Who Invented Solar Panels?

No single person invented the solar panel. It took a string of discoveries over more than a century, from a teenage French physicist in 1839 to a team at Bell Labs in 1954. Here’s how it came together.

1839: Edmond Becquerel discovers the photovoltaic effect

At age 19, working in his father’s lab in Paris, Edmond Becquerel noticed that shining light on certain materials in a solution produced a small electric current. This is the photovoltaic effect, the basic principle behind every solar cell today.

1860s and 1870s: Augustin Mouchot’s solar engines

French inventor Augustin Mouchot built machines that used mirrors to concentrate sunlight, boil water and run small steam engines, and he later used solar heat to make ice. His work was solar thermal, not photovoltaic, but it showed that sunlight could do practical work.

1873 and 1876: Selenium reacts to light

English engineer Willoughby Smith discovered in 1873 that selenium conducts electricity better in light than in darkness. In 1876, William Grylls Adams and his student Richard Evans Day showed that light alone could make selenium produce an electric current, with no heat or moving parts involved.

1883: Charles Fritts builds the first selenium solar cell

American inventor Charles Fritts coated selenium with a very thin layer of gold and described the result in a paper published in December 1883. It’s generally considered the first working solar cell. It converted about 1% of sunlight, or less, into electricity. Fritts is also commonly credited with installing an array of these cells on a New York City rooftop around 1884, though that detail comes from later retellings rather than well-documented records.

1880s to 1910s: Early solar patents

Several American inventors patented devices for turning sunlight into electricity during this period:

• Edward Weston received US Patents 389,124 and 389,125 on September 4, 1888.
• Melvin Severy received US Patents 527,377 and 527,379 in 1894.
• Harry Reagan received US Patent 588,177 in 1897 for applying solar heat to thermo-batteries.
• William Coblentz received US Patent 1,077,219 in 1913 for a thermal generator.

These were thermoelectric devices. They used sunlight to heat junctions of different metals, which produced a current, rather than using the photovoltaic effect directly. They were important experiments but not the ancestors of modern panels.

Around the same time, in 1888, Russian physicist Aleksandr Stoletov built one of the first cells based on the photoelectric effect and studied how it worked. Albert Einstein’s 1905 explanation of the photoelectric effect, which later earned him the Nobel Prize, helped scientists understand why these materials responded to light.

1954: Bell Labs creates the silicon solar cell

On April 25, 1954, Bell Laboratories announced a silicon solar cell developed by Daryl Chapin, Calvin Fuller and Gerald Pearson. At about 6% efficiency, it was the first solar cell practical enough to power real equipment. Modern solar panels are direct descendants of this design, and the three inventors were later inducted into the National Inventors Hall of Fame.

1958: Solar power goes to space

Vanguard 1, launched in March 1958, was the first satellite powered by solar cells. At the time, solar cells were far too expensive for most uses on Earth, so space was where the technology matured.

1970s: The energy crisis

Oil shortages in the 1970s pushed governments to take solar seriously. In 1973, the University of Delaware opened Solar One, one of the first homes to combine solar electricity and solar heat. In 1974, Congress passed the Solar Energy Research, Development and Demonstration Act, which led to the Solar Energy Research Institute. That lab later became the National Renewable Energy Laboratory and was renamed the National Laboratory of the Rockies in 2025.

Today

Solar panels are now one of the cheapest sources of new electricity in much of the world. Home panels are about 21% to 24% efficient, up from roughly 6% for the first Bell Labs cell. In 2026, LONGi reported a record 28.29% efficient silicon cell and a 35.5% efficient perovskite-silicon tandem cell in the lab. For how these modern panels work, see how solar energy works and the most efficient solar panels.

Sources

• American Journal of Science: Fritts, “On a New Form of Selenium Cell” (1883)
• Nature: Willoughby Smith on selenium (1873)
• Royal Society: Adams and Day, “The Action of Light on Selenium”
• Google Patents: US 389,124 (Weston)
• American Physical Society: Bell Labs demonstrates the first practical silicon solar cell
• University of Delaware: Karl Böer and Solar One
• US Department of Energy: NREL renamed National Lab of the Rockies