What Is a Solar Panel and How Does It Work?

A solar panel is a device that converts sunlight directly into electricity using photovoltaic (PV) cells.

Each cell works on a principle called the photovoltaic effect: when photons from sunlight strike a silicon semiconductor, they knock electrons loose and cause them to flow in one direction. That directed flow of electrons is an electric current.

A single cell generates very little power on its own. So manufacturers wire together 60 to 72 cells (or up to 144 half-cut cells in modern designs) to form a solar panel, also called a solar module. Multiple panels wired together, along with an inverter, form a complete rooftop solar system.

Understanding how those cells are manufactured and what separates a well-built cell from a cheap one starts with the raw materials.

What Are Solar Panels Made Of?

Solar panels are built from materials that are, individually, quite ordinary. The engineering is in how they’re combined.

Here are the core components of every solar panel:

• Silicon – the semiconductor at the heart of every PV cell, derived from quartz sand
• Tempered glass – a specially formulated, low-iron, high-transmittance front cover (typically 3–4 mm thick) that protects cells from weather while letting maximum light through
• EVA (Ethylene Vinyl Acetate) – a transparent encapsulant that bonds the layers together and seals cells from moisture, oxygen and mechanical stress
• Backsheet film –  a multi-layer polymer on the rear of the panel providing electrical insulation and weather protection; some premium panels use dual-glass instead
• Aluminium frame –  anodised or powder-coated for corrosion resistance; provides structural support and rooftop mounting points
• Silver and copper –  fine silver paste grid lines conduct electricity out of the cells; copper ribbons and busbars carry it to the junction box
• Junction box –  a weatherproof enclosure on the panel’s rear containing bypass diodes and output connectors

The quality of every one of these materials affects real-world performance. Cheaper panels cut corners on silver purity, EVA formulation or junction box components and these trade-offs show up years later as premature degradation or failure.

How Solar Panels Are Made: The Step-by-Step Manufacturing Process

Solar panels go through 10 main production stages, from raw quartz sand to a finished, certified module ready for your rooftop:

1. Silicon purification  quartz sand refined to 99.9999% pure polysilicon
2. Ingot formation  silicon cast into crystalline blocks
3. Wafer slicing  ingots cut into discs 160–200 micrometres thin
4. Doping  wafers treated to create a P-N junction
5. Anti reflective coating  silicon nitride layer applied to maximise light capture
6. Metal contact printing  silver paste grid lines screen-printed and fired onto cells
7. Cell-level testing  every cell measured under a calibrated solar simulator
8. Cell stringing cells wired together in series to build voltage
9. Module lamination layers fused under heat and vacuum pressure
10. Framing and final testing aluminium frame fitted; EL imaging and flash test performed

Now let’s walk through each stage in detail.

Step 1: Silicon Purification From Sand to Semiconductor

Everything begins with raw quartz sand or quartzite rock, which is primarily silicon dioxide (SiO₂). This material is heated in an arc furnace at over 2,000°C, which strips away the oxygen and reduces the rock to metallurgical-grade silicon roughly 98–99% pure.

That sounds impressive, but it’s still not nearly pure enough for solar cells. The silicon goes through a second, more precise purification stage using the Siemens process: a chemical method involving trichlorosilane gas that removes nearly all remaining impurities. The result is polysilicon with a purity of 99.9999% what the industry calls “six-nines” purity. This is the foundational raw material of every solar cell.

Think of it like purifying water. Tap water is fine for drinking, but a semiconductor needs the equivalent of ultra-pure laboratory-grade water every trace of impurity must go.

According to MNRE data, India’s domestic solar module production capacity reached 150.26 GW as of April 2026, though domestic polysilicon production is still developing; most Indian manufacturers currently source polysilicon from the global market.

Step 2: Forming Silicon Ingots

The purified polysilicon is melted in a quartz crucible and shaped into solid blocks called ingots. How this step is performed determines the fundamental type of solar cell you end up with.

