Another illustration of the photoelectric effect can be done with a neon lamp. They normally ionize atoms to glow, but only after a certain applied voltage. Tuning the supply voltage just shy of the turn-on point, you can use a light to knock electrons off the electrodes to jump-start the lamp.

https://hackaday.com/2024/08/28/demonstrating-the-photoelectric-effect-using-neon-lamps