Does the Photoelectric Effect cause any kind of decay? From my understanding, the Photoelectric Effect knocks electrons off of some metal using photons.  Since electrons are being thrown out of the metal, does this cause some kind of decay? 
 A: No decay within atoms is where the neutrons or protons change such as beta which is a neutron to proton. Removal of electrons doesn't alter the element or nucleus structure.
A: (I am guessing that you by "decay" mean, "is the material loosing mass slowly". As the other answer suggests, decay is a word reserved for something else in physics.)

"Knocs electrons off" is in this sense quite a simplistic way to describe it. Rather see it like this:


*

*The photoelectric effect is when a photon (light) excites an electron. "Excites" means that it has more energy (a higher energy state), and in this case enough energy to move now (enough energy to reach the socalled conduction band). Moving electrons is current.


Just remember that this material from which the electrons are "ripped off" from - or rather excited in - is a part of a circuit. In an electric circuit the electrons moving away are as part of the current replaced by new electrons right away from further down the circuit. 
Electrons are moving around the circuit at all points at all times if you have a steady current.