Monocrystalline ingots are grown using the Czochralski process. A tiny “seed” crystal is dipped into the molten silicon and then slowly pulled upward while rotating. As it rises, silicon atoms align themselves with the seed’s crystal structure, growing a single large crystal of uniform molecular alignment, a cylindrical ingot that can be over a metre long. This precise, ordered structure gives monocrystalline cells their characteristic uniform dark appearance and is the foundation of their higher efficiency.

Polycrystalline ingots are made by simply pouring molten silicon into square molds and letting it cool and solidify. Multiple silicon crystals form in random orientations as the melt cools; you can see the resulting grain boundaries in the finished panel’s blueish, speckled appearance. The process is faster and cheaper, but the irregular crystal structure creates more obstacles for electrons to cross, which limits efficiency.

Step 3: Slicing Silicon Wafers

The ingots are sliced into ultra-thin discs called wafers using precision diamond wire saws, extremely fine wires coated in diamond particles that cut with minimal material loss.

Standard silicon wafers are just 160-200 micrometres thick, roughly the width of two human hairs. Achieving this precision at scale, across millions of wafers, is one of the manufacturing industry’s quiet engineering achievements.

After slicing, the wafers are cleaned to remove any contamination from the cutting process, then chemically etched to create a textured surface. Under magnification, this texture looks like a field of tiny pyramids. These pyramids reduce light reflection from roughly 35% (on a flat surface) down to under 5%, dramatically increasing the amount of sunlight the cell can absorb.

Step 4: Creating the P-N Junction (Doping)

This is the step that transforms a passive silicon disc into an electricity-generating solar cell.

Pure silicon is a poor conductor. To make it useful, manufacturers “dope” the wafers deliberately introducing tiny amounts of other elements to change their electrical properties:

• One surface is treated with phosphorus (which has one more electron than silicon), creating an excess of free electrons. This is the N-type layer (N for negative charge carriers).
• The other surface is treated with boron (which has one fewer electron), creating “hole” spaces where electrons are missing. This is the P-type layer.

The boundary where N-type meets P-type is called the P-N junction. When sunlight photons strike this junction, they energise electrons and push them across the boundary and that one-way movement of electrons is an electric current.

In plain terms: doping turns silicon into a one-way valve for electrons and sunlight is what opens it.

Step 5: Anti-Reflective Coating and Metal Contacts

Two more things happen to each wafer before it’s ready to be wired into a panel.

First, a thin layer of silicon nitride is deposited on the cell’s surface using a process called plasma-enhanced chemical vapour deposition (PECVD). This layer serves double duty: it gives solar cells their distinctive dark blue or black colour and it acts as an anti-reflective coating that keeps light from bouncing off the surface.

Second, the electrical contacts are screen-printed onto the cell using fine silver paste. A grid of thin lines (called “fingers”) is printed across the front to collect electrons; a broader contact is printed on the rear. The cell then goes through a high-temperature firing step (around 800°C) that burns off the paste’s organic binders and permanently bonds the silver to the silicon surface.

The silver content in these contacts is significant. Silver is one of the most expensive materials in a solar panel. Higher-quality panels use finer, better-formulated paste that conducts more efficiently and degrades less over time.

Step 6: Individual Cell Testing

Before any cell goes near a panel assembly line, it’s tested individually under a solar simulator, a controlled light source calibrated to exactly replicate Standard Test Conditions (STC): 1,000 W/m² irradiance at 25°C.

This test measures each cell’s actual power output, open-circuit voltage, short-circuit current and efficiency. Cells are sorted into efficiency bins; those that underperform are rejected or downgraded to lower-tier products.

This individual cell testing is what separates a manufacturer with genuine quality control from one that does only module-level testing. When you buy from a reputable brand, you’re buying cells that passed this test, not just a panel that roughly met specs in aggregate.

Step 7: Stringing and Interconnecting the Cells

Tested cells are now electrically connected into strings using thin copper ribbons soldered from the front contact of one cell to the rear contact of the next. This series connection adds up voltage across the string.

A standard 60-cell panel is arranged as 10 strings of 6 cells. Modern high-wattage panels use half-cut cell technology; each cell is laser-cut in half before stringing, which reduces internal current losses and improves shade performance. A 120 half-cut cell panel produces essentially the same power as a 60-cell design but with better real-world efficiency.

