Daryl Muscott Chapin[1] (21 July 1906 – 19 January 1995) was an American physicist, best known for co-inventing solar cells in 1954 during his work at Bell Labs alongside Calvin S. Fuller and Gerald Pearson.

They created a p–n junction by dipping a gallium-doped silicon piece in lithium at around 500 °C before exposing it to sunlight, hence discovering its ability to generate photocurrents.

Pearson informed Chapin of this discovery, prompting him to switch materials and after a year the functional solar cell was demonstrated on 25 April 1954.

It initially failed to gain major commercialization due to its still-prohibitive costs and found only niche use in small electronic devices such as the transistor radio.

[9] For the discovery, Chapin was awarded an honorary doctorate by his alma mater, Willamette, and the John Scott Medal from Philadelphia, both in 1956.