Quick answer
Photovoltaic Cell A photovoltaic cell, or solar cell, is a thin piece of semiconductor, usually silicon, that produces direct-current electricity when light falls on it.
One cell makes only about 1 to 2 watts, so manufacturers wire dozens of them together and seal them behind glass to make a solar panel. The cell is where the energy conversion actually happens; everything else in a panel protects it and carries its current.
Quick facts
The key facts about photovoltaic cell, with sources:
- Output per cell
- About 1–2 W 1
- Size
- About 0.5 to 4 inches across 1
- Thickness
- Often thinner than four human hairs 2
- Made of
- Semiconductor material, sandwiched between glass and/or plastic 2
- Most common type
- Monocrystalline silicon, 96% of global shipments in 2022 3
- Factory module efficiency
- About 20%–22% for silicon; lab cells above 27% 3
- Produces
- Direct current (DC)
- Where you see it
- The "Cell" row of a panel data sheet, e.g. "6 × 16 monocrystalline half cells" 9
Key takeaways
- A solar cell is the part that turns light into electricity. The rest of the panel protects it.
- One cell is small: about 1 to 2 watts, so a panel wires dozens together.
- Almost all home panels use silicon cells. Half-cut cells are now common.
- One shaded or cracked cell can pull down a whole group of cells.
- You cannot repair one cell. A failed cell means a panel swap by your installer.
What is inside a solar cell
A cell is two layers of semiconductor. A semiconductor is a material that carries current only under certain conditions, such as when light hits it. One layer is treated to hold extra electrons. The other has room for them. The boundary between them sets up an electric field.
When light frees an electron near that boundary, the field pushes it toward the front surface. Thin metal lines printed on the cell collect it. These are the silver "fingers" you can see on many panels.
The EIA compares the result to a battery. A voltage forms between the front and back of the cell, and current flows once a circuit connects them. Unlike a battery, the cell stores nothing. It makes power only while light reaches it.
How a cell’s power reaches your home
What limits how much a cell makes
Not all light becomes power. Some reflects off the surface. Some passes through. Some is too weak or too strong in color to free an electron cleanly, and turns into heat. This is why a silicon cell turns only about a fifth of sunlight into electricity.
Heat makes it worse. A hot cell makes less voltage than a cool one, so output dips on hot days. Area also matters. A bigger cell catches more light and makes more current.
The DOE says factory silicon modules reach 20%–22% in the real world. The best silicon lab cells pass 27%.
Cell types you will see named on a panel
| Cell type | What it means | Glossary |
|---|---|---|
| Monocrystalline silicon | Cut from a single silicon crystal; uniform dark color. The common choice for homes. | Monocrystalline |
| Polycrystalline silicon | Cast from many crystals; bluish, speckled look. Less common in new home systems. | Polycrystalline |
| Thin film | A very thin semiconductor layer laid on glass rather than a wafer. Cadmium telluride is most of the non-silicon market 3. | Thin film |
| PERC | A silicon cell with an extra back layer that bounces light back in. Led the market from about 2018 3. | PERC |
| N-type (TOPCon, HJT) | Newer silicon designs now replacing PERC 3. | TOPCon, HJT |
| IBC | All metal contacts on the back, so the front is clean. Made in smaller numbers 3. | IBC |
| Half-cut cell | A standard cell sliced in two, so each half carries half the current. This cuts resistive loss and lets half the panel keep working if the other half is shaded. | — |
Example: what the cells add up to on one data sheet
The Qcells Q.TRON BLK S-G3R.12+ 435 W panel lists its cell layout and electrical figures at standard test conditions. Reading them together shows how cells build a panel.
| Data-sheet line | Value | What it tells you |
|---|---|---|
| Cell | 6 × 16 monocrystalline half cells (96) 9 | Half cells, so each is wired to carry half the current of a full cell |
| Voltage at maximum power | 29.42 V 9 | The cells’ voltages add up because they are wired in series |
| Current at maximum power | 14.79 A 9 | Set by the cell area and the light |
| Power | 29.42 V × 14.79 A ≈ 435 W | Matches the panel’s 435 W rating |
| Per cell | 435 W ÷ 96 ≈ 4.5 W | Higher than the EIA’s 1–2 W rule of thumb because these are large modern cells |
Two panels with the same wattage can use different cell counts. Cell count matters to you only through the panel’s size, voltage and wattage, which your installer matches to the inverter.
