You don't have to try hard. Just use it as a photodiode and it magically works. However, if it's inside a plastic case that blocks light, it doesn't.
Due to some law about entropy, efficient processes are necessarily reversible. That's why electric motors - some of the most efficient machines ever invented - are also generators.
> However, if it's inside a plastic case that blocks light, it doesn't.
You want an ordinary diode to allow current to flow easily when it senses light? Simple: shine a powerful laser at the plastic-encased diode and it will melt the plastic and liquify the metal, fusing it together and allowing current to flow again. See? You just needed to try harder.
Due to some law about entropy, efficient processes are necessarily reversible. That's why electric motors - some of the most efficient machines ever invented - are also generators.