Premium panels now use multi-busbar (MBB) designs 9 to 16 thin busbars per cell instead of 3–5 wider ones. More busbars mean shorter electron travel distances, lower resistance losses and better performance when part of the panel is shaded.

Step 8: Module Assembly and Lamination

With cell strings assembled, the panel’s protective layer stack is built up in order:

1. Tempered front glass (faces the sun)
2. EVA encapsulant sheet
3. Solar cell strings
4. Second EVA encapsulant sheet
5. Backsheet film (or rear glass for bifacial panels)

This entire assembly goes into a lamination machine that applies heat (around 150°C) and vacuum pressure simultaneously. The EVA melts, flows around every cell and bonds all layers into a single sealed unit completely protecting the cells from moisture, oxygen and physical stress.

The tempered glass used here is not standard window glass. It’s formulated with low iron content for maximum light transmittance, tempered for impact resistance and tested to withstand hail, high winds and thousands of thermal expansion and contraction cycles.Panels sold in India must meet IEC 61215 and IEC 61730 standards to ensure they can survive extreme heat, cold and mechanical loads.

Step 9: Framing and Junction Box Installation

The laminated panel is fitted with an aluminium frame anodised or powder-coated to resist corrosion through monsoon seasons and coastal humidity. The frame protects the glass edges from chipping and provides the mounting holes for roof installation hardware.

On the rear, a weatherproof junction box is bonded to the backsheet. Inside the junction box are bypass diodes; these are more important than they appear. If one section of the panel is shaded, a bypass diode lets current flow around that section rather than losing power from the entire panel. Junction box quality affects both safety and long-term performance; a failed junction box is one of the most common causes of fire in low-quality installations.

Step 10: Final Testing and Quality Certification

Every finished panel must pass two final checks.

EL (Electroluminescence) imaging: The panel is energised and photographed with an infrared camera. Healthy cells glow uniformly. Micro-cracks, dead cells, delamination or cold solder joints appear as dark patches defects completely invisible to the naked eye. Any panel with EL defects is rejected before it leaves the factory.

Flash test (STC test): The panel is exposed to a precisely calibrated flash of light and its actual power output is measured and labelled. Reputable manufacturers label panels with their real measured output (e.g., 540W ±3W). Some lower-grade manufacturers use inflated ratings; a 540W label that tests at 510W is a 30W shortfall that compounds across your entire system.

For Indian-made solar products, mandatory certifications include BIS (Bureau of Indian Standards) for products sold in India, IEC standards for performance and safety and ALMM (Approved List of Models and Manufacturers),a MNRE registry that verifies domestic manufacturing claims. As of early 2026, the government mandated that projects commissioned after June 2026 must use solar cells from the ALMM list.

Solar Panel Technologies in 2026: PERC, TOPCon, HJT and Bifacial

Understanding how panels are made helps you decode the technology labels you’ll encounter when shopping. Here’s what each actually means and why it matters for an Indian buyer in 2026.

P-Type vs. N-Type Silicon: The Foundation

Older panels use P-type silicon as the cell base boron-doped silicon where the current flows through “holes.” Most panels sold in India before 2023 were P-type.

The market is now shifting to N-type silicon (phosphorus-doped), which has inherently lower impurity sensitivity and degrades more slowly over time. TOPCon and HJT, the two leading premium technologies are both N-type.

PERC (Passivated Emitter and Rear Cell)

PERC was the dominant technology in India from roughly 2018 through 2023. It adds a passivation layer on the rear of a standard P-type cell that reflects unabsorbed light back through the silicon for a second chance at generating electricity. Efficiency: 20–22%. Still widely sold and affordable; a solid choice for budget-conscious buyers with adequate rooftop space.

TOPCon (Tunnel Oxide Passivated Contact)

TOPCon is the mainstream premium technology in 2026.TOPCon technology is considered one of the best solar technologies in 2026 due to its higher efficiency and lower degradation rates. It adds an ultra-thin tunnel oxide layer on the N-type cell’s rear that dramatically reduces electron recombination losses, electrons that would otherwise “leak” back before reaching the contacts. Efficiency: 22–24%. Annual degradation: approximately 0.4% (vs 0.55% for PERC). Better temperature performance. Major Indian manufacturers including Waaree Energies, Adani Solar and Vikram Solar have launched TOPCon product lines.

