What Is Photovoltaics? How Does a Solar Cell Work?

Photovoltaic modules are becoming increasingly cost-effective and more attractive to both people and governments.

The efficiency of solar cells has significantly increased in recent decades, leading to a huge capacity of installed modules. But many people still have doubts about using this renewable technology.

In this article, we’ll explain what photovoltaics is and how it works. We’ll also list its pros and cons so that you can decide better about using PV systems in your homes and businesses.

What Is Photovoltaics?

The word “photovoltaics” has a Greek root and combines two ideas: photo, which is related to light, and voltaic, which is about voltage.

In 1839, French physicist Alexandre-Edmond Becquerel discovered the photovoltaic effect. However, the first solar cell was made a long time later.

Now, photovoltaics is one of the fastest-growing fields of technology and is revolutionising the way we generate and consume electricity.

Many people confuse photovoltaics, solar cells, solar collectors, and PV modules. Here’s a simple guide to understanding the differences between them:

• Photovoltaics: The technology/science of converting sunlight directly into electricity.

• Photovoltaic: Any item related to photovoltaics, such as a photovoltaic cell or system.

• Solar cell: An integrated semiconductor device that converts sunlight directly into electricity.

• Solar thermal collector: A device that absorbs sunlight’s radiative energy to produce heat, not electricity.

• PV module: A group of connected solar cells to make a single unit. It’s usually called a solar panel.

How Does a PV System Work?

As said earlier, photovoltaic technology uses sunlight energy to generate electrical current.

Solar cells usually include a junction between n-type and p-type semiconductors. When sunlight reaches the junction, photons with enough energy can excite electrons and make them travel through the junction.

So, an electric current is generated by photons. Obviously, this electricity is direct current (DC), which is different from your home’s electric current.

Most of your appliances operate using AC electricity that is usually generated using rotary turbines.

In other words, a solar cell is a direct energy conversion device and is one of the most ingenious technologies to generate power directly within a material.

The electricity generated by panels goes to an inverter to become alternating current suitable for your appliances.

Sometimes, you need to store the electric power to use later (for example, at night). As a result, you need a solar battery for storage and a charge controller to switch the current between the battery and the inverter.

Here is a quick overview of a simple solar photovoltaic system and how it works:

Component	What it does
Solar cell	Converts sunlight into electricity
PV module	Combines multiple solar cells into a practical panel
PV array	Combines multiple modules to increase system power
Inverter	Converts DC electricity into AC electricity
Mounting system	Supports and positions PV modules
Battery	Stores electrical energy for later use when included
Monitoring system	Measures system output and operating conditions
Safety equipment	Provides switching, isolation, and protection

Pros & Cons of Photovoltaic Systems

Each energy system has its own benefits and drawbacks. Let’s see if the advantages of photovoltaics outweigh the disadvantages:

Advantages of Photovoltaics

• Renewable energy source: Sunlight is continually regenerated. So, we can hope to have it for our entire lifespan.

• Zero fuel: Solar cells do not need a continuous fuel supply to generate electricity.

• Low emissions: Electricity generation from PV modules does not pollute the air and is environmentally friendly.

• Scalable: You can install solar panels ranging from small installations to utility-scale power plants.

• Modular: It’s possible to change the capacity of your system by adding modules and equipment.

• Grid-independent: Your home’s dependence on grid electricity will decrease when using PV modules.

• Bill reduction: You can schedule using solar electricity when the grid power price is at its maximum and save money.

• Passive income: You can sell extra electricity to the grid and earn extra money.

• Long lifespan: PV modules usually work for 25 years.

• Low routine maintenance: You just need to clean the surface of solar cells.

• Easy installation: It’s possible to install solar modules on rooftops, ground-mounted structures, parking canopies, façades, and other suitable surfaces.

• No moving parts: Electricity is produced by the material itself without using rotating machinery.

Disadvantages of Photovoltaics

• Intermittent generation: Solar cells’ output varies with sunlight and falls to zero at night.

• Weather dependence: Clouds and other atmospheric conditions can reduce solar cells’ output.

• Upfront investment: Purchasing and installing a complete system might be significant for many families.

• Space requirements: A significant amount of area may be required for larger systems.

• Temperature effects: The efficiency of PV modules decreases as their operating temperature rises.

• Performance degradation: The output of photovoltaic modules gradually declines over time.

• Battery cost: Storage can significantly increase the initial cost of your PV project.

• End-of-life management: PV modules and other equipment require an effective reuse, recycling, or disposal system.

Types of Solar Cells

Here are categories of solar cells:

1. Crystalline Silicon Solar Cells

These are the most common solar cells in the market at the moment. 

Monocrystalline Silicon

Monocrystalline silicon cells are manufactured from high-purity crystalline silicon structures. A single structure, which is usually cubic, repeats throughout the entire body of a monocrystalline solar cell. 

The efficiency of monocrystalline solar cells is higher than that of other solar cell types. They are widely used in residential, commercial, and utility-scale modules.

Polycrystalline Silicon

Polycrystalline silicon cells are made of multiple crystal structures instead of one continuous form.

The process of manufacturing them is cheaper, but their efficiency is significantly lower than that of single-crystal cells.

2. Thin-Film Solar Cells

Thin-film photovoltaic cells have a different structure. They use very thin semiconductor layers deposited onto a substrate.

