Hebrew University team develops flexible color tunable solar window technology

by Erica Marchand
Paris, France (SPX) Jan 14, 2026
A new solar cell that is designed to work in locations like windows and flexible surfaces where traditional panels cannot has been developed by nanotechnology researchers at the Hebrew University of Jerusalem. The device targets installations on building facades, architectural glass and curved structures where rigid modules are difficult to deploy.

The research, led by Prof. Shlomo Magdassi and Prof. Lioz Etgar from the Hebrew University Institute of Chemistry and the Center for Nanoscience and Nanotechnology, points to new ways of embedding solar technology into windows, building facades and curved surfaces without compromising appearance or performance. The approach focuses on semi transparent, color tunable perovskite solar cells that can blend with their surroundings.

The findings, presented in EES Solar, discuss the fabrication of low temperature processed, flexible, semi transparent and color tunable perovskite solar cells. The researchers can fine tune how much light passes through and what color the cell appears by adjusting the thickness of a transparent electrode layer, without altering the solar material itself.

This control allows the device to reflect selected light wavelengths while continuing to produce electricity from the remaining spectrum. It gives designers greater freedom to choose different visual appearances and levels of transparency, which is important for applications such as solar windows and glass partitions.

At the heart of the design is a pattern of microscopic polymer pillars created using 3D printing. These tiny structures act like carefully shaped openings that regulate light transmission through the device, eliminating the need to change the perovskite absorber layer to achieve semi transparency.

Because the method avoids high temperatures and toxic solvents, it is well suited for more environmentally friendly manufacturing. The low temperature, solvent free process is compatible with flexible substrates and is intended to support scalable production of solar cells for real world use.

"Our goal was to rethink how transparency is achieved in solar cells," said Prof. Magdassi. "By using 3D printed polymer structures made from non toxic, solvent free materials, we can precisely control how light moves through the device in a way that is scalable and practical for real world use."

In laboratory tests, the flexible solar cells reached power conversion efficiencies of up to 9.2 percent, with about 35 percent average visible transparency. They also maintained stable performance after repeated bending and during extended operation, which are key benchmarks for use in architectural and other mechanically flexible environments.

"What is especially exciting is that we can customize both how the device looks and how flexible it is, without sacrificing performance," said Prof. Etgar. "That makes this technology particularly relevant for solar windows and for adding solar functionality to existing buildings."

The team plans to focus next on improving long term durability through protective encapsulation and barrier layers to shield the perovskite material from moisture and oxygen. The goal is to move the technology closer to commercial use by enhancing stability and refining the fabrication process.

Research Report:Semitransparent color tunable perovskite solar cells with 3D pillar structure