When Were Solar Panels Invented? The 3 Dates That Matter, 1839 to 1954

Solar panels sat on a New York City rooftop in the 1880s.

That’s about 70 years before the silicon cell that today’s roof panels come from even existed.

So when were solar panels invented? Three different years get quoted, and each one is right about something different.

Here’s what happened in each, who did it, and which date to use when someone asks.

Who Invented the First Solar Panel?

Charles Fritts, an American inventor, built the first working solar cells in 1883 by coating the element selenium with a thin layer of gold. His cells turned only about 1% of sunlight into electricity, but they worked without being bathed in a liquid.

That last part was the breakthrough.

Earlier experiments needed metal plates sitting in a liquid, so they stayed in the lab. Fritts made a solid version, and the first solar array, built from his design, went up on a New York City rooftop.

That’s why some historians credit Fritts with the actual invention of the solar cell.

Still, his cells were far too weak to replace a power plant. The idea needed a better material, and that took another 70 years.

Who Discovered the Photovoltaic Effect?

Edmond Becquerel, a French physicist, found the photovoltaic effect in 1839 during photo experiments in his father’s lab. He saw that some materials make an electric current when light hits them.

In other words, light can make electricity directly, with no fuel and no moving parts. That one idea sits under all of modern solar energy, and here’s how solar energy works step by step.

Edmond Becquerel showed it with 2 plates, one platinum and one gold, sitting in an acid, neutral or alkaline solution under sunlight. That was the very first electrochemical cell, and it was far too weak for anything outside the lab.

The next clues came from selenium.

In 1873, Willoughby Smith found that selenium reacts strongly to light. Then in 1876, William Grylls Adams and Richard Evans Day showed it makes electricity in sunlight.

When Did Bell Labs Invent the Silicon Solar Cell?

Bell Labs invented the first practical silicon solar cell in 1954, built by Daryl Chapin, Calvin Fuller and Gerald Pearson. Published histories put its efficiency at either 4% or 6%, which is 4 to 6 times better than the 1883 selenium cell.

Why do so many people call this the real invention?

Because it was the first solar technology that could power an electrical gadget for several hours a day. Selenium never got there.

Silicon also stuck. Solar cells as we know them today are made with silicon, not selenium, so every rooftop panel traces back to that 1954 design.

You can see what else goes into one in this rundown of solar cell materials.

When Were Solar Panels First Used in Space?

Solar panels were first used in space in 1958, when the Vanguard I satellite ran its radios on a tiny 1-watt solar panel. Some of the first real jobs for solar technology were in orbit, not on Earth.

The space race kept that going.

Vanguard II, Explorer III and Sputnik-3 all flew with solar power on board. By 1966, the first NASA Orbiting Astronomical Observatory ran on a 1-kilowatt array.

That’s a 1,000-fold jump in power in 8 years, and it shows where solar cell technology grew up.

When Were Solar Panels First Used on Houses?

Solar One, built in 1973 by the University of Delaware, was the first solar building, running on a mix of solar heat and solar electricity. It was also the first building with solar built into the roof itself, instead of panels mounted on top.

That design is called building-integrated photovoltaics, or BIPV. Tesla later used the same idea for its solar roof.

The timing wasn’t random.

The 1970s oil crisis pushed governments to offer incentives for solar, and residential solar first showed up then. But it stayed rare until prices fell.

How Efficient Were the First Solar Panels Compared to Today’s?

The first solar cells, built by Fritts in 1883, turned about 1% of sunlight into electricity. Some panels sold in the 2020s reach 25%, a 25-fold jump in about 140 years.

Here’s how the record climbed:

1. 1883: Fritts gets selenium to about 1%.
2. 1954: Bell Labs gets silicon to 4% to 6%.
3. 1957 to 1960: Hoffman Electronics pushes the record from 8% to 14%.
4. 1985: Silicon cells hit 20%.
5. 1999: The National Renewable Energy Laboratory and Spectrolab hit 33.3%.
6. 2016: Researchers reach 34.5%.

Note: Those records are single cells, not whole panels. A rooftop panel lands lower, and the limits of panel efficiency explain why.

When Did Solar Panels Become Affordable for Homeowners?

Solar panels became affordable for homeowners in the 1990s and 2000s, when better efficiency and lower production costs made them practical. Prices kept falling, from about $300 per watt in 1956 to as little as $0.50 per watt by 2021.

In fact, panel prices have dropped by at least 10% every single year since 1980.

Here’s what that looks like:

In 1975, a watt of solar still cost just over $100. So a small 1-kilowatt system would have cost over $100,000 in panels alone.

At $0.50 a watt, the same panels cost about $500. That’s huge.

Residential solar demand followed the price, and the U.S. passed 1 million solar installations in early 2016. Here’s what a modern 10kW solar system costs, and how cheap panels reshaped the solar energy economy.

How Long Have Solar Panels Been Around?

Solar panels have been around for 143 years as of 2026, counting from the first Fritts selenium cell in 1883. Count from the 1954 silicon cell and modern panels are 72 years old.

The science is older still. Becquerel’s discovery in 1839 was 187 years ago.

So the honest answer depends on what you count, and these fun facts about solar energy add more numbers like it.

Which Invention Date Should You Use?

The best invention date to quote for solar panels is 1954 for modern panels, or 1883 for the very first solar cell.

Save 1839 for the discovery behind both.

Curious how that 1954 idea became a roof panel? See how solar panels are made today.