NREL Collaborates with University of Colorado Bolder and Demonstrates Reduced Energy Losses in Solar Cells

NREL researchers, in collaboration with the University of Colorado Boulder, have demonstrated that coupling excitons with polaritons—hybrid light-matter states—can reduce energy losses in solar cells and LEDs. By using a two-dimensional perovskite material (PEPI) in an optical cavity, they controlled exciton-exciton annihilation, a key loss mechanism. This approach improved the efficiency of these devices by extending the excited state lifetime. The findings suggest that such strong coupling effects could be applied to other materials, potentially enhancing optoelectronic device performance.

In a recent study published in the Journal of Physical Chemistry Letters, researchers used transient absorption spectroscopy to control a key loss mechanism by adjusting the distance between two mirrors that form a cavity around the 2D perovskite (PEA)₂PbI₄ (PEPI) layer. This material shows promise for future LED applications.

“If we can gain control over exciton/exciton annihilation in the active materials used in an LED or a solar cell, we could reduce the energy losses and therefore increase their efficiency by a significant amount,” said NREL’s chemistry and nanoscience center director Jao van de Lagemaat, who led the study.

“We showed that strong coupling effects can be used to control the excited state dynamics of the PEPI system,” van de Lagemaat added further. “The simplicity of the system suggests that this result should translate into other active materials in LEDs and solar cells and could potentially be engineered into these applications using simple fabrication methods.”