One-year perovskite solar module testing shows promising outdoor stability

<p class="p1"><span class="s1">Scientists at the European Commission Joint Research Centre tested two single-junction perovskite modules outdoors for one year and reported overall stable performance, supported by a new light-soaking preconditioning method to improve measurement reliability. While one module degraded significantly, the other maintained relatively stable efficiency with seasonal variations, highlighting the need for longer-term outdoor studies.</span></p><p>A group of scientists from the <a href="https://www.pv-magazine.com/2019/10/10/is-solar-eroding-too-much-land-the-eu-thinks-not/" rel="noopener" target="_blank">European Commission Joint Research Centre</a> (JRC) has tested the performance of two different types of single-junction perovskite solar module over a 1-year period and has concluded the testing provided &#8220;stable results.&#8221;</p>
<p>&#8220;We believe the test delivered a promising result for perovskite solar modules,&#8221; lead researcher Hanna Ellis told <strong>pv magazine</strong>. &#8220;We must be aware that all new technologies present challenges in their first deployment. For perovskite technology to be adequately judged more independent studies of outdoor performance of commercial modules are needed.&#8221;</p>
<p>&#8220;We attempted to address two issues within this article; the challenge of demonstrating that we can perform repeatable and reliable characterisation of perovskite modules, and the ability of the perovskite module to continue to perform at this level in real world conditions. We consider that the initial characterization is the most significant result for the commercialization of this technology, while the longer-term stability is very promising,&#8221; she went on to say.</p>
<p>The research team developed a new preconditioning methodology for electrical characterization. It used a light-soaking approach similar to that employed in conventional technologies, which has been shown to be suitable for commercial perovskite modules.</p>
<p>In the study &#8220;<a href="https://onlinelibrary.wiley.com/doi/10.1002/pip.70073" rel="noopener" target="_blank">Outdoor Measurements of Perovskite Modules</a>,&#8221; published in <em>Progress in Photovoltaics</em>, the researchers explained that the light soaking effect (LSE) represents the major cause affecting the thermal stability of perovskite solar cells and modules. This effect can have an impact on cell efficiency, short-circuit current and open-circuit voltage under constant illumination, when cell performance evolves with time because illumination activates several slow physical and chemical processes inside the device.</p>
<p>&#8220;The LSE phenomenon limits the reliability of the measured and modelled power output of the perovskite solar cells, and therefore, the research field is investigating mechanisms and strategies for understanding and mitigating the LSE,&#8221; the academics emphasized.</p>
<p>Testing was performed on two south-oriented glass-glass 0.7164 m² perovskite modules in outdoor environment at the European Solar Test Installation (ESTI) in Ispra, northern Italy over a one-year period from June 2024 to June 2025. The panels were deployed on fixed structures with a tilt angle of 45° and were labeled as YZ517 and YZ518. In addition, a third reference module called YZ519 was used during the measurement protocol investigations</p>
<p>Prior to outdoor installation under natural sunlight, the modules were characterized indoors under simulated illumination. For the measurements, the group used an ESTI sensor, an anemometer, temperature sensors, a pyranometer and conventional monitoring instrumentation.</p>
<p>The testing showed that the YZ518 module suffered significant degradation, with efficiency dropping below 7% by May 2025 compared to its initial indoor value. In contrast, YZ517 remains more stable, maintaining efficiency values around 12–13% in May 2025 after peaking above 15% in June–July 2024. Moreover, YZ517 was found to have a pronounced seasonal variation, with efficiency decreasing during winter and recovering in spring but, overall, it demonstrated &#8220;stable&#8221; performance and was therefore selected for further analysis as a function of irradiance, temperature, and time of day.</p>
<p>This analysis showed that, during warm summer periods following several sunny days, the YZ517 panel achieved higher efficiency values in the morning at lower temperatures compared to the afternoon at similar irradiance. However, seasonal effects were evident: on sunny days in November and December following cloudy periods, deviations occurred, with afternoon efficiency sometimes exceeding morning values at comparable irradiance.</p>
<p>&#8220;We believe that one year outdoor operation is a significant milestone, however further studies and longer-term exposure are necessary to improve our understanding and further validate the technology,&#8221; Ellis concluded, explaining that further investigation is required to fully understand the influence of irradiance, temperature, and seasonal weather conditions on perovskite solar cell performance.</p>