Is solar radiation at earth's surface sufficient to eject electrons from aluminum? Is solar radiation at earth's surface sufficient to eject electrons from aluminum?
 A: It looks like you are referring to the photoelectric effect. There is a minimal energy required to eject an electron from a surface through the photoelectric effect. In the case of aluminum, this energy is about 4.1 eV, which corresponds to a wavelength of about 302 nm. That is, any photon having a wavelength of more than 302 nm will not have enough energy to eject the electron from aluminum.
Even in outer space, there is only a bit (in percentage) of energy in sunlight in that region of the spectrum. In addition, the atmosphere absorbs a lot at these wavelengths. Notably, Ozone absorption is strong at such wavelengths. However, there is still some light around these wavelengths that reaches the ground. In fact, this is right in band of wavelengths required for Vitamin D production in the skin. Therefore, in theory, solar radiation can eject electrons from aluminum. However, the resulting current would most likely be very small, and will depend on the angle of the sun with the horizon (which can lead to larger absorption by Ozone).
