07 September, 2025
A naturally occurring polymer commonly used as a medical anticoagulant can improve the stability, flexibility and efficiency of next-generation perovskite solar cells, KAUST researchers have discovered. The polymer acts as a molecular bridge between two crucial layers within the solar cell, easing the flow of electrical charge and helping to make the devices more robust.
Perovskites are a family of light-harvesting semiconductors based on abundant, inexpensive materials such as lead and iodine. While most commercial solar cells rely on relatively thick slabs of crystalline silicon, perovskite solar cells have a much thinner light-absorbing layer, enabling lightweight and flexible devices. The efficiency of perovskite solar cells has soared over the past 15 years, with the best cells converting 27 percent of the light that falls on them into electricity, similar to the most efficient silicon cells.
However, perovskite cells also tend to degrade much more rapidly than silicon cells, partly due to problems at the interfaces between layers inside the perovskite cells, which can reduce efficiency and make the cells more fragile.
When light hits a solar cell, it frees electrons in the absorbing layer, which move into an adjacent electron transport layer, made of materials such as tin oxide, and onwards to an electrode. Weak binding between these layers can reduce the mechanical strength of the device, while defects at interfaces can trigger perovskite decomposition and significantly reduce the cell’s efficiency.
Other researchers have previously used small molecules to address these interface problems. “But small molecules usually cannot provide the structural integrity and high mechanical stability and flexibility that polymers like heparin sodium can offer,” explains Omar F. Mohammed, who led the research at KAUST.
Read more at KAUST Discovery.