The suns energy emission varies by wavelength. You are right that the sun gives off the most amount of its energy as visible light in the green region of the spectrum (483-520 nm). All plants on earth, even the single-celled plants that grow in the ocean, contain chlorophyll-a as their main light-absorbing pigment. Plants have other pigments for absorbing light as well, including chlorophyll-b, chlorophyll-c and pigments known as carotenoids, but chlorophyll-a remains the main light-absorbing pigment. Chlorophyll-a absorbs light throughout the visible spectrum, but mostly in the blue and red regions and very little in the green region. In fact, of all the many pigments that plants use to absorb light, none of them absorb much green light.