Photon absorption is the process by which a material takes in light energy from a photon, which is a particle of light. When a photon strikes an atom or molecule, its energy can be transferred to the electrons, causing them to move to a higher energy level. This process is essential in various applications, including photosynthesis in plants and the functioning of solar panels. The efficiency of photon absorption depends on the material's properties, such as its band gap and structure. Different materials absorb different wavelengths of light, which is why colored filters can change the appearance of light. Understanding photon absorption is crucial in fields like optics and photovoltaics.