Photovoltaic Cell Manufacturing: 9 Steps to a Graded Cell

According to PVEducation, silicon coming out of the arc furnace is already 98 % pure, and that is still far too impure to make a solar cell.

This guide starts at the point where cell production ends and module assembly begins, then walks the nine steps in order. It shows how finished PERC, TOPCon and back-contact cells differ and explains how flash testing sorts cells into efficiency grades.

A spec table compares the cell formats to check before ordering, and the final part covers why grade matters more when cells go into a small panel. Buyers who already know the format they need can browse loose solar cells by format and efficiency, which LinkSolar sources with direct factory-side QA.

What is photovoltaic cell manufacturing, and where does it end?

Photovoltaic cell manufacturing is the chain of steps that turns purified silicon into a finished solar cell with a junction, a coating and metal contacts, tested and sorted by output. It runs from the raw silicon feedstock to the moment each cell is measured and graded.

According to the U.S. Department of Energy, most commercial PV modules use crystalline silicon. That silicon passes through three stages before it becomes a cell, and each stage usually runs in its own plant.

• Polysilicon: Metallurgical-grade silicon made from quartz sand is refined with hydrogen and chlorine into high-purity rods or beads.
• Ingot and wafer: The polysilicon is melted and formed into an ingot, which diamond-coated wire saws slice into very thin wafers.
• Cell fabrication: Each wafer is textured, doped, coated and given screen-printed contacts so it can generate and carry current.

Stringing the cells and laminating them into a panel is the next stage, module assembly, and is a separate process that the DOE places in another facility. Cell manufacturing ends when the tested cell leaves the cell line as a loose part.

At that point, the buyer receives a flat, brittle cell with a front and rear contact pattern, or rear contacts only on a back-contact cell. Each cell carries a rated power, a voltage and a current measured at standard test conditions, plus a grade that reflects how it tested.

The junction and the printed contacts are what let the cell deliver usable current. For the physics behind that, see how a solar cell turns light into current.

The grade is the part of the result a loose-cell buyer can specify. Two cells from the same line can land in different efficiency bins, so the rated power on the listing and the bin behind it are worth confirming before an order.

What are the solar cell manufacturing steps, from polysilicon to a finished cell?

Solar cell manufacturing runs in nine steps, three of them upstream material work and six on the wafer itself, and the order is the same for a large-format cell and a small one later cut into strips. Steps 1 to 3 set the purity and crystal type of the wafer, steps 4 to 8 build the junction, coating and contacts on it, and step 9 assigns each cell its rated output. Each step below names what it leaves behind for the next one.

According to the U.S. Department of Energy, silicon cells start as polysilicon that is melted into ingots and sliced into wafers before cell fabrication begins. The purity figure in step 1 comes from PVEducation on refining silicon, and the wafer steps follow PVEducation's account of screen-printed solar cells, the most mature fabrication technology in terrestrial modules.

1. Refine the polysilicon: Metallurgical-grade silicon, made from quartz in an arc furnace and already 98 % pure, is refined with hydrogen and chlorine into high-purity polysilicon rods or beads.
2. Grow the ingot: The polysilicon is melted and either pulled from a seed into a round monocrystalline ingot or cooled slowly from the bottom up into a large-grained multicrystalline block.
3. Saw the wafers: Diamond-coated wire saws slice the ingot into very thin wafers, and the silicon lost as sawdust is called kerf.
4. Texture the surface: A chemical etch removes the saw damage and leaves small light-trapping pyramids on mono wafers, a step that is only marginally effective on multicrystalline grains.
5. Diffuse the junction: Phosphorus diffused into the front surface forms the emitter and the junction, and edge isolation by plasma etch, laser or masking keeps the front and rear apart.
6. Coat the front: A silicon nitride or titanium dioxide anti-reflective coating lets more light in, passivates the surface and gives the cell its blue color.
7. Print the contacts: Silver contacts are screen-printed on the front over the coating, and an aluminum layer is printed across the rear.
8. Fire the cell: A furnace fires the front contacts through the coating so they bond to the silicon and alloys the rear aluminum into a back surface field.
9. Test and bin: Each finished cell is typically measured for output and sorted into an efficiency bin, which becomes the grade a buyer of loose cells receives.

A cell that is later cut into halves or strips passes through all nine steps first, so every cut piece comes from a cell that has already been tested. The cell architectures in the next section tune these same steps, and the difference a buyer sees is where the contacts sit.

Why do PERC, TOPCon and back-contact cells look and solder differently?

