Light emitting diodes as we know serve as light sources or photon generators. Photons are generated on the depletion region where electrons and holes recombine. The PN junction of LEDs also generate electrons and holes when exposed to light. As demonstrated on this experiment, a green LED is connected to a red LED in parallel connection. The green LED is exposed to the beam of a green laser pointer and generates a small current that is enough to turn on the red LED. This experiment demonstrate that LEDs can also function as a solar cell though less efficient compared to commercial ones.