> Quick answer: The provided research does not definitively answer how UV exposure affects the IP65 integrity of polycarbonate solar lamp housings after five years in Romania. However, it suggests that standard lab tests may overestimate real-world degradation due to a recoverable „metastable resilience” effect [6][8][22][23].
While extensive research has been conducted on the UV-induced degradation of photovoltaic (PV) modules, the specific impact on polycarbonate housings and their IP65 integrity in Romanian conditions remains unclear. This article delves into what we do know about UV exposure’s effects on solar equipment and how these insights might apply to solar lamps used in Romania.
Understanding UV Degradation in Solar Modules
UV degradation is a significant concern for the longevity of PV modules, including those used in solar lamps. Research shows that UV-induced degradation (UVID) varies significantly based on geographic location and system configuration [2][9][12]. For example, areas with high irradiance, such as Dubai, experience 5.4 times more UV exposure than Berlin [2][9][12]. While Romania’s temperate climate places it in an intermediate category for UV levels, the cumulative effect over five years would still be substantial.
Comparative UV Exposure and Module Degradation
| Region/Location | UV Irradiance (kWh/m²) | Notes |
|––––––|––––––––|––-|
| Dubai | High | Very high exposure [2][9] |
| Berlin | Low | Moderate exposure [2][12] |
| Romania | Intermediate | Temperate climate, moderate to high exposure over time |
Laboratory vs. Real-World Degradation
One of the most surprising findings is that standard laboratory UV tests may significantly overestimate real-world degradation for TOPCon modules [6][8][23]. These lab tests typically indicate performance losses of up to 5%, but these losses are often reversed or reduced after post-UV stabilization under sunlight, a phenomenon known as „metastable resilience” or „self-healing” [22][23].
Testing Standards and Self-Healing Properties
Current testing standards require modules to withstand 15 kWh/m² of UV exposure before certification [10]. However, this may be too aggressive since many modern modules show signs of self-recovery when exposed to sunlight after UV degradation [6][8][23]. This „dark storage effect” leads to a critical flaw in testing protocols: they fail to simulate the natural recovery process that occurs in real-world installations.
Material Design and Degradation Mitigation
The sources also highlight that material design plays a crucial role in mitigating UV damage. For instance, dual-layer encapsulation strategies combining UV-downshifting and UV-blocking layers have shown to improve stability, retaining over 98% of initial performance after 120 kWh/m² of UV exposure [25]. This suggests that advancements in materials can significantly reduce the impact of UV degradation.
Impact on Polycarbonate Housings
Despite these insights into module degradation, there is a critical gap in understanding how UV exposure affects polycarbonate housings. IP65 integrity depends on both the housing material’s resistance to environmental stress and the sealing system’s ability to prevent dust and water ingress [13]. While high UV exposure can accelerate backsheet degradation in desert environments, no specific data addresses polycarbonate degradation or its impact on sealing performance over five years.
Key Takeaways
- Standard lab tests may overestimate real-world UV-induced degradation due to the „metastable resilience” effect.
- Material design and dual-layer encapsulation strategies are effective in mitigating UV damage.
- There is a critical gap in understanding how UV exposure affects polycarbonate housings, particularly their impact on IP65 integrity.
Frequently Asked Questions
[
{
„q”: „How does UV exposure affect solar panel performance over time?”,
„a”: „UV-induced degradation can vary significantly based on geographic location and system configuration. High-irradiance regions experience more rapid degradation [2][9].”
},
{
„q”: „What is the ‘metastable resilience’ effect observed in TOPCon modules?”,
„a”: „The ‘metastable resilience’ or ‘self-healing’ effect occurs when UV exposure induces temporary degradation that can be reversed through light soaking after UV stabilization [22][23].”
},
{
„q”: „How do testing standards account for real-world UV exposure?”,
„a”: „Current testing standards overestimate real-world performance losses by failing to simulate natural recovery processes, leading to the need for updated protocols that include post-UV stabilization procedures [5][16][23].”
