1876 for selenium based solar cells. https://en.wikipedia.org/wiki/Selenium#Solar_cells https://en.wikipedia.org/wiki/Selenium#Solar_cells Silicon solar cells

1876 for selenium based solar cells. https://en.wikipedia.org/wiki/Selenium#Solar_cells https://en.wikipedia.org/wiki/Selenium#Solar_cells Silicon solar cells are/were massively more effective, and came to light just before their popularization in the space race.