Adelmo Alves

The History of Photovoltaic Technology: Key Milestones

The journey to photovoltaic technology as we know it today has been shaped by many key milestones and groundbreaking discoveries over the centuries. While photovoltaic cells have become a mainstream solution for harnessing solar energy, the concept of converting light into electricity began long before modern solar panels were developed.

Early Discoveries Leading to Photovoltaics

The concept of light being able to generate electricity was first explored in the 19th century. Two early discoveries laid the foundation for photovoltaic technology: the photoelectric effect and the discovery of the properties of semiconductors.

Antoine-César Becquerel and the Photoelectric Effect (1839)

The first major breakthrough in the development of photovoltaic technology occurred in 1839 when French physicist Antoine-César Becquerel discovered the photoelectric effect. Becquerel was studying how certain materials produce an electric current when exposed to light. He found that when light hit a surface of platinum in an electrolytic cell, it created a tiny electric current. This phenomenon was later understood as the photoelectric effect—the process where light causes electrons to be ejected from a material, creating a flow of electricity.

While Becquerel’s discovery was not yet directly applicable to solar power, it set the stage for future research into harnessing light as an energy source.

Albert Einstein and the Nobel Prize (1905)

Fast forward to 1905, when Albert Einstein published a paper explaining the photoelectric effect in more detail. He proposed that light is made up of particles called photons and that when photons collide with atoms, they can release electrons from their orbits, generating an electric current. This was a significant theoretical advancement, and it earned Einstein the Nobel Prize in Physics in 1921.

Einstein’s explanation of the photoelectric effect proved that light could be harnessed to produce electricity. This laid the theoretical groundwork for the development of photovoltaic technology and solar cells.

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The Development of the First Solar Cell

The theoretical foundations were in place, but practical implementation of photovoltaic cells took several more decades. The next major step toward creating functional solar cells occurred in the late 19th and early 20th centuries.

Charles Fritts and the First Solar Cell (1883)

In 1883, Charles Fritts, an American inventor, created the first working solar cell by coating a thin layer of selenium with a thin layer of gold. Selenium, a semiconductor, was chosen because of its ability to generate electricity when exposed to light. Although Fritts’ solar cell was highly inefficient (only about 1% efficiency), it marked the first successful attempt at converting sunlight directly into electricity.

Though rudimentary by today’s standards, Fritts’ work was groundbreaking. It demonstrated that it was possible to generate electricity from sunlight, paving the way for future developments in solar technology.

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The Birth of Modern Photovoltaic Technology

The real leap into modern photovoltaic technology began in the mid-20th century, when researchers developed more efficient materials and refined the technology that would eventually lead to the solar panels we know today.

Bell Labs and the First Silicon Solar Cell (1954)

The first practical solar cell that could generate enough power for commercial use was developed in 1954 at Bell Labs in Murray Hill, New Jersey. The researchers Daryl Chapin, Calvin Fuller, and Gerald Pearson are credited with creating the first silicon-based solar cell, which was much more efficient than previous models. This new silicon solar cell had an efficiency of about 6%, a significant improvement over earlier designs.

This breakthrough in 1954 is often cited as the true “birth” of modern photovoltaic technology. The efficiency of the silicon solar cell, combined with its ability to scale for larger applications, made it possible to use solar power for real-world applications, including powering satellites in space.

The Space Age and the Use of Solar Panels

The 1950s and 1960s marked the dawn of space exploration, and photovoltaic technology found an immediate application in powering satellites. Since traditional power sources were impractical for space missions, solar panels became the go-to solution to keep satellites powered while orbiting the Earth.

This period also saw the first commercial use of photovoltaic systems, albeit at a high cost. Solar cells began to power remote locations and devices like water pumps in areas where conventional electricity wasn’t accessible.

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The 1970s Energy Crisis and the Growth of Solar Energy

While photovoltaic technology had made significant strides, it was the 1970s energy crisis that truly sparked widespread interest in solar power. As oil prices soared and concerns over energy independence grew, governments and private industries began to take renewable energy seriously.