}
]
References
- [2] Solving_the_UV_problem_of_n-type_solar_-_pv_magazine_Global__bfc868bc — magazine
source passage
got from the research community suggests that for these more delicate cell structures, UV is a more significant factor,” said Erion-Lorico. “It was reintroduced into extended reliability tests, including Kiwa PVEL’s PQP.” Devising accelerated tests to accurately predict how UV light will affect PV modules over 30 years in the field poses a significant challenge. Tests can currently accelerate by a factor of around five – meaning that one full year in a UV test chamber would represent five years installed in the field, according to Erion-Lorico’s estimates. “It’s hard to accelerate UV testing much more than we’re already doing and still have the results representative to field conditions, not just frying the module,” he explained. Added complexity also comes from the very different levels of UV exposure modules can experience, depending on where they are installed. Data from the Middle East Solar Industry Association indicate that a module installed in Dubai receives 5.4 times the UV exposure of one installed in Berlin, for example. RETC Chief Executive Cherif Kedir said, in a September 2024 pv magazine webinar, that UV degradation is a cumulative effect and even where testing has shown a module is susceptible to UV damage, longer term observation is needed to indicate the progression over time. “We’re trying to perform long term UV exposures to see if [a PV module] keeps degrading every year,” said Kedir, adding that another unknown is whether even low-level UV degradation co
- [5] UV-induced_Degradation_Comparative_Analysis_of_PV_Module__8e39c653 — authority
source passage
# UV-induced Degradation: Comparative Analysis of PV Module Testing and Stabilization Procedures Against Outdoor Behavior Source: Blog/Web URL: https://publica.fraunhofer.de/entities/publication/d003192d-eeaf-487a-bc2a-5d0543d40cc9 Author: Gebhardt; Paul; Rivera Aguilar; Mariella Josefina; Fokuhl; Esther; Reise; Christian; Frey; Hyrie; Schnabel; Erdmut; Pander; Matthias; Hädrich; Ingrid Date: 2026-03-27 Options 2026 Journal Article Title UV-induced Degradation: Comparative Analysis of PV Module Testing and Stabilization Procedures Against Outdoor Behavior Abstract UV-induced degradation (UVID) represents a critical reliability concern for TOPCon-based photovoltaic modules, yet the correlation between laboratory testing and real-world performance remains poorly understood. This study validates indoor UVID testing protocols against outdoor degradation through comprehensive analysis of four module types across five outdoor sites with up to 28 months of field exposure. We demonstrate that post-UV stabilization via brief light soaking is essential for accurate laboratory assessment, effectively reversing dark storage effects that otherwise confound UVID measurements. Comparative analysis reveals a strong relation between indoor testing (following IEC 61215-2:2021 MQT10) and outdoor degradation when proper stabilization is applied, with indoor slightly but consistently overestimating field degradation for TOPCon modules. Notably, while dark storage effects cause significant power l
- [6] Fraunhofer_ISE_evaluates_common_UV_tests_for_TOPCon_modules_for__b48bffd7 — authority
source passage
it remains necessary to further analyze the phenomenon to more accurately predict the long-term effects of UV-induced degradation on module yield.” The investigations by the Fraunhofer ISE research team indicate that UV irradiation during the tests destabilizes the modules to such an extent that they lose a great deal of efficiency during dark storage after UV exposure. Subsequent irradiation with sunlight, on the other hand, leads to a significant recovery effect. Field tests at the Fraunhofer ISE Outdoor Performance Lab with TOPCon modules and analyses of 'field returns' at the institute's CalLab PV Modules, indicate that this stabilization process provides degradation measurements that are significantly closer to the values measured in practice. Some PV modules showed hardly any degradation after UV testing at 60 kilowatt hours per square meter, which roughly corresponds to the UV exposure in one year in Germany, and subsequent stabilization under sunlight. Other modules still showed significant power losses of up to 5 percent even after stabilization. Overall, however, the degradation is significantly less drastic than the standard UV tests suggest. Laboratory UV tests simulate the natural UV radiation to which PV modules are exposed in the field and on roofs, but significantly increase the intensity of the irradiation to accelerate aging and thus be able to predict long-term power losses. Last modified:
- [8] Current_UV_tests_overestimate_TOPCon_solar_module_degradation__665318a2 — magazine
source passage
real-world outcomes. Some modules showed little to no degradation after 60 kWh/m² of UV exposure – roughly equivalent to one year in Germany – and subsequent stabilization under sunlight. Others still showed performance declines of up to 5% post-stabilization. Overall, degradation was significantly lower than suggested by standard UV tests, said Fraunhofer ISE.