PERC, TOPCon and back-contact cells go through the same nine manufacturing steps, each tuned for its own architecture, and the difference a buyer sees is where the metal contacts sit and how thin they are. That contact layout also sets how the cell gets tabbed, by hand with a soldering iron or on a stringing machine.

PERC is the standard format, with busbars printed on the front, and it is what most production modules use. On the LinkSolar cell listings it appears as a 166 mm mono PERC cell rated at 6.04 W, a bifacial version and several small formats. Small-format PERC and mono cells tab by hand with a normal soldering iron, which makes them the usual choice for hand-built panels.

TOPCon is an N-type format, which typically reverses the polarity of the doped layers compared with a p-type wafer. The 182 × 183.75 mm TOPCon cell on the listings is rated at 8.54 W and 25.5 % efficiency. Its front carries thin round-wire multi-busbar contacts, the same layout used on modern half-cut PERC cells.

Those thin multi-busbar contacts are designed for stringing machines, so hand builds go better with small-format PERC. A buyer planning manual assembly reads the contact layout on the listing before choosing a format.

Back-contact cells, also called IBC cells, put both contacts on the rear, so the front has no grid and output per area is higher. The 125 mm back-contact full cell is listed at 3.78 W and 24 %+ efficiency, and the range comes as full cells or as cut halves, thirds, sixths and center strips. The quickest visual check is the front: a plain blue surface with no silver lines.

The choice between monocrystalline and multicrystalline silicon starts at the texturing step. According to PVEducation, the chemical etch leaves light-trapping pyramids on monocrystalline wafers but is only marginally effective on multicrystalline grains. That is one reason monocrystalline formats fill most of the live LinkSolar range, with polycrystalline cells appearing only among small strips and packs.

How are solar cells tested and sorted into efficiency grades?

Solar cells are tested and sorted after firing: in typical line practice, every cell is flash-tested under a calibrated light pulse, its current, voltage and power are recorded, and it goes into an efficiency or power bin. Visible or hidden defects move a cell into a lower grade. The bin and the grade together describe the cell a buyer of loose cells actually receives.

The flash test reads the cell's IV curve, the plot of current against voltage, and takes the maximum power point from it. Cells with close readings share a bin, so each bin holds cells within a narrow band of measured output. Grade labels such as A-grade vary by supplier.

A cell moves down a grade for reasons a buyer can check in the supplier's images or on arrival. Typical reasons are:

• Chipped edges: Small breaks along the edge can grow into cracks when the cell is handled or soldered.
• Color variation: Uneven shades of the anti-reflective coating show across one cell or between cells in a lot.
• Print defects: Broken, smeared or misaligned contact fingers and busbars come from the screen-printing step.
• Microcracks: Hairline cracks inside the silicon show up under EL (electroluminescence) imaging and stay hidden from the eye.

Binning works like matching batteries before wiring them in series, because one weak unit sets the pace for the string. LinkSolar's small-cell listings state the rule in plain terms: the smallest cell limits the current of the whole string.

The live LinkSolar listings show what this testing looks like on a product page. Two small-format listings describe their cells as A-grade, and the back-contact listings state EL testing with an IV curve for every order, plus laser-scored, sealed edges with a low microcrack rate. For any grade label, ask the supplier what it means in measured terms, including the power spread inside the bin and whether EL images come with the lot.

The same checks carry into finished products. The production QA for custom mini panels with EL imaging and IV binning lists visual inspection and serialization alongside those two tests.

Specs to compare before you order loose solar cells

The specs to compare before you order loose solar cells are the format, rated power, voltage at max power, efficiency, contact layout and whether the cell hand-solders. Grade, wafer thickness, busbar count and packing are then confirmed with the supplier in writing, because those details vary by lot and format.

Rated power is the listed wattage of one cell at STC, and voltage at max power sets how many cells go in series. Each silicon cell gives roughly 0.5 to 0.6 V under load regardless of size, so a larger format mainly adds current. The contact columns show how the cells get wired: thin multi-busbar cells are made for stringing machines, while small-format PERC cells tab by hand with a normal soldering iron.

Specs to compare before you order loose solar cells

Cell	Size (mm)	Rated power	Voltage at max power	Efficiency	Front contacts	Hand-solder?
Small PERC	52 × 52	0.6 W	0.55 V	22 %	Front busbars	Yes
Mono PERC	166 × 166	6.04 W	Confirm	22 %	Front busbars	Confirm
Bifacial PERC	166 × 166	5.89 W	Confirm	21.5 %	Front busbars	Confirm
N-type TOPCon	182 × 183.75	8.54 W	0.62 V	25.5 %	Thin multi-busbar	No, machine stringing
Back-contact	125 × 125	3.78 W	0.625 V	24 %+	None (rear only)	With rear tabbing
Back-contact	166 × 166	6.60 W	0.60 V	24 %+	None (rear only)	With rear tabbing

Figures from the live LinkSolar cell listings on 25 September 2026, at STC; typical values, confirm per lot.