Common thin-film technologies are:

• Cadmium telluride (CdTe)
• Copper indium gallium diselenide (CIGS)
• Amorphous silicon (a-Si)

3. Emerging Technologies

Fortunately, some new technologies are emerging in the world of solar cells that will revolutionize the market in the future.

Here are some examples:

Perovskite Solar Cells

Perovskites are a fast-growing family of semiconductor materials. Perovskite is a special type of crystal material with a particular atomic structure.

In solar cells, the perovskite layer is usually made from a mixture of elements such as:

• Lead (Pb): helps with light absorption.
• Iodine or bromine: part of the crystal structure.
• Organic or inorganic molecules such as methylammonium or cesium.

They have great potential for reaching high efficiencies at lower prices compared to traditional cells.

Tandem Solar Cells

Tandem cells combine two or more light-absorbing semiconductor structures so that different portions of the solar spectrum can be used more effectively.

Here is a quick comparison between different types of solar cells:

Solar Cell Type	Typical Efficiency	Cost	Main Advantages	Main Limitations
Monocrystalline Silicon	20–24%	Medium–High	High efficiency	Higher cost
Polycrystalline Silicon	15–18%	Low–Medium	Lower cost	Lower efficiency
CdTe Thin-Film	18–22%	Low–Medium	Low material use	Cadmium toxicity
CIGS Thin-Film	15–20%	Medium	Lightweight; flexible options	Complex manufacturing
Amorphous Silicon (a-Si)	6–12%	Low	Lightweight; flexible	Very low efficiency
Perovskite	~20–26%	Potentially Low	Very high potential	Stability issue
Tandem	~25–35%+	High	Very high efficiency	Complex structure

Types of Photovoltaic Systems

PV systems are used in three main methods:

1. On-Grid PV Systems

It’s a grid-connected system that imports/exports power from/to the electrical utility grid.

So, when your PV panels generate electricity, you can use it without relying on grid power. Otherwise, you can use grid power when you don’t have solar electricity.

You can also design it so that you can export the extra solar power generated by your panels to the grid depending on your local regulations.

This type of system doesn’t guarantee solar power whenever you want. However, it has a lower initial cost compared to other types of PV systems.

2. Off-Grid PV Systems

An off-grid system can operate without a utility-grid connection. If you want an off-grid system, you typically need:

• More PV modules
• Charge-control or inverter equipment
• A huge storage system
• Extensive electrical protection
• Energy-management equipment

The cost of such a system is definitely higher than that of on-grid systems.

3. Hybrid Solar Systems

A hybrid PV system combines solar generation with energy storage. Also, it usually offers a grid connection or another backup source.

This configuration allows you to use solar electricity, store excess production, and schedule the solar system based on peak usage hours.

Photovoltaic Cost: A Simple Estimation

You can use a photovoltaic system in different applications:

Category	Type	Typical application
Residential PV	Residential Solar	Homes and small buildings
Commercial PV	Commercial Solar	Offices, retail, factories, institutions
Utility-Scale PV	Solar Farms	Large-scale electricity generation
Building-Integrated PV	BIPV	PV integrated into building components

Depending on your requirements and the quality of your equipment, the project cost can vary significantly.

Apart from your system capacity, you need to consider the following when calculating the cost of your PV system:

• PV modules: Major hardware component and source of generation
• Inverter: Converts and manages electrical power
• Mounting: Attaches modules safely to the building or ground
• Electrical equipment: Provides protection, isolation, switching, and connection
• Labor: Installation and commissioning costs
• Engineering/design: System sizing and technical design
• Permits/grid connection: Depends heavily on location
• Roof work: Can add substantial cost if repairs are required
• Battery: Can significantly increase total project cost
• Monitoring: Tracks production and system health

To get familiar with the costs of a typical PV system, it’s good to look at the following sample:

Imagine you have a villa that uses about 15 kWh of electricity per day. We can assume that the location gets around 5 peak sun hours per day.

Here is a summary of the calculation you need:

Design step	Simple Formula	Result
Estimated villa consumption	—	15 kWh/day
Peak sun hours	Assumption	5 h/day
Initial PV size	15 ÷ 5	3 kW
Allowance for system losses	3 ÷ 0.80	3.75 kW
Rounded system size	—	≈ 4 kW
Panel size	Assumption	500 W
Number of panels	4 ÷ 0.5	8 panels
Total panel capacity	8 × 500 W	4 kW

So, as a simple starting point, this villa would need about eight 500 W solar panels. We can now calculate the cost of your PV system considering the average prices on the market:

Component	Estimated Cost
☀️ 8 × 500 W PV panels	$1,000–$1,400
⚡ 4–5 kW hybrid inverter	$1,000–$1,800
🔋 10 kWh lithium battery	$2,500–$4,000
🔩 Mounting structure	$400–$700
🔌 Cables & protection equipment	$300–$500
👷 Installation & labor	$1,000–$2,000
Estimated total	≈ $6,200–$10,400

Need to size your home’s PV system? Use our free solar PV calculator.

Final Thoughts

Photovoltaics is the effect of electron excitation and flow through a p-n junction by a photon. This phenomenon is the foundation of a large industry that is changing the face of our lives and businesses. Photovoltaic systems have attracted the attention of governments, people, and environmentalists. Solar systems’ size varies from several watts to gigawatts. You can easily install photovoltaic panels on your home’s roof and reduce your electricity bill. You can also export power to the grid depending on your local regulations. If you need advice on the calculation and installation of a PV system, you can count on our help.

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