Science & Technology (Commonwealth Union) – Solar energy has been a key focus for energy particularly in areas with high sunlight.
The possibility of powering a building via its windows may move closer to reality thanks to a newly developed ultrathin transparent solar cell created by scientists at Nanyang Technological University.
Under the leadership of Professor Annalisa Bruno, the research team designed perovskite solar cells that are roughly 10,000 times thinner than a human hair and about 50 times slimmer than standard perovskite solar cells.
Even with their extremely thin structure, the cells delivered some of the strongest power conversion efficiencies yet recorded for ultrathin perovskite solar technology.
Recently published in the scientific journal ACS Energy Letters, the study suggests a future where solar cells could be seamlessly built into buildings, vehicles, and wearable technology without noticeably altering their look.
Since the new solar cells are semi-transparent and maintain a neutral colour, they could be integrated into windows and building façades without greatly altering a structure’s appearance.
Professor Bruno, from the NTU, School of Physical and Mathematical Sciences and School of Materials Science and Engineering indicated that the built environment is responsible for around 40 per cent of global energy use, making technologies that can effortlessly transform building surfaces into sources of power increasingly important.
Professor Bruno who carried out the experiments at the Energy Research Institute at NTU where she serves as Cluster Director for Renewables & Low-Carbon Solutions and Energy Storage indicated that their perovskite solar cells have several key benefits because they can be produced through simple manufacturing methods at comparatively low temperatures. She further pointed out that they can also be engineered to absorb selected wavelengths of light while staying transparent, and may eventually be produced on a large scale, helping to lower their carbon footprint.
Unlike traditional silicon solar cells, these perovskite-based devices can produce electricity even in indirect sunlight and low-light conditions. This makes them especially suitable for Singapore’s dense urban landscape, where tall buildings and frequent cloud cover often reduce direct exposure to sunlight.
If the technology were expanded while maintaining similar efficiency, large glass façades could potentially become energy-generating surfaces.
Early estimates indicate that installing the technology across a major glass-covered building, such as an office tower in Raffles Place or Marina Bay, could theoretically produce several hundred megawatt-hours of electricity each year.
Based on the amount of usable glass and the orientation of the building, this could match the yearly electricity usage of around 100 four-room HDB flats.
Perovskite solar cells consist of multiple layers, including a semiconductor layer that captures sunlight and transforms it into electrical energy.
To produce the ultrathin cells, the NTU research team employed an industry-friendly technique called thermal evaporation. During this process, raw materials are heated inside a vacuum chamber until they vaporise. The resulting vapour then settles onto a surface, creating a thin film.
This approach enables the formation of extremely thin and even perovskite coatings across large surfaces. It also eliminates the need for toxic solvents and helps minimise defects within the solar cells, enhancing their efficiency in converting sunlight into electricity.
By fine-tuning the technique, the scientists were able to regulate the thickness of the perovskite layer and manufacture both opaque and semi-transparent solar cell devices.
The first author of the paper, Dr Luke White, a former PhD student at the Energy Research Institute for the NTU, School of Physical and Mathematical Sciences, and the School of Materials Science and Engineering, says “By precisely controlling thermal evaporation, we are able to adjust the transparency of the solar cells. This opens up new possibilities for sustainable architecture, such as tinted windows that generate electricity.”