The Push for Solar Research and Development

During the 1970s, various governments, particularly in the United States, began investing heavily in renewable energy. As part of these efforts, significant funding was directed toward solar research and development, which helped bring down the cost of photovoltaic technology and increase its efficiency.

This investment led to rapid advancements in solar technology, including improvements in solar cell efficiency and the development of cheaper production methods. By the end of the decade, solar power had gained momentum as a viable alternative energy source.

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• Antoine-César Becquerel‘s discovery of the photoelectric effect in 1839 was a foundational moment for solar power.
• Albert Einstein’s explanation of the photoelectric effect in 1905 provided the theoretical underpinnings for photovoltaic technology.
• Charles Fritts created the first working solar cell in 1883 using selenium, but it had very low efficiency.
• The first modern silicon solar cell was developed by Daryl Chapin, Calvin Fuller, and Gerald Pearson at Bell Labs in 1954, making practical solar energy a reality.
• The 1970s energy crisis spurred further development of solar power, leading to increased investments in renewable energy technologies.

Who Is the Founder of Photovoltaic? Unpacking the Contributions of Key Pioneers

When we ask, “Who is the founder of photovoltaic?”, it’s important to recognize that the development of photovoltaic technology was not the work of a single person, but rather a collective effort by many scientists, inventors, and researchers over several centuries. Photovoltaic technology, as we know it today, is the result of a series of discoveries, breakthroughs, and advancements, each building on the previous one.

While some might assume there is one clear founder, the truth is more nuanced. Various contributors laid the groundwork for modern solar power, and each played a vital role in advancing the technology. Let’s take a look at the key figures who contributed significantly to the creation and evolution of photovoltaic technology.

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Key Figures in the History of Photovoltaic Technology

1. Antoine-César Becquerel (1839)

The journey toward photovoltaic technology began in the 19th century with Antoine-César Becquerel, a French physicist. As mentioned earlier, Becquerel’s discovery of the photoelectric effect in 1839 was one of the first steps in understanding how light could be used to generate electricity.

While Becquerel didn’t invent the solar cell, his work demonstrated that light could release electrons in a material, generating a flow of electricity. His discovery set the stage for later research into how to harness this effect to produce practical energy.

2. Charles Fritts (1883)

A major leap forward in the development of photovoltaic technology came with Charles Fritts, an American inventor who created the first working solar cell in 1883. Fritts coated a thin layer of selenium with gold, and when exposed to light, this combination generated an electric current.

Though the efficiency of his solar cell was very low (about 1%), Fritts’ solar cell was the first to convert light directly into electricity, marking an important milestone in the history of photovoltaic technology.

Fritts is often credited with inventing the first solar cell, but due to the technology’s limited effectiveness at the time, it didn’t have immediate practical applications.

3. Albert Einstein (1905)

Although Einstein’s groundbreaking work wasn’t directly focused on the development of solar cells, his explanation of the photoelectric effect in 1905 was crucial in understanding how light interacts with materials to release electrons.

Einstein’s theoretical work explained that light is composed of particles called photons, and when these photons hit a material, they could knock electrons loose, generating an electric current. This explanation was pivotal because it helped scientists understand how photovoltaic cells could work at a fundamental level. Einstein’s contributions earned him the Nobel Prize in Physics in 1921, and his theories still underlie the principles of modern photovoltaic technology.

4. Daryl Chapin, Calvin Fuller, and Gerald Pearson (1954)

The next major breakthrough came in 1954, when Daryl Chapin, Calvin Fuller, and Gerald Pearson, researchers at Bell Labs in New Jersey, created the first efficient silicon solar cell.

This solar cell, made from silicon, was a significant improvement over earlier designs. It had an efficiency of around 6%, which was a huge leap compared to previous cells that barely generated any usable electricity. The creation of the silicon solar cell was a turning point because it made solar energy practical for real-world applications, including powering satellites in space.

This development by Chapin, Fuller, and Pearson is considered the birth of modern photovoltaic technology. Their work is regarded as one of the most significant milestones in the field, and they are often credited with creating the foundation for all subsequent solar technologies.