- [9] UNSW_study_finds_tracker-based_PV_systems_-_pv_magazine_Global__7e8abfb2 — magazine
source passage
installations. Over the course of a typical project lifetime, this difference can accumulate to several percentage points of additional power loss, directly impacting the economics and long-term performance of the PV system. The study also showed that identical PV modules can degrade at markedly different rates depending on their installation location. The key factors driving this variability include UV irradiance, temperature, humidity, and atmospheric conditions such as ozone levels, aerosols, and cloud cover. Among the most challenging environments are tropical and desert regions, where high UV exposure combines with intense thermal and environmental stress, accelerating module degradation. “Current standards significantly underestimate real-world UV exposure, in some cases by orders of magnitude relative to lifetime conditions,” Hoex stressed. “UV exposure varies significantly with location and system configuration, with tracking systems experiencing up to around two times higher degradation rates in high-irradiance regions. In arid and tropical climates, UV-induced degradation can reach about 0.25–0.35%/year, contributing substantially to long-term performance loss.” The novel high-precision model to estimate UV radiation in PV systems was presented in the paper “Closing the UV-Induced Photodegradation Gap Through Global Scale Modeling of Fixed Tilt and Tracking Photovoltaic Systems,” pubished in the IEEE Journal of Photovoltaics. “This work forms part of our group’s bro
- [10] UNSW_Next-gen_solar_module_could_degrade_faster_than_expected__bfa0f162 — authority
source passage
degradation rates of around 0.5 per cent per year, often assuming a steady, linear decline in performance. However, the UNSW study suggests that degradation may not follow a strictly linear pattern and that UV exposure could account for a significant fraction of total performance loss, particularly in high-irradiance environments where atmospheric conditions concentrate ultraviolet radiation on panel surfaces. “That number might not sound dramatic at first,” Dr Poddar said. “But when you quantify it over 20 years, it accumulates quite quickly.” The implications extend directly to project economics and warranty structures, particularly as previous UNSW research has shown that up to one-fifth of solar PV modules degrade 1.5 times faster than average. The team’s global UV mapping provides a mechanism to identify which geographic regions and mounting configurations face the highest risk of accelerated degradation, enabling more accurate financial modelling and warranty risk assessment before deployment. Testing standards lag behind field conditions Current international standards require solar modules to pass a UV test equivalent to 15 kilowatt-hours per square metre before receiving certification for deployment. This reaffirms some of the key messages UNSW scientists recently told PV Tech Premium regarding UV testing protocols for TOPCon cells. The UNSW research reveals a disconnect between this testing threshold and actual field conditions, particularly in high-irradiance regio
- [12] UNSW_study_finds_tracker-based_PV_systems_-_pv_magazine_Global__7e8abfb2 — magazine
source passage
# UNSW study finds tracker-based PV systems experience higher UV degradation than fixed-tilt arrays – pv magazine Global Source: Blog/Web URL: https://www.pv-magazine.com/2026/04/02/unsw-study-finds-tracker-based-pv-systems-experience-higher-uv-degradation-than-fixed-tilt-arrays/ Author: Emiliano Bellini Date: 2026-04-02 UNSW study finds tracker-based PV systems experience higher UV degradation than fixed-tilt arrays Utraviolet (UV) radiation has been long recognized as a key driver of PV module degradation. This factor, however, is significantly underestimated in current testing standards, particularly for modern system designs and high-irradiance regions. With this in mind, a group of researchers at the University of New South Wales (UNSW) in Australia has developed a high-precision global UV irradiance model on tilted surfaces, capturing the impact of system design, climate, and atmospheric conditions. “Our new model demonstrates that identical module technologies degrade differently depending on deployment location, highlighting the need for climate-specific reliability assessment,” corresponding author Bram Hoex told pv magazine. “It also offers a pathway to move beyond generic accelerated testing toward regionally relevant degradation modeling and qualification protocols.” The researchers highlighted that global UV irradiance can range from below 30 W/m² in high-latitude regions to over 80 W/m² in deserts and dry climates. In some locations, the UV dose specified in the
- [13] A_closer_look_at_backsheet_degradation_in_desert_enviromnents__48c7ab75 — magazine
source passage