HJT (Heterojunction Technology)

HJT combines crystalline silicon with thin layers of amorphous silicon on both cell surfaces, creating an exceptionally effective passivation structure. Efficiency: 23–25%. Temperature coefficient: -0.24 to -0.26%/°C the lowest of any mainstream technology, meaning the least efficiency loss in summer heat. Currently the premium option, priced above TOPCon, but the technology of choice where maximum performance per square metre is the priority.

Bifacial Panels

Bifacial panels generate electricity from both sides, the standard front face and the rear face, which captures reflected light (albedo) from the ground or rooftop surface.Bifacial N-Type TOPCon modules can boost energy yields by 10% to 30% compared to monofacial panels, depending on the reflectivity of the surface beneath. Increasingly common in commercial rooftop and ground-mount systems across India.

Technology Comparison at a Glance

For most Indian homeowners in 2026, TOPCon is the sweet spot meaningfully better than PERC in real-world heat performance without the premium price of HJT.

What to Look for When Buying Solar Panels in India

Knowing how panels are manufactured puts you in a much stronger position when comparing products. Here is the non-negotiable checklist:

• BIS IS 14286 certification mandatory for any panel sold for grid-connected use in India; ask for the certificate, not just a claim
• ALMM listing for systems availing government subsidies, panels must come from MNRE’s Approved List of Models and Manufacturers
• IEC 61215 and IEC 61730 international performance and safety standards; both should be present
• Performance warranty minimum 80% output after 25 years; TOPCon/HJT panels from reputable brands now offer 87–90% guarantees
• Product warranty minimum 12 years against manufacturing defects; top brands offer 15–25 years
• Temperature coefficient aim for -0.30%/°C or better; in states with peak summer temperatures of 40–47°C, every 0.05% difference compounds meaningfully over 25 years
• Annual degradation rate look for 0.4%/year or less; avoid panels with published rates above 0.6%
• Multi-busbar (MBB) design 9+ busbars for better shade tolerance and lower resistance losses
• EL test disclosure ask whether the manufacturer performs EL imaging on every panel; reputable manufacturers do

India’s Solar Manufacturing Boom: What It Means for Buyers

India’s domestic solar manufacturing sector has undergone a significant transformation in recent years. Under the ALMM mandate, solar PV module capacity in India has reached 172,592 MW as of March 2026, a dramatic increase from under 10 GW in 2018. Domestic cell manufacturing capacity has grown to roughly 27 GW by December 2025. Gujarat remains the hub of this manufacturing boom, hosting about 45% of India’s overall solar cell and module production lines.

This scaling of domestic solar panel manufacturing is supported by the ₹24,000 crore Production Linked Incentive (PLI) scheme, which funds the development of integrated giga-factories.

For buyers, this means more options from Indian-made, BIS-certified, ALMM-listed panels often with competitive pricing and better after-sales support than imported alternatives. Leading domestic manufacturers include Waaree Energies, Adani Solar, Vikram Solar, Solex Energy, Rayzon Solar and Bluebird Solar.

Government Solar Subsidies in India 2026: What’s Available

Now that you understand what makes a quality solar panel, here’s the financial case for installing one.

PM Surya Ghar Muft Bijli Yojana

Launched by Prime Minister Narendra Modi in February 2024 with a total outlay of ₹75,021 crore, PM Surya Ghar Muft Bijli Yojana aims to install rooftop solar systems on one crore (10 million) homes by 2027. Beneficiaries receive up to 300 units of free electricity per month and a substantial government subsidy on installation cost.

As of March 2026, the scheme has benefited over 32 lakh households through rooftop solar installations across India.

The Central Financial Assistance (CFA) subsidy structure is:

The subsidy covers approximately 30–40% of a typical 3 kW residential system cost, making 3 kW the sweet spot for most residential customers. Subsidy is transferred directly to your bank account not to the installer protecting you from overcharging.

