When plants use sunlight to make food, the energy of sunlight is use for photosynthetic efficiency. This refers to the fraction or fractions of light energy that is eventually converted into chemical energy during photosynthesis in plants. Where chemical reactions produce sugars, cellulose, and other nutrients that the plant can use to thrive and survive in its environment.
However, plants do not actually absorb all incoming sunlight due to reflection and respiration properties in photosynthesis. They do not convert all harvested energy, instead they have the capacity to store this in their cells and harvest them when the need arises.