# A closer look at backsheet degradation in desert enviromnents – pv magazine Global Source: Blog/Web URL: https://www.pv-magazine.com/2024/09/19/a-closer-look-at-backsheet-degradation-in-desert-enviromnents/ Author: Emiliano Bellini Date: 2024-09-19 Researchers at the Hamad Bin Khalifa University (HBKU) in Qatar have conducted an assessment of the degradation of polyamide (PA) and polyethylene terephthalate (PET) backsheets used in PV modules installed in desert climates, where solar irradiance and ultraviolet (UV) irradiance are approximately 50% higher compared to non-desert environments. The analysis focused on backsheet crack initiation, propagation, chalking, and delamination. “In this study, extensive investigation of PA and PET chalking powder has been carried out to get a better understanding of the failure mechanism and the powder composition,” the researchers specified. The tests were carried out at HBKU’s Outdoor Test Facility (OTF) in Doha, where in summer months the monthly average ambient temperature is 31 C, the average module temperature is 38 C, and relative humidity (RH) is around 50%, while in winter months these values are 40 C, 70 C, and 65%, respectively. “Further, at the OTF, a high surface albedo of 40% was measured,” the group explained. “This high albedo value is expected to enhance the UV irradiance received on the PV module backsheet due to multiple scattering of the reflected irradiance.” Ground-mounted irradiance sensors were used to measure sol
- [16] A_better_understanding_of_UV_degradation_-_pv_magazine_Global__cf8fb0c2 — magazine
source passage
with the way the lab test is accelerated – that it’s maybe too strong to give an accurate representation of what happens in the field? Not quite, although that is a topic we are still investigating. There are no good studies comparing indoor and outdoor degradation yet, so for now we have to assume that the acceleration, the higher light intensity, will cause the same degradation as over a longer time with lower intensity. On the one hand we have seen cases of UV induced degradation in the field. On the other, looking at the number of module types that show this UV degradation in the lab, we would expect more cases outdoors. There is uncertainty when it comes to comparing indoor and outdoor results. But independently of this, we know that indoor results are affected by this additional dark storage effect. Does this point to a need for an update to the standard testing procedures? There is a definite need to add light soaking or another stabilization procedure after the UV test. It’s under discussion if we can use the exact same procedure of light soaking that is defined in the standard, or if we have to define a special light soaking that is applied after UV. Changes to the UV test itself may also be needed. For example, the operating point, if modules are in short circuit or open circuit, or in maximum power point tracking, in the UV chamber. There is still data being collected on these issues. Is this degradation issue confined to tunnel oxide passivated contact (TOPCon) mo
- [22] TOPCon_solar_modules_show_self-healing_under_UV_stress__62706250 — magazine
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# TOPCon solar modules show self-healing under UV stress – pv magazine Global Source: Blog/Web URL: https://www.pv-magazine.com/2026/03/10/topcon-solar-modules-show-uv-induced-degradation-recovery-study-finds/ Author: Emiliano Bellini Date: 2026-03-10 A group of researchers from China’s Nanchang University and solar module manufacturer Trina Solar have conducted a series of experiments to assess the impact of ultraviolet-induced degradation (UVID) on the performance of tunnel oxide passivating contact (TOPCon) solar modules and have found that this panel type can offer “metastable resilience” in real-world operation. “Our lab-to-field studies confirm that UVID in TOPCon is a light-recoverable metastable effect with no impact on real-world energy production,” the research’s lead author, Zhiwei Li, told pv magazine. “This is critical for improving investor confidence and bankability, and establishes a clear reliability understanding for the industry.” The researchers conducted UV accelerated aging tests on TOPCon solar cells using a HY-UV-4225 chamber equipped with a metal halide lamp emitting in the 280–400 nm range. During these experiments, the UV intensity was set to 180 W/m², and the module temperature was maintained at 60-65 C, with the samples being placed under short-circuit conditions in a chamber at 50-60 C and exposed to a cumulative irradiation dose of 2 kWh/m² from an 800 W/m² light source spanning 300–1200 nm. The cells were sandwiched between standard module glas
- [23] Current_UV_tests_overestimate_TOPCon_solar_module_degradation__665318a2 — magazine