5. Modern-Day Innovators and Entrepreneurs

While the initial development of photovoltaic technology can be traced to these early pioneers, the field has continued to evolve rapidly, thanks to ongoing research, innovation, and commercialization.

• M. A. Green: Professor Martin Green from the University of New South Wales in Australia has made numerous contributions to improving the efficiency of solar cells. His work on the perovskite solar cells and multi-junction solar cells has pushed solar technology to new heights of performance and efficiency.
• Elon Musk: Through his companies Tesla and SolarCity, Elon Musk has been a driving force in popularizing solar energy and reducing the cost of solar systems. Tesla’s solar roof and SolarCity’s residential solar panels have made it easier for individuals and businesses to access solar energy.
• First Solar and SunPower: Companies like First Solar and SunPower have been major players in developing large-scale photovoltaic systems and driving down the costs of solar energy. Their innovative work has helped expand solar energy into a mainstream source of power for utility-scale plants and communities.

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Why Is There No Single “Founder” of Photovoltaic Technology?

While some people may want to point to a single individual as the “founder” of photovoltaic technology, the reality is that photovoltaic energy is the result of cumulative discoveries and collaborative efforts over many decades. Each key figure contributed a unique discovery or advancement that, when combined, has led to the technology we use today.

• Becquerel’s discovery laid the theoretical groundwork by demonstrating that light could generate electricity.
• Fritts’ first solar cell showed that solar cells could convert light into usable energy, even if it was inefficient at the time.
• Einstein’s explanation of the photoelectric effect provided the theoretical understanding of how photons could be harnessed to release electrons.
• The 1954 breakthrough by Chapin, Fuller, and Pearson created the first viable solar cell, making photovoltaic technology a practical solution.

In short, there is no single founder—instead, photovoltaic technology is the result of a community of innovators who built upon each other’s work over time.

How Did Photovoltaic Technology Evolve Over Time?

Photovoltaic (PV) technology has undergone incredible advancements since its inception. While early solar cells were inefficient and expensive, over time, breakthroughs in materials science, manufacturing techniques, and technological innovations have made photovoltaic systems more practical and cost-effective.

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Early Limitations and Advancements

In the early stages of photovoltaic technology, the primary challenge was efficiency. The first solar cells, such as those created by Charles Fritts in 1883, had very low energy conversion rates—often less than 1%. The main reasons for this were:

• Material Limitations: The materials used, such as selenium, were not optimal for generating electricity from sunlight. While they could produce a small amount of electricity, their efficiency was far from practical for large-scale energy generation.
• Manufacturing Constraints: The production of early solar cells was labor-intensive and expensive, limiting their adoption to niche applications like remote telecommunication systems or space missions.

However, as research continued through the mid-20th century, scientists began to explore more effective materials, particularly silicon, which would later become the foundation for modern solar cells.

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The Development of Silicon-Based Solar Cells (1950s-1960s)

The real breakthrough in photovoltaic technology came in the 1950s when researchers discovered that silicon, a semiconductor material, could be used to manufacture highly efficient solar cells. Silicon has excellent electrical properties, making it ideal for harnessing energy from the sun.

Bell Labs’ Breakthrough (1954)

The 1954 development of the silicon solar cell by Daryl Chapin, Calvin Fuller, and Gerald Pearson at Bell Labs marked the beginning of practical solar energy systems. The silicon solar cell had an efficiency of about 6%, which was a significant leap from the previous selenium-based solar cells. While this efficiency was still relatively low, it was a viable option for applications in space and remote energy generation.

The Space Race and Early Applications in Space (1950s-1960s)

The advent of silicon-based solar cells coincided with the Space Race during the Cold War. Satellites and spacecraft required compact and reliable power sources, making solar panels a natural solution. Early solar panels were used to power spacecraft like the Vanguard 1 (1958) and Telstar 1 (1962), the first communication satellite.