A 3 kW solar system costs approximately ₹1,96,000 before subsidy. After deducting the ₹78,000 PM Surya Ghar central subsidy, your net investment is approximately ₹1,18,000.

State-Level Top-Up Subsidies

Many states offer additional subsidies on top of the central government amount.For example, Gujarat offers an additional ₹40,000 state subsidy, meaning a 3 kW system in Gujarat could see total subsidies exceed ₹1,00,000. Uttar Pradesh offers an additional ₹15,000–₹30,000 state top-up in 2026. Check your state’s DISCOM or MNRE portal for current state-specific amounts.

PM KUSUM for Farmers

The PM KUSUM (Pradhan Mantri Kisan Urja Suraksha evam Utthaan Mahabhiyan) scheme provides subsidies specifically for farmers installing solar water pumps and solar feeders, reducing irrigation costs and dependence on diesel pumps. Subsidy levels vary by state; check the MNRE portal for your state’s current PM KUSUM offering.

Net Metering

Net metering is mandated under the Electricity (Rights of Consumers) Rules 2020 for all DISCOMs. This means surplus electricity your system generates is exported to the grid and credited against your bill reducing your effective payback period. Net metering is available for both residential and commercial solar installations across India.

How to Apply for Solar Subsidy in India (Step by Step)

The application process for PM Surya Ghar Muft Bijli Yojana is fully online:

Step 1: Visit pmsuryaghar.gov.in, click “Apply Now” under the Consumer tab and register using your mobile number, electricity consumer number and email ID. Complete OTP and email verification to activate your account.

Step 2: Fill in your personal details, property address, rooftop specifications and preferred system capacity. Upload scanned copies of your Aadhaar card and latest electricity bill.

Step 3: Obtain technical feasibility clearance from your DISCOM.

Step 4: Choose a vendor from the MNRE-empanelled vendor list available on the portal. Your installer will handle system design, procurement and installation.

Step 5: After installation and net metering commissioning by your DISCOM, upload the commissioning report to the portal and enter your bank details.In 2026, processing times have improved to 15–20 days in most states due to digitalisation.

How to Choose a Solar Installer in India

The right installer makes as much difference as the right panel. Before signing anything, verify:

• MNRE empanelment only empanelled vendors can process government subsidy applications; ask for their empanelment number and verify it on the MNRE portal
• ALMM-listed panels your installer should be sourcing from MNRE’s approved manufacturer list
• Site assessment before quoting a professional installer visits your rooftop to assess available area, shading, roof angle and your consumption pattern; avoid anyone who quotes without a physical visit
• DISCOM liaison experience grid-connected solar requires net metering approval from your DISCOM; experienced installers handle this routinely
• After-sales service in your city ask specifically about local service presence; a panel issue shouldn’t require a technician from another state
• Subsidy documentation support the best installers manage the entire application and commissioning report submission

What Happens After Installation?

Solar panels are only part of the system. A complete rooftop solar installation includes:

• Solar panels generate DC electricity from sunlight
• Inverter converts DC to AC electricity for use in your home; string inverters are most common for residential; microinverters offer better shade performance
• Net meter installed by your DISCOM; measures electricity you export to the grid and import from it
• Monitoring system most modern inverters include a Wi-Fi monitoring app showing your real-time and historical generation

Maintenance requirements are minimal: clean panels with water every few weeks during dusty or dry seasons and schedule an annual inspection of wiring, connections and inverter health.

Frequently Asked Questions

What is the main material used to make solar panels?

The main material used to make solar panels is silicon, a semiconductor element refined from ordinary quartz sand. It is purified to 99.9999% purity before being shaped into wafers that form the active electricity-generating cells inside every solar panel.

How is a solar panel made step by step?

Solar panels are made through 10 main stages: silicon purification from quartz sand; forming silicon ingots (monocrystalline or polycrystalline); slicing ingots into thin wafers; doping wafers with phosphorus and boron to create a P-N junction; applying an anti-reflective silicon nitride coating; screen-printing silver paste metal contacts; testing each cell under a solar simulator; stringing cells together in series; laminating the assembly between tempered glass and a backsheet under heat and pressure; and performing final EL imaging and a flash power test before certification.

