A new coating strengthened thin glass by up to seven times in laboratory tests, potentially reducing solar panel weight and glass consumption through the use of thinner glass.
Solar panels could become lighter if their protective glass can be made thinner without compromising strength. German company EXXOSQEL is developing a coating that reinforces microscopic cracks in glass, potentially reducing the amount of glass used in photovoltaic modules by up to 40 per cent and total module weight by about 30 per cent.
The technology was developed by EXXERGY and is being industrialised by its spin-off EXXOSQEL in collaboration with the Fraunhofer Institute for Silicate Research ISC in Würzburg, Germany. Fraunhofer’s Center for Silicon Photovoltaics CSP in Halle is involved in testing the technology on photovoltaic modules. The companies reported the results on 19 October 2026 through the research news service Informationsdienst Wissenschaft.
Glass contributes significantly to a solar module’s weight. Conventional modules commonly use glass around 3.2mm thick, which can undergo thermal tempering to improve its strength. However, conventional thermal tempering becomes more challenging with thinner glass. Chemical strengthening offers another approach, but its processing requirements can complicate large-scale manufacturing.
The new coating addresses a different problem: microscopic cracks on the glass surface that can grow under mechanical stress and eventually cause the material to fracture. The coating forms a three-dimensional composite whose matrix creates covalent bridges within these microcracks at the molecular level. According to Thomas Sauer, managing director of EXXOSQEL, this increases the energy required for cracks to propagate. The companies have not disclosed the complete chemical formulation.
In laboratory tests using untempered glass as the reference, the coating increased measured strength by up to four times for 2mm-thick samples and up to seven times for 1mm-thick samples. These results suggest that thinner glass could offer improved mechanical performance without relying on conventional thermal tempering. However, the reported improvements apply to laboratory samples and should not be interpreted as equivalent strength gains across finished commercial modules.
The companies estimate that the technology could reduce glass consumption by up to 40 per cent, potentially lowering total photovoltaic module weight by approximately 30 per cent. Their example describes a module weighing 16kg/m² becoming approximately 11kg/m². For a module covering 2m², that would represent a reduction of roughly 10kg. These are projected outcomes based on the proposed material reduction, rather than independently verified savings from commercial installations.
Lower module weight could reduce handling and transportation requirements and potentially allow lighter mounting structures. This may be useful for rooftop installations where structural loading is an important consideration. However, reducing panel weight alone does not establish that a roof can support a solar installation; structural assessments must also account for mounting loads, wind forces and other site-specific conditions.
The technology is not yet commercially established. EXXOSQEL says its coating development for flat glass is progressing towards Technology Readiness Level 6, which involves validation in a relevant environment. The team has produced initial standard-size prototypes under practical conditions, with load testing under way. Reaching Level 7 would require demonstration under operational conditions. The reported performance figures currently come from the companies’ announcement rather than a published peer-reviewed study.
For India, lighter photovoltaic modules could be relevant to the expansion of rooftop solar under the PM Surya Ghar Muft Bijli Yojana, which targets installations in one crore households. Reduced module weight could offer flexibility in some installations, although the actual benefits would depend on module design, mounting-system requirements and site conditions. India also has domestic solar-glass manufacturers, making material efficiency relevant to the wider photovoltaic supply chain. Before adoption, the coating would need to demonstrate durability under India’s varied climatic conditions, including heat, humidity, thermal cycling and exposure to severe weather.
The next step is to validate the coating on larger modules and under operating conditions. If its strength improvements and manufacturing compatibility hold up during testing, the technology could provide a route to lighter solar panels while reducing glass consumption.
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