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# Current UV tests overestimate TOPCon solar module degradation – pv magazine Global Source: Blog/Web URL: https://www.pv-magazine.com/2025/04/09/current-uv-tests-overestimate-topcon-solar-module-degradation/ Author: Ralph Diermann Date: 2025-04-09 From pv magazine Germany In 2024, researchers at Fraunhofer ISE analyzed the stability of TOPCon, passivated emitter and rear cell (PERC), and heterojunction solar cells under UV irradiation and found that all three cell technologies can suffer significant losses in implied voltage and efficiency. Practical experience has confirmed this finding. With that in mind, other Fraunhofer ISE researchers assessed the validity of standard UV testing methods for TOPCon modules. The result – surprising at first glance – is that conventional UV tests can significantly exaggerate the degradation effect. In these lab tests, experts simulate the natural UV exposure photovoltaic modules face in the field and on rooftops. They increase the irradiation intensity to accelerate aging and estimate long-term performance losses. Testing limits Fraunhofer ISE said modules must be stabilized after testing to produce results that reflect real-world degradation more accurately. Only then can researchers distinguish between UV-sensitive and more stable module types for comparable evaluations. Scientists attributed this to the metastable behavior of commercial TOPCon modules, prompting a reassessment of test procedures and additional field testing. “Many modul
- [25] Dual-Layer_Encapsulation_Mitigates_UVID_In_Lightweight_Solar__2b77dacc — magazine
source passage
to this degradation mechanism. This indicates that reliability challenges in lightweight module designs are not limited to the solar cell itself, but also extend to module materials and interconnection systems. To improve long-term UV stability, the team proposed a dual-layer encapsulation structure combining a UV-downshifting layer with an additional UV-blocking encapsulant. In this configuration, the upper downshifting layer converts part of the incoming UV radiation into usable visible light, while the secondary UV-filtering layer absorbs residual short-wavelength photons before they reach the SHJ passivation stack. The combined encapsulation structure demonstrated substantially improved stability during accelerated UV aging. The configuration combining UV-downshifting EVA with the stronger UV-blocking encapsulant retained more than 98% of its initial performance after exposure to 120 kWh/m² of UV radiation. According to the researchers, the dual-layer module also maintained significantly higher post-aging efficiency than modules using conventional UV-transmitting encapsulation. The findings were published in the paper titled Mitigation of UV-Induced Degradation in Lightweight SHJ Solar Modules via a UV-Downshifting Encapsulation Strategy in Progress in Photovoltaics: Research and Applications. TaiyangNews has released 5 editions of its Backsheets and Encapsulation Market Survey so far and is currently preparing the 6th edition. Stay tuned for the latest updates on encapsu
got from the research community suggests that for these more delicate cell structures, UV is a more significant factor,” said Erion-Lorico. “It was reintroduced into extended reliability tests, including Kiwa PVEL’s PQP.” Devising accelerated tests to accurately predict how UV light will affect PV modules over 30 years in the field poses a significant challenge. Tests can currently accelerate by a factor of around five – meaning that one full year in a UV test chamber would represent five years installed in the field, according to Erion-Lorico’s estimates. “It’s hard to accelerate UV testing much more than we’re already doing and still have the results representative to field conditions, not just frying the module,” he explained. Added complexity also comes from the very different levels of UV exposure modules can experience, depending on where they are installed. Data from the Middle East Solar Industry Association indicate that a module installed in Dubai receives 5.4 times the UV exposure of one installed in Berlin, for example. RETC Chief Executive Cherif Kedir said, in a September 2024 pv magazine webinar, that UV degradation is a cumulative effect and even where testing has shown a module is susceptible to UV damage, longer term observation is needed to indicate the progression over time. “We’re trying to perform long term UV exposures to see if [a PV module] keeps degrading every year,” said Kedir, adding that another unknown is whether even low-level UV degradation co
