Ultra-thin Transparent Perovskite Solar Cells Open New Urban Energy Potential

Scientists from Nanyang Technological University Singapore have developed an ultra-thin, semi-transparent perovskite solar cell that turns everyday glass surfaces into power-generating units. The innovative technology can be integrated into vehicle windows, smart eyewear and building facades, turning futuristic energy-harvesting scenarios into practical reality. Relevant research findings are published in ACS Energy Letters.

The new photovoltaic device features an extremely slim structure. Its thickness measures just one ten-thousandth of a human hair and one-fiftieth of conventional perovskite solar cells. Despite its ultra-light form factor, the cell achieves competitive power conversion efficiency, ranking among the top tier of current ultra-thin perovskite photovoltaic technologies.

Buildings account for around 40 per cent of global energy consumption, making power-generating building surfaces a viable solution for urban energy optimisation. The novel perovskite cell can be fabricated at low temperatures, with adjustable light absorption spectra that balance optical transparency and power generation performance. Its compatibility with large-area manufacturing effectively cuts carbon emissions throughout the production process and lowers overall carbon footprints.

Distinct from traditional silicon-based solar cells, the device delivers stable performance under diffused and indirect sunlight. The operational advantage makes it highly suitable for dense urban areas where tall buildings block direct solar radiation. Large-scale deployment of the technology can transform building glass curtain walls into functional power-generating facades. Industry estimates show that such architectural retrofits can yield hundreds of megawatt-hours of electricity annually, matching the yearly power consumption of approximately 100 four-room residential units.

The research team adopts a thermal evaporation vacuum deposition technique for production. Raw materials are heated and evaporated in a vacuum environment before being deposited into uniform ultra-thin perovskite light-absorbing films. The solvent-free manufacturing process eliminates toxic solvent usage, reduces structural defects in photovoltaic materials, and further improves overall photoelectric conversion efficiency.

Experimental data reveals clear performance differences across varied cell thicknesses. Opaque devices with perovskite layers of 10 nanometres, 30 nanometres and 60 nanometres achieve conversion efficiencies of around 7 per cent, 11 per cent and 12 per cent respectively. Semi-transparent cells with a 60-nanometre layer maintain a 7.6 per cent conversion rate while allowing 41 per cent of visible light to pass through, striking an optimal balance between indoor daylighting and clean power generation.

The cell’s neutral colour and semi-transparent properties support seamless integration into modern infrastructure and wearable devices. Embedding the ultra-thin solar units into architectural windows, glass curtain walls and smart electronic wearables enables on-site power generation without altering original exterior designs. The breakthrough expands renewable energy utilisation scenarios and provides a flexible, low-carbon solution for future urban energy systems and portable electronic devices.