What is the difference between PERC, TOPCon and HJT solar panels?

PERC, TOPCon and HJT represent three successive generations of solar cell technology. PERC adds a reflective passivation layer to P-type silicon cells, achieving 20–22% efficiency. TOPCon uses N-type silicon with a tunnel oxide passivation layer, achieving 22–24% efficiency and a lower annual degradation rate of ~0.4%. HJT combines crystalline and amorphous silicon for 23–25% efficiency and the lowest temperature coefficient (-0.25%/°C) of any mainstream technology. For most Indian homeowners in 2026, TOPCon offers the best balance of performance and cost.

Are solar panels manufactured in India?

Yes, India is now a major solar panel manufacturer. Domestic module production capacity reached 172,592 MW as of March 2026, supported by the ₹24,000 crore PLI scheme. Leading manufacturers include Waaree Energies, Adani Solar, Vikram Solar, Rayzon Solar and Solex Energy. From June 2026, government-subsidised projects must use panels from MNRE’s ALMM (Approved List of Models and Manufacturers).

How much government subsidy is available for solar panels in India in 2026?

The PM Surya Ghar Muft Bijli Yojana provides a central subsidy of up to ₹78,000 for residential rooftop solar installations — ₹30,000 for 1 kW, ₹60,000 for 2 kW and ₹78,000 (fixed maximum) for 3 kW and above. This subsidy is transferred directly to your bank account within 15–20 days of DISCOM commissioning approval. Many states offer additional top-up subsidies on top of the central amount.

How long do solar panels last in India?

Quality solar panels typically last 25–30 years. Most reputable panels carry a 25-year performance warranty guaranteeing at least 80% of rated output; TOPCon and HJT panels from premium manufacturers now guarantee 87–90% output at 25 years. With proper maintenance, many panels continue operating productively beyond 30 years with gradually declining efficiency.

Do solar panels work in India’s summer heat?

Yes, solar panels generate electricity in high temperatures, though output decreases as panel temperature rises above 25°C. This loss is quantified by the temperature coefficient, the efficiency reduction per °C above the rated temperature. In cities where temperatures reach 42–47°C in summer, choosing a TOPCon panel (-0.30%/°C) over a PERC panel (-0.35%/°C) can mean meaningfully more generation over the system’s lifetime. HJT’s -0.25%/°C coefficient offers the best heat performance of any mainstream technology.

How many solar panels do I need for a home in India?

The number of panels depends on your monthly electricity consumption and available rooftop space. A household using 300 units per month typically needs a 3 kW system, which requires 6–8 panels at current wattages (400-550W per panel). A higher-consumption home using 500 units per month needs a 5 kW system of approximately 10 – 12 panels. A site assessment from an MNRE-empanelled installer will calculate the right system size for your specific usage and rooftop.

What certifications should I check before buying solar panels in India?

For panels sold in India, look for BIS IS 14286 certification (mandatory for grid-connected use), ALMM listing (required for subsidy-eligible projects from June 2026 onwards) and IEC 61215/IEC 61730 international performance and safety standards. Always ask for the actual certificate not just the manufacturer’s claim and verify ALMM listing on the MNRE portal.

You may also read our blog “How Solar Panels Work: the complete guide to understanding solar energy“

Ready to Go Solar? Here’s Your Next Step

You now know exactly what goes into making a solar panel from purifying quartz sand into six-nines polysilicon, to the Czochralski crystal growth process, wafer slicing, P-N junction doping, multi-busbar stringing, lamination and the EL imaging test that certifies every panel before it leaves the factory.

More importantly, you know how to use that knowledge: choose BIS-certified, ALMM-listed panels with a low temperature coefficient, check for EL test disclosure, verify your installer’s MNRE empanelment and don’t pay for a system until you’ve had a proper rooftop site assessment.

With central government subsidies of up to ₹78,000 available, state-level top-ups in many states, net metering mandated across India and domestic manufacturers now producing world-class TOPCon panels the financial and practical case for going solar in India in 2026 has never been clearer.