For cells going into a product you sell, ask the supplier for its test report.

A table entry marked Confirm is a value to request per lot before the order is placed. The six checks below turn the table into written questions, and the guide on how to choose a solar cell supplier covers how to vet the source that answers them.

• Grade: Ask what the grade label means in measured terms, because labels such as A-grade vary by supplier.
• Efficiency bin: Ask which bin the lot comes from and the power spread inside that bin, since the smallest cell limits the current of the whole string.
• Contact layout: Ask for the busbar count or rear contact pattern, which decides whether the cells tab by hand or need a stringing machine.
• Wafer thickness: Ask for the thickness of the lot in writing, as it varies by format and sets how carefully the cells are handled.
• Full or cut cells: Ask whether cells ship full or cut and what the cut tolerance is, because cut cells keep the voltage and divide the current.
• Packing: Ask how cells are separated and protected in transit, so edges, fingers and busbars arrive free of bending or contamination.

Each listing in the range of PERC, TOPCon and back-contact cells in stock shows the cell format, nominal wattage and pack options, and LinkSolar confirms grade, bin and packing before you order. For production quantities, custom cuts or pre-tabbed strings, send the drawing or the target voltage and current with the request.

Why does cell grade matter more when the cells go into a small custom panel?

Cell grade matters more in a small custom panel because the panel has only a handful of cells in one series string, so one low-binned or cracked cell pulls down the current of the whole panel. A large panel has many cells to average out small differences. A small panel has no spare cells to do that.

The figures on the live LinkSolar cell pages show how few cells are involved. Each silicon cell gives roughly 0.5 to 0.6 V under load regardless of size, and cell size sets the current. Typically 8 to 12 cells in series feed a regulator for 5 V USB output, and 36 cells in series reach a 12 V charging panel.

In a series string, every cell carries the same current, so the weakest cell sets the limit for the rest. The same logic applies to size: keep every cell in a string the same size, because the smallest cell limits the current of the whole string.

Cut cells keep the voltage and divide the current, so a half cell or a strip carries a fraction of the full cell's current. Cut pieces taken from one matched lot keep that fraction even across the string. Mixing pieces from different lots or bins brings back the weak-cell problem at a smaller scale.

For small panels, LinkSolar works as a sourcing partner on the China side with direct factory-side QA. Each order starts with one specification review, where the target voltage and current set how many cells go in series and which cells are matched to them. Production then goes through EL imaging, IV binning and visual inspection, followed by one pre-shipment inspection with photo and video evidence.

Buyers who want cells laminated into a custom panel send the drawing or the target voltage and current. For builds that fit a standard size, mini solar panels with the cells already connected are the shorter route. The guide to sizing a small solar panel for a device helps set that target voltage and current before the specification review.

FAQ: photovoltaic cell manufacturing

Can I make my own solar cells?

A working silicon solar cell needs a clean-room line with a diffusion furnace, a vacuum coater, a screen printer and a firing furnace. Classroom dye-sensitized or copper-oxide cells work at teaching scale only, at a tiny fraction of a silicon cell's output.

The practical route is to buy finished cells and build the panel. Start with small cells and strips for hand-soldered builds, then follow a guide to building a panel from finished cells.

What is the difference between solar cells and solar panels?

A solar cell is one silicon wafer that gives roughly 0.5 to 0.6 V under load, whatever its size. A solar panel is many cells wired in series and sealed into one unit.

According to the U.S. Department of Energy, cell fabrication and module assembly usually happen at separate facilities. Panel assembly starts where cell making ends, with a tested, graded cell.

Where can I get solar cells?

Solar cells are available from the LinkSolar cell collection, where every listing shows the cell format, nominal wattage and pack options. Stock ships from inventory, and small formats come in packs of 10 to 100.

For custom cuts or pre-tabbed strings, send LinkSolar the drawing or the target voltage and current.

Why are most solar cells blue or black?

The color of a solar cell comes from its anti-reflective coating and surface texture, which let more light into the wafer. According to PVEducation, common coatings are silicon nitride and titanium dioxide.

Back-contact cells put both contacts on the rear, so the front shows a plain surface with no grid.

Next step

Send LinkSolar the cell format, the target voltage and current, the quantity range and whether you need full or cut cells, and LinkSolar confirms the grade, efficiency bin and packing before you order. To start, request a quote for cells or a custom panel. If a standard format fits your build, compare the finished cells ready to tab first.