Researchers from ARC Center for Excellence and Monash University have created semi-transparent solar cells that can be incorporated into window glass, allowing windows to power buildings. These transparent solar cells are the next-generation of perovskite solar cells that can generate electricity and allow light to pass.

The team used organic semiconductors that can be made into polymers and replace a common solar cell component called Spiro-OMeTAD. This component has low stability because it developed an unhelpful, watery coating. The new semiconductors overcome this issue.

A semi-transparent perovskite solar cell with contrasting levels of light transparency. Source: Dr Jae Choul Yu

The new cells transform windows into active power generators. Two square meters of the solar window will generate as much electricity as standard rooftop solar panels. For rooftop solar panels, the conversion efficiency is between 15-20%. The new semi-transparent cells have a conversion efficiency of 17% while transmitting more than ten percent of incoming light.

Solar windows are great for building owners and residents, but they bring new challenges and opportunities for architects, builders, engineers and planners. There is a trade-off with the windows. The more transparent a solar cell is, the less power it generates, and the less transparent the solar cell is the more power it generates.

The team says that its first application should be in multi-story buildings. The large windows in high rise buildings are expensive to make, but adding semi-transparent solar cells is a marginal cost. It turns passive windows into electricity producing windows.

The team is looking for ways to develop large scale glass manufacturing processes so the production of the semiconductors can be easily transferred to industries. They are also investigating how it could be built into commercial products by teaming up with Viridian Glass.

The next step is for the team to create a tandem device with the perovskite solar cells on the bottom layer and organic solar cells as the top layer. They aim to have the product ready for production within the next 10 years.

A paper on this technology was published in Nano Energy.