If you double the GHG molecules (double the concentration) each molecule will be having it easy for it is working half as hard absorbing photons. (wattsupwiththat.com)
These panels are made up of photovoltaic cells, which absorb the photons from sunlight and energize electrons in the cell's material, creating electricity. (scientificamerican.com)
By absorbing a photon of light, photosensitive molecules can reposition chemical bonds and thus create a «kink» in the polymer chain. (scientificamerican.com)