Researchers identify main source of wide-bandgap solar perovskite degradation
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Summary
Scientists in Belgium have investigated how perovskite absorbers used in solar cell degrade under three different stress test types and have found that the interface between the perovskite layer and the electron transport layer suffers from weak thermomechanical stability, which creates the conditions for performance losses.
<p class="p1"><span class="s1">Scientists in Belgium have investigated how perovskite absorbers used in solar cell degrade under three different stress test types and have found that the interface between the perovskite layer and the electron transport layer suffers from weak thermomechanical stability, which creates the conditions for performance losses.</span></p><p>Researchers from <a href="https://www.pv-magazine.com/2023/11/29/imec-integrates-silicon-heterojunction-solar-cells-into-curved-surfaces/" rel="noopener" target="_blank">imec</a>, <a href="https://www.pv-magazine.com/2024/02/06/the-impact-of-climate-based-pv-panel-degradation-rates-on-inverters/" rel="noopener" target="_blank">Hasselt University</a>, and <a href="https://www.pv-magazine.com/2025/09/11/pv-industry-could-account-for-40-of-global-silver-demand-by-2030/" rel="noopener" target="_blank">Ghent University</a> in Belgium have investigated the impact of light and heat on the degradation of wide-bandgap perovskite solar cells and have found that the devices' charge transport layers are the main source of performance losses.</p>
<p>Their analysis focused on perovskite materials with an energy bandgap of 1.68 eV and the comparison of their performance with perovskites with an energy bandgap of 1.61 eV.</p>
<p>“Wide bandgap perovskites typically face poor stability under light and at elevated temperatures,” they explained. “This is because of the phase segregation mechanism, in which bromide and iodide species that constitute part of the perovskite crystal separate in distinct phases, therefore hindering the layer stability.”</p>
<p>For their assessment, the scientists used three standardized accelerated stress tests derived from the International Summit on Organic Photovoltaic Stability (ISOS) protocols that are known as ISOS-L1 (prolonged exposure to light), ISOS-D2 (thermal stress in the dark), and ISOS-L2 (thermal stress under light).</p>
<p>They also used an electrical characterization toolbox combining current-voltage (IV), photoluminescence (PL) and capacity-frequency (C-f) analysis. The solar cells were exposed to 1 sun light intensity and an elevated temperature of 60 C.</p>
<p>The tests showed that the main source of degradation in all analyzed perovskite solar cells is the interface between the perovskite absorber and the electron transport material (ETL), due to “weak” thermomechanical stability. In particular, the researchers found that the dielectric permittivity of the perovskite was compromised by the degradation caused by the combined effect of heat and light.</p>
<p>“From this analysis, it emerged that different degradation modes are observed in different stressing conditions, emphasizing that ‘perovskite stability' may not be an absolute concept,” the researchers stressed. “This important finding emphasizes the role of heat on the phase segregation process and on the degradation of wide bandgap perovskites under operational conditions, which was overlooked in many previous studies.”</p>
<p>Their findings can be found in the study “<a href="https://iopscience.iop.org/article/10.1088/2752-5724/ae01c1" rel="noopener" target="_blank">In-Depth Study of Degradation in Scalable Wide Bandgap Perovskite Cells</a>,” published in <em>Materials Futures</em>. Looking forward, the team said it wants to investigate nanoscale-level degradation in different stressing conditions and conduct more tests in a wider range of stressing conditions, “potentially leading to the discovery of new degradation modes.”</p>