Where solar cells are used
Solar cells first went to work in the 1950s. Bell Telephone built the first practical one in 1954, and satellites carried them from the late 1950s. Today they power calculators, road signs, rooftops and huge solar farms.
Different jobs use different cells. Homes use silicon because it balances cost, life and output. Satellites use costly stacked cells that reach close to 50%, the EIA says.
The National Laboratory of the Rockies (NLR) keeps a chart of record lab cell efficiencies since 1976. Every point on it is confirmed by an independent test lab. These records show what is possible, not what you can buy.
Why one shaded cell matters
Cells inside a panel are wired in series, so the weakest cell limits the current of its whole group. A leaf or a chimney shadow covering one cell can drag down far more than its own share.
Panels limit the damage with bypass diodes in the junction box, which route current around a shaded group. Half-cut cells help too. Our guide to shade and solar output shows how designers plan around it.
A shaded or damaged cell can also heat up. This is called a hot spot. Over time it can brown or burn the panel. That is one reason shade from new tree growth is worth watching.
Strengths and weak points of solar cells
Strengths
- No moving parts and no fuel.
- Slow aging: modules often lose less than 1% of output a year, NLR says.
- Silicon is the second most common element in Earth’s crust 3.
- Works with scattered light, not only direct sun.
Weak points
- Thin and brittle, so they can crack if a panel is stepped on or hit.
- Sensitive to shade and heat.
- Cannot be repaired one at a time.
- Makes DC only; a home needs an inverter.
How cells affect panel cost and lifespan
You do not buy cells; you buy panels. Cell type still shapes the quote. Newer n-type cells and back-contact cells usually sit in premium panels. Whether they pay off depends on your roof space and power prices. Our cost per watt guide shows how to compare quotes on a fair basis.
Cells age slowly. NLR says modules often lose less than 1% of output a year, and the loss is hard to measure in the first few years.
The DOE cites a Berkeley Lab survey putting average panel life at 25–35 years in 2025. The panel warranty, not the cell type, is what protects you. Read it on the data sheet.
How cells become panels, and panels a system
At the factory, wafers are cut, treated to form the electric field, printed with metal lines and tested. Cells are then soldered into strings, laid between glass and a back sheet, sealed and framed. The junction box goes on the back.
At your home, you never handle cells. A licensed installer designs the array, gets a permit, mounts the panels and wires them to the inverter. A local inspector and your utility approve the work before you switch on. See how home solar works for the full path.
Keeping cells healthy
Cells are sealed, so care is about the panel around them. Keep shade down by trimming trees before they reach the array. Let rain do most cleaning, and hire a pro if heavy dirt builds up.
Never walk on panels. Cells can crack under the glass with no visible mark. These tiny cracks can grow and cut output over the years. Check your monitoring for a slow, steady drop in one panel or string. Our degradation guide explains normal loss.
Signs of cell damage and when to call a pro
Call your installer if you spot any of these. Many are covered by the panel warranty.
- Brown or burnt spots on a cell (a possible hot spot).
- Snail-trail lines: thin dark streaks across cells, often a sign of cracks.
- Bubbles or peeling under the glass.
- One panel making clearly less than its neighbors in your app.
- Cracked glass after hail or a fallen branch.
Safety rule
Cells make voltage in any light, and broken panels can expose live parts. Do not touch or move a damaged panel. Call a licensed installer.
Standards that apply to cells
Testing. Cell efficiency is measured under fixed lab conditions. NLR’s record chart only accepts results measured to IEC 60904-3 or ASTM G173, at a 25°C reference temperature. Panel data sheets use similar standard test conditions, which is why real-world output is usually lower.
Wiring. Once cells are in a panel on your roof, the National Electrical Code takes over. Article 690 of the NEC covers PV systems; the 2023 edition is the latest summarized by IAEI. Your state or city picks the edition it enforces.
Cell vs panel vs array
| Cell | Panel | Array | |
|---|---|---|---|
| What it is | One semiconductor piece | Dozens of cells behind glass | All the panels in one system |
| Typical output | 1–2 W in the EIA’s rule of thumb | Hundreds of watts; see the data sheet | Several kW on a home |
| Can you replace it? | No | Yes, by an installer | Parts of it, by an installer |
| Glossary | This page | Solar panel | Solar array |
Misconceptions about solar cells
- Myth Solar cells store energy like a battery.
- Reality They make power only while light hits them. Storage needs a separate battery.
- Myth More cells always means more power.
- Reality Cell size and type matter too. Compare panel wattage, not cell count.