# UV-induced Degradation: Comparative Analysis of PV Module Testing and Stabilization Procedures Against Outdoor Behavior Source: Blog/Web URL: https://publica.fraunhofer.de/entities/publication/d003192d-eeaf-487a-bc2a-5d0543d40cc9 Author: Gebhardt; Paul; Rivera Aguilar; Mariella Josefina; Fokuhl; Esther; Reise; Christian; Frey; Hyrie; Schnabel; Erdmut; Pander; Matthias; Hädrich; Ingrid Date: 2026-03-27 Options 2026 Journal Article Title UV-induced Degradation: Comparative Analysis of PV Module Testing and Stabilization Procedures Against Outdoor Behavior Abstract UV-induced degradation (UVID) represents a critical reliability concern for TOPCon-based photovoltaic modules, yet the correlation between laboratory testing and real-world performance remains poorly understood. This study validates indoor UVID testing protocols against outdoor degradation through comprehensive analysis of four module types across five outdoor sites with up to 28 months of field exposure. We demonstrate that post-UV stabilization via brief light soaking is essential for accurate laboratory assessment, effectively reversing dark storage effects that otherwise confound UVID measurements. Comparative analysis reveals a strong relation between indoor testing (following IEC 61215-2:2021 MQT10) and outdoor degradation when proper stabilization is applied, with indoor slightly but consistently overestimating field degradation for TOPCon modules. Notably, while dark storage effects cause significant power l
it remains necessary to further analyze the phenomenon to more accurately predict the long-term effects of UV-induced degradation on module yield.” The investigations by the Fraunhofer ISE research team indicate that UV irradiation during the tests destabilizes the modules to such an extent that they lose a great deal of efficiency during dark storage after UV exposure. Subsequent irradiation with sunlight, on the other hand, leads to a significant recovery effect. Field tests at the Fraunhofer ISE Outdoor Performance Lab with TOPCon modules and analyses of 'field returns' at the institute's CalLab PV Modules, indicate that this stabilization process provides degradation measurements that are significantly closer to the values measured in practice. Some PV modules showed hardly any degradation after UV testing at 60 kilowatt hours per square meter, which roughly corresponds to the UV exposure in one year in Germany, and subsequent stabilization under sunlight. Other modules still showed significant power losses of up to 5 percent even after stabilization. Overall, however, the degradation is significantly less drastic than the standard UV tests suggest. Laboratory UV tests simulate the natural UV radiation to which PV modules are exposed in the field and on roofs, but significantly increase the intensity of the irradiation to accelerate aging and thus be able to predict long-term power losses. Last modified:
real-world outcomes. Some modules showed little to no degradation after 60 kWh/m² of UV exposure – roughly equivalent to one year in Germany – and subsequent stabilization under sunlight. Others still showed performance declines of up to 5% post-stabilization. Overall, degradation was significantly lower than suggested by standard UV tests, said Fraunhofer ISE.
installations. Over the course of a typical project lifetime, this difference can accumulate to several percentage points of additional power loss, directly impacting the economics and long-term performance of the PV system. The study also showed that identical PV modules can degrade at markedly different rates depending on their installation location. The key factors driving this variability include UV irradiance, temperature, humidity, and atmospheric conditions such as ozone levels, aerosols, and cloud cover. Among the most challenging environments are tropical and desert regions, where high UV exposure combines with intense thermal and environmental stress, accelerating module degradation. “Current standards significantly underestimate real-world UV exposure, in some cases by orders of magnitude relative to lifetime conditions,” Hoex stressed. “UV exposure varies significantly with location and system configuration, with tracking systems experiencing up to around two times higher degradation rates in high-irradiance regions. In arid and tropical climates, UV-induced degradation can reach about 0.25–0.35%/year, contributing substantially to long-term performance loss.” The novel high-precision model to estimate UV radiation in PV systems was presented in the paper “Closing the UV-Induced Photodegradation Gap Through Global Scale Modeling of Fixed Tilt and Tracking Photovoltaic Systems,” pubished in the IEEE Journal of Photovoltaics. “This work forms part of our group’s bro
