Singapore Unveils Invisible Solar Cells for Windows

Every window in your city could soon be quietly generating electricity while you look right through it.

Researchers at Nanyang Technological University in Singapore developed solar cells so thin they're practically invisible. At just 10 nanometers thick, these cells are 50 times thinner than conventional solar panels and can be installed directly onto windows without blocking your view.

The breakthrough solves a massive problem for cities trying to go solar. Skyscrapers don't have enough roof space for traditional panels, and their walls are covered in glass. Adding heavy, opaque solar panels would completely change how buildings look and function.

These new perovskite solar cells weigh almost nothing and stay color-neutral, meaning your windows won't turn weird shades of blue or orange. The team can adjust transparency during manufacturing by controlling the thickness of the material layer by layer.

The semi-transparent version lets 41% of visible light pass through while converting 7.6% of sunlight into electricity. The opaque versions reached up to 12% efficiency. That's lower than the 20% efficiency of modern rooftop panels, but the comparison misses the point.

These cells work in conditions where traditional panels struggle. Unlike silicon solar cells that need direct sunlight, perovskite devices generate power even in shade or cloudy weather. That matters enormously in dense cities where buildings cast shadows across each other all day long.

Professor Annalisa Bruno's team tested the cells at multiple thicknesses. Even the thinnest 10-nanometer version achieved 7% efficiency, proving you don't need bulk to capture energy.

The Ripple Effect

Imagine entire glass skyscrapers becoming power plants. Office towers consume gigawatt-hours of electricity annually, and their walls offer vastly more surface area than their roofs. Adding transparent solar to existing windows, car sunroofs, greenhouses, and even eyeglasses could create millions of new energy-generating surfaces.

The technology also works better in real-world conditions than efficiency numbers suggest. Perovskite cells continue producing power under indirect lighting, meaning north-facing walls and shaded surfaces could contribute too.

Cities desperately need renewable energy but lack space for massive solar farms. This technology uses infrastructure that already exists. The glass is already there, dominating modern architecture. Now it can work double duty.

The researchers published their findings in ACS Energy Letters in May 2026. Manufacturing these ultrathin cells costs less than conventional panels because perovskite materials are cheaper and require less processing.

Windows that power buildings could transform urban energy independence from an impossible dream into architectural reality.