Solar cells were used because they were lightweight, durable, and could continuously generate power when exposed to sunlight, which made them ideal for space missions. This marked the first large-scale use of photovoltaic technology, and it demonstrated that solar power could be relied upon for high-demand applications.

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The 1970s Energy Crisis and Solar Energy Growth

The 1970s energy crisis was a pivotal moment in the development of solar energy. A combination of geopolitical factors—particularly the Arab Oil Embargo and oil price hikes—led to widespread concerns about energy security and dependence on fossil fuels. As a result, both governments and the private sector began to invest heavily in alternative energy sources, including solar power.

Increased Research and Government Incentives

The energy crisis of the 1970s led to increased funding for solar energy research. The U.S. Department of Energy (DOE) launched programs to support solar research, resulting in advancements in photovoltaic technology. The Solar Energy Research Institute (SERI) was founded in 1977 to lead solar research and development.

Simultaneously, several government incentives and subsidies were introduced to make solar energy more accessible to the public. These incentives included tax credits, research grants, and programs aimed at reducing the cost of solar systems. The National Renewable Energy Laboratory (NREL), established in the 1970s, played a key role in advancing solar cell technologies and improving the efficiency of PV systems.

Cost Reduction and Efficiency Improvements

In the 1970s and 1980s, the efficiency of solar cells began to rise due to significant advancements in materials and manufacturing techniques. Researchers focused on improving the efficiency of silicon solar cells and developing alternative materials to lower production costs.

By the late 1980s, multi-crystalline and polycrystalline silicon cells began to emerge. These cells were less expensive to manufacture than single-crystal silicon cells and still offered significant improvements in efficiency, making them suitable for wider use in residential and commercial solar installations.

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Technological Breakthroughs and Innovation (1990s-2000s)

By the 1990s, the photovoltaic industry had begun to gain traction. The combination of improving solar cell efficiency, decreasing production costs, and growing environmental concerns led to an acceleration in the adoption of solar energy. Several technological breakthroughs during this period were key to the industry’s growth.

Thin-Film Solar Cells

One significant breakthrough in the 1990s was the development of thin-film solar cells. These cells use very thin layers of semiconductor materials, such as cadmium telluride (CdTe) or copper indium gallium selenide (CIGS), instead of traditional silicon. Thin-film technology is cheaper to produce and can be applied to a wider range of surfaces, including windows, rooftops, and even clothing. While thin-film cells were initially less efficient than silicon-based solar cells, their lower production cost and flexibility led to their adoption in certain market segments.

Concentration Photovoltaics (CPV)

Another innovation in the 1990s was the development of concentrator photovoltaics (CPV). CPV uses lenses or mirrors to focus sunlight onto small, highly efficient solar cells. This approach allows for higher energy production per unit of area, although it requires precise tracking systems to follow the sun’s movement throughout the day.

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The 2000s to Present: Mainstream Adoption and Efficiency Improvements

The 2000s saw the rapid growth of solar power, driven by both technological advancements and market forces.

Declining Costs and Global Expansion

One of the most significant developments in the 21st century was the dramatic decline in solar panel costs. As demand for solar energy grew, manufacturers were able to take advantage of economies of scale, resulting in lower prices for solar panels. The cost of solar energy systems dropped by over 80% from 2008 to 2018, making solar energy increasingly affordable for both residential and commercial customers.

This decrease in cost, combined with government incentives and rising energy demand, contributed to the global expansion of solar power. Countries like Germany, China, and the United States led the way in solar adoption, investing in large-scale solar power plants and offering incentives for rooftop installations.

Efficiency Improvements and Emerging Technologies

Today, solar cells are far more efficient than they were in the past. The best-performing silicon solar cells now exceed 20% efficiency, and high-efficiency cells like multi-junction solar cells can reach efficiencies of over 40%. Moreover, new materials such as perovskite are showing great promise, with potential efficiencies approaching 30% at much lower production costs.

Researchers are also exploring the use of organic photovoltaics (OPVs) and quantum dot solar cells as next-generation alternatives to silicon. These technologies could potentially reduce costs further and offer more versatile applications for solar power in the future.