Light knocks electrons out of metal — but only if its wavelength is short enough, and no amount of brightness will substitute. That refusal is what made the quantum real.
Photoemission in three steps — excite, travel, escape. Three views: real space, energy, and momentum. The electron is not bound to any one atom to start with, so what it has to pay to get out is the work function, not the atom’s ionisation energy. And no voltage is involved — a field would make a current, which is a different thing entirely. Fire a photon and step through it.