degradation rates of around 0.5 per cent per year, often assuming a steady, linear decline in performance. However, the UNSW study suggests that degradation may not follow a strictly linear pattern and that UV exposure could account for a significant fraction of total performance loss, particularly in high-irradiance environments where atmospheric conditions concentrate ultraviolet radiation on panel surfaces. “That number might not sound dramatic at first,” Dr Poddar said. “But when you quantify it over 20 years, it accumulates quite quickly.” The implications extend directly to project economics and warranty structures, particularly as previous UNSW research has shown that up to one-fifth of solar PV modules degrade 1.5 times faster than average. The team’s global UV mapping provides a mechanism to identify which geographic regions and mounting configurations face the highest risk of accelerated degradation, enabling more accurate financial modelling and warranty risk assessment before deployment. Testing standards lag behind field conditions Current international standards require solar modules to pass a UV test equivalent to 15 kilowatt-hours per square metre before receiving certification for deployment. This reaffirms some of the key messages UNSW scientists recently told PV Tech Premium regarding UV testing protocols for TOPCon cells. The UNSW research reveals a disconnect between this testing threshold and actual field conditions, particularly in high-irradiance regio
# UNSW study finds tracker-based PV systems experience higher UV degradation than fixed-tilt arrays – pv magazine Global Source: Blog/Web URL: https://www.pv-magazine.com/2026/04/02/unsw-study-finds-tracker-based-pv-systems-experience-higher-uv-degradation-than-fixed-tilt-arrays/ Author: Emiliano Bellini Date: 2026-04-02 UNSW study finds tracker-based PV systems experience higher UV degradation than fixed-tilt arrays Utraviolet (UV) radiation has been long recognized as a key driver of PV module degradation. This factor, however, is significantly underestimated in current testing standards, particularly for modern system designs and high-irradiance regions. With this in mind, a group of researchers at the University of New South Wales (UNSW) in Australia has developed a high-precision global UV irradiance model on tilted surfaces, capturing the impact of system design, climate, and atmospheric conditions. “Our new model demonstrates that identical module technologies degrade differently depending on deployment location, highlighting the need for climate-specific reliability assessment,” corresponding author Bram Hoex told pv magazine. “It also offers a pathway to move beyond generic accelerated testing toward regionally relevant degradation modeling and qualification protocols.” The researchers highlighted that global UV irradiance can range from below 30 W/m² in high-latitude regions to over 80 W/m² in deserts and dry climates. In some locations, the UV dose specified in the
# A closer look at backsheet degradation in desert enviromnents – pv magazine Global Source: Blog/Web URL: https://www.pv-magazine.com/2024/09/19/a-closer-look-at-backsheet-degradation-in-desert-enviromnents/ Author: Emiliano Bellini Date: 2024-09-19 Researchers at the Hamad Bin Khalifa University (HBKU) in Qatar have conducted an assessment of the degradation of polyamide (PA) and polyethylene terephthalate (PET) backsheets used in PV modules installed in desert climates, where solar irradiance and ultraviolet (UV) irradiance are approximately 50% higher compared to non-desert environments. The analysis focused on backsheet crack initiation, propagation, chalking, and delamination. “In this study, extensive investigation of PA and PET chalking powder has been carried out to get a better understanding of the failure mechanism and the powder composition,” the researchers specified. The tests were carried out at HBKU’s Outdoor Test Facility (OTF) in Doha, where in summer months the monthly average ambient temperature is 31 C, the average module temperature is 38 C, and relative humidity (RH) is around 50%, while in winter months these values are 40 C, 70 C, and 65%, respectively. “Further, at the OTF, a high surface albedo of 40% was measured,” the group explained. “This high albedo value is expected to enhance the UV irradiance received on the PV module backsheet due to multiple scattering of the reflected irradiance.” Ground-mounted irradiance sensors were used to measure sol
with the way the lab test is accelerated – that it’s maybe too strong to give an accurate representation of what happens in the field? Not quite, although that is a topic we are still investigating. There are no good studies comparing indoor and outdoor degradation yet, so for now we have to assume that the acceleration, the higher light intensity, will cause the same degradation as over a longer time with lower intensity. On the one hand we have seen cases of UV induced degradation in the field. On the other, looking at the number of module types that show this UV degradation in the lab, we would expect more cases outdoors. There is uncertainty when it comes to comparing indoor and outdoor results. But independently of this, we know that indoor results are affected by this additional dark storage effect. Does this point to a need for an update to the standard testing procedures? There is a definite need to add light soaking or another stabilization procedure after the UV test. It’s under discussion if we can use the exact same procedure of light soaking that is defined in the standard, or if we have to define a special light soaking that is applied after UV. Changes to the UV test itself may also be needed. For example, the operating point, if modules are in short circuit or open circuit, or in maximum power point tracking, in the UV chamber. There is still data being collected on these issues. Is this degradation issue confined to tunnel oxide passivated contact (TOPCon) mo