- Myth Record lab efficiencies are what you buy.
- Reality Lab records near 50% are for special stacked cells. Home silicon modules run about 20%–22% 3.
- Myth A tiny crack does not matter.
- Reality Microcracks can grow and cause hot spots. Have a damaged panel checked.
Solar cells in SC, GA and VA
Cell technology does not change by state, but heat and rules do. Hot southern summers trim cell output, which a good production estimate includes.
In South Carolina, panel installation is a registered specialty with the Residential Builders Commission, and wiring must be done by a licensed residential electrician or builder 8.
Georgia and Virginia set their own licensing rules; check with your state board.
When cell type should affect your choice
Cell type is worth weighing when:
- Your roof is small, so a higher-efficiency cell fits more watts in the space.
- Part of the roof gets shade, so half-cut cells and good layout matter more.
- You live somewhere hot, so a lower temperature coefficient helps.
- Two quotes are close in price; then compare cell type, warranty and degradation.
Next steps
Questions about photovoltaic cell
What is the difference between a solar cell and a solar panel?
A cell is one small piece of semiconductor making 1–2 watts. A panel, also called a module, is dozens of cells wired together and sealed behind glass in a frame. You buy and install panels. Cells are the working parts inside them.
How many cells are in a solar panel?
It varies by model and cell size. The 435 W Qcells panel in the example above uses 96 half cells. Check the "Cell" row of your panel’s data sheet for its count. Cell count alone does not tell you the output; the panel wattage does.
What are solar cells made of?
Semiconductor material, most often silicon. The DOE says monocrystalline silicon was 96% of global shipments in 2022. Cells are sandwiched between protective materials such as glass and plastic so they survive outdoors for many years.
Can a single solar cell be repaired?
Not in practice. Cells are laminated inside the panel. A cracked or failed cell means replacing the panel. That is work for your installer, and it is often covered by the product warranty. Do not try to open or patch a panel.
What is a half-cut solar cell?
It is a standard cell cut in two. Each half carries half the current, which lowers heat loss in the wiring. The panel is also split into halves, so shade on one half hurts the other less. Many current home panels use half-cut cells.
How efficient is a solar cell?
Home silicon modules turn about 20%–22% of sunlight into electricity, the DOE says. The best silicon lab cells pass 27%. Stacked cells for satellites come close to 50%. The rest of the light reflects or turns into heat.
How long do solar cells last?
They last as long as the panel. NLR says modules often lose less than 1% of output a year. The DOE cites a Berkeley Lab survey putting average panel life at 25–35 years in 2025. Check the warranty on your data sheet.
Why do solar cells make DC and not AC?
The electric field in a cell pushes electrons one way only, so the current flows one way. That is direct current. Homes and the grid use alternating current, so an inverter converts it. See our page on direct current for more.
What are microcracks in solar cells?
They are tiny cracks in the thin silicon, often invisible from the ground. They can come from rough handling, hail or people walking on panels. Over time they can grow, cut output and cause hot spots. An installer can test a suspect panel.
Sources
- US EIA, Solar explained: Photovoltaics and electricity, retrieved .
- US DOE Solar Energy Technologies Office, Solar Photovoltaic Technology Basics, retrieved .
- US DOE Solar Energy Technologies Office, Crystalline Silicon Photovoltaics Research, retrieved .
- National Laboratory of the Rockies (NLR), Best Research-Cell Efficiency Chart, retrieved .
- National Laboratory of the Rockies (NLR), Photovoltaic Lifetime Project, retrieved .
- US DOE Solar Energy Technologies Office, End-of-Life Management for Solar Photovoltaics, retrieved .
- IAEI Magazine, John Wiles, 2023 National Electrical Code and Photovoltaic Power Systems (23 Mar 2023), retrieved .
- SC LLR, Residential Specialty Contractor registration (Solar Panel Installer), retrieved .
- Qcells, Q.TRON BLK S-G3R.12+/BFG 435–450 W data sheet (2025-08 Rev04), retrieved .
Expert review
Written by the HyreSolar Research team. Not yet reviewed by an outside expert. We say so rather than imply a review that has not happened; see our editorial policy.
How the numbers were checked: Cell size, output, construction, market share and efficiencies are from the EIA, DOE and NLR pages cited. The worked example multiplies the voltage and current printed on the manufacturer data sheet for the 435 W class. SC licensing is from sc-local/facts.js.
Suggest a correction. We fix errors and say what changed.