically weaken perovskite materials. Thermal evaporation is a technique used to deposit thin protective or functional layers on top of a perovskite film. In this process, materials are heated until they become vapor, then condense on the surface of the perovskite. While this method is widely used because it can produce uniform, high-quality layers, the study finds that it comes with a surprising cost. ResearchGate
Researchers, including MSE Professor Dr. Steve Foulger and MSE Research Assistant Professor Dr. Brian Topper, observed that the heat and energetic environment in thermal evaporation can trigger chemical and structural changes in the perovskite. These changes lead to degradation pathways — such as breaking bonds or forming unwanted byproducts — that weaken the perovskite’s crystal structure and electronic properties. Over time, this degradation reduces performance and shortens the operational lifetime of devices like solar cells and light-emitting diodes that rely on perovskites. EurekaMag
Understanding how specific manufacturing processes impact perovskite stability is crucial for turning these promising materials into reliable commercial products. This research highlights that even standard fabrication techniques can unintentionally harm perovskites, suggesting that careful control of fabrication conditions or alternative deposition methods may be needed. ResearchGate
In short, if perovskite technologies are to reach their full potential in clean energy applications, scientists and engineers must continue refining how these materials are processed — not just what they are made of.
Citation: Bhowmik, K. K.; Ma, D.; Topper, B.; Koehler, K.; Foulger, S. H.; Xiao, H.; Zhu, L.; Zhao, L. Thermal Evaporation of Overlayers Induces Degradation of Metal Halide Perovskites. ACS NANO 2025, 19, 38428–38439.