# TOPCon solar modules show self-healing under UV stress – pv magazine Global Source: Blog/Web URL: https://www.pv-magazine.com/2026/03/10/topcon-solar-modules-show-uv-induced-degradation-recovery-study-finds/ Author: Emiliano Bellini Date: 2026-03-10 A group of researchers from China’s Nanchang University and solar module manufacturer Trina Solar have conducted a series of experiments to assess the impact of ultraviolet-induced degradation (UVID) on the performance of tunnel oxide passivating contact (TOPCon) solar modules and have found that this panel type can offer “metastable resilience” in real-world operation. “Our lab-to-field studies confirm that UVID in TOPCon is a light-recoverable metastable effect with no impact on real-world energy production,” the research’s lead author, Zhiwei Li, told pv magazine. “This is critical for improving investor confidence and bankability, and establishes a clear reliability understanding for the industry.” The researchers conducted UV accelerated aging tests on TOPCon solar cells using a HY-UV-4225 chamber equipped with a metal halide lamp emitting in the 280–400 nm range. During these experiments, the UV intensity was set to 180 W/m², and the module temperature was maintained at 60-65 C, with the samples being placed under short-circuit conditions in a chamber at 50-60 C and exposed to a cumulative irradiation dose of 2 kWh/m² from an 800 W/m² light source spanning 300–1200 nm. The cells were sandwiched between standard module glas
# Current UV tests overestimate TOPCon solar module degradation – pv magazine Global Source: Blog/Web URL: https://www.pv-magazine.com/2025/04/09/current-uv-tests-overestimate-topcon-solar-module-degradation/ Author: Ralph Diermann Date: 2025-04-09 From pv magazine Germany In 2024, researchers at Fraunhofer ISE analyzed the stability of TOPCon, passivated emitter and rear cell (PERC), and heterojunction solar cells under UV irradiation and found that all three cell technologies can suffer significant losses in implied voltage and efficiency. Practical experience has confirmed this finding. With that in mind, other Fraunhofer ISE researchers assessed the validity of standard UV testing methods for TOPCon modules. The result – surprising at first glance – is that conventional UV tests can significantly exaggerate the degradation effect. In these lab tests, experts simulate the natural UV exposure photovoltaic modules face in the field and on rooftops. They increase the irradiation intensity to accelerate aging and estimate long-term performance losses. Testing limits Fraunhofer ISE said modules must be stabilized after testing to produce results that reflect real-world degradation more accurately. Only then can researchers distinguish between UV-sensitive and more stable module types for comparable evaluations. Scientists attributed this to the metastable behavior of commercial TOPCon modules, prompting a reassessment of test procedures and additional field testing. “Many modul
to this degradation mechanism. This indicates that reliability challenges in lightweight module designs are not limited to the solar cell itself, but also extend to module materials and interconnection systems. To improve long-term UV stability, the team proposed a dual-layer encapsulation structure combining a UV-downshifting layer with an additional UV-blocking encapsulant. In this configuration, the upper downshifting layer converts part of the incoming UV radiation into usable visible light, while the secondary UV-filtering layer absorbs residual short-wavelength photons before they reach the SHJ passivation stack. The combined encapsulation structure demonstrated substantially improved stability during accelerated UV aging. The configuration combining UV-downshifting EVA with the stronger UV-blocking encapsulant retained more than 98% of its initial performance after exposure to 120 kWh/m² of UV radiation. According to the researchers, the dual-layer module also maintained significantly higher post-aging efficiency than modules using conventional UV-transmitting encapsulation. The findings were published in the paper titled Mitigation of UV-Induced Degradation in Lightweight SHJ Solar Modules via a UV-Downshifting Encapsulation Strategy in Progress in Photovoltaics: Research and Applications. TaiyangNews has released 5 editions of its Backsheets and Encapsulation Market Survey so far and is currently preparing the 6th edition. Stay tuned for the latest updates on encapsu