The time period ending in 2025 will be an important time period for the solar photovoltaic sector to consider. In addition to seeing TOPCon and n-type technologies, as well as the other market leaders, this period will also highlight many unresolved issues regarding the long-term performance and reliability of both technologies. The rapid transition from the older p-type PERC technology to the newer products has caused many unexpected quality issues to arise, which have resulted in the need for all manufacturers to take extra care in producing these products, as well as for underpinning manufacturing standards across the industry to be updated.

Accelerated Rates of Failure and Most Common Problems

The most significant indicators of these issues are provided by industry standards. The most recent Kiwa PVEL 2025 Module Reliability Scorecard indicates an increase in module reliability test failure rates from 66% in 2024 to 83% this year and an increase in test failures from 68% in 2022 to 67% in 2023, and 66% in 2024. While many previously identified issues remain unsolved, there are also numerous new problems that are being created by the increasing number of failed tests. All these factors present pressing opportunities for solutions for the module manufacturers.

Multiple recurring failure modes have been identified by Subject Matter Experts (SME) and Industry Leaders at events like the PV ModuleTech Europe conference. Ultraviolet-Induced Degradation (UVID), glass breakage, and delamination are the most frequently cited issues. Delamination is the separation of the layers of the module and is currently symptomatic of more significant impacts of supply chain pressures on manufacturers. It has been credited to the use of more cost-effective materials that have been manufactured with thinner encapsulants, a reduction in the quality of materials being sourced, or the acceleration of the lamination process for increased production throughput.

TOPCon Technology Under the Microscope

While n-type technology broadly has shown advantages like resistance to Light- and Elevated Temperature-Induced Degradation (LeTID), TOPCon modules have been at the center of specific reliability investigations. A comprehensive study by researchers from Fraunhofer ISE and other German institutions, which evaluated 20 commercial TOPCon modules, identified “significant reliability issues that remain unresolved.”

The research confirmed that while TOPCon cells excel in certain areas, they exhibit concerning vulnerability to Potential-Induced Degradation (PID), corrosion, and, most notably, UVID. The study concluded that degradation from UV exposure and moisture ingress was “critical.” A complicating factor is the inherent metastability of TOPCon cells; they can degrade when stored in dark conditions but partially recover when re-exposed to light. This characteristic makes accurate, real-world degradation assessment challenging, as noted by Steven Xuereb of Kiwa PI Berlin, who explained that standard lab tests can sometimes overstate permanent performance loss.

The UVID issue has gained significant attention. Research from the National Renewable Energy Laboratory (NREL) on underperforming field systems detected “severe” levels of UVID, leading to calls for enhanced global testing standards. Concurrently, scientists at the University of New South Wales emphasized that more precise awareness of UV light types used in testing could lead to faster and more accurate predictions of long-term field performance.

The Cost-Quality Conundrum

Industry analysts directly link the rise in quality issues to severe financial pressures within the solar manufacturing sector. With module prices hitting historic lows, major manufacturers reported substantial financial losses in the first half of 2025. To stem these losses, companies have aggressively pursued cost reduction across their bill of materials (BOM) and production processes.

Tristan Erion-Lorico of Kiwa PVEL observed that the drive for “eight-cent or nine-cent modules” has led manufacturers to remove materials and accelerate processes, inevitably introducing reliability risks. This sentiment suggests that the root cause may not be an inherent flaw in TOPCon technology itself, but rather the aggressive cost-optimization in its manufacturing during an industry downturn. This has led to a widening gap between the promise of high-efficiency n-type technology and the field reliability of some mass-produced modules.

Industry Response and Path Forward

The industry has begun mobilizing on multiple fronts to combat these challenges. Numerous prominent manufacturers have begun taking action to address vulnerabilities caused by UVID, by developing more sophisticated passivation and encapsulants for cells. In addition, organizations such as Kiwa PI Berlin have started to encourage manufacturers to conduct more thorough due diligence on quality assurance and the auditing of their supply chains to ensure that they comply with all applicable standards, not just pricing.

The many themes emerging in 2025 illustrate an essential transformation within the solar industry. The drive for lower $/Watt and higher laboratory efficiencies is now gradually giving way to equal emphasis on durability, bankability, and total energy yield over the entire life of an installation. As such, there is a growing need for updated protocols that reflect the challenges of real-world conditions and provide adequate support for the emerging technologies Apple and FIRST have offered, particularly TOPCon.

In conclusion, 2025 will be remembered as the year the photovoltaic industry confronted the growing pains of its own technological success. The dominance of TOPCon and n-type is undeniable, but their long-term legacy will be determined by how effectively manufacturers, researchers, and standards bodies collaborate to translate laboratory innovation into field-proven, reliable products that deliver on their 25-year promises. The solutions developed in response to this year’s challenges will likely define the quality and sustainability of the global solar fleet for decades to come.