It's important to clarify the distinction between dark energy and dark matter. Dark energy is a hypothetical form of energy that is believed to be responsible for the observed accelerated expansion of the universe. On the other hand, dark matter is a form of matter that does not interact with light or other electromagnetic radiation and is inferred to exist based on its gravitational effects on visible matter.
Dark matter and dark energy have different roles in the expansion of the universe. Dark matter, despite not directly interacting with light, still exerts gravitational influence. It contributes to the overall mass density of the universe, which affects the expansion rate through its gravitational pull.
The current understanding is that dark matter's contribution to the overall matter density in the universe causes it to slow down the expansion. This is because gravity acts as an attractive force, and the presence of matter, including dark matter, tends to slow down the expansion driven by dark energy.
However, it's worth noting that the detailed interactions between dark matter, dark energy, and the expansion of the universe are still active areas of research. Our understanding of these phenomena continues to evolve, and scientists are working to refine and develop theories that can explain the observed behavior of the universe.