What Are Transparent Solar Panels, and How Do They Work?

In 2024, researchers at Incheon National University shared the results of an exciting study. 

A team of academics in the university’s Department of Electrical Engineering wanted to learn more about the real-world applicability of transparent solar panels: an idea that had been in development for over ten years. 

The investigation, which culminated in the following research paper, found that the department’s fabricated transparent photovoltaic cells (TPCs) showed evidence of UV signal sensitivity, high responsivity and fast response time. 

These are all positive indicators that TPCs are, indeed, invisible power generators! However, this is by no means the first study of its kind. Scientists in Germany, Japan and China are all looking for ways to make this technology more efficient. 

Learn more about transparent solar panel technology with Project Solar. 

Definition of transparent solar panels 

Transparent solar panels aren’t a relatively new concept. In fact, researchers at Michigan State University were the first to develop these PV systems back in 2014. 

Also called a ‘transparent luminescent solar concentrator,’ this type of solar panel uses small organic molecules to absorb specific non-visible wavelengths of sunlight.

According to Richard Lunt, the university’s assistant professor of chemical engineering, the infrared light is then guided to the edge of the plastic, where it is converted to electricity by thin strips of photovoltaic solar cells. 

But how do these panels get their ‘transparent’ look? As the materials don’t absorb or emit light in the visible spectrum, they look transparent to the human eye. 

The title of the study, ‘Solar energy that doesn’t block the view’, refers to the potential usefulness of these panels in densely populated areas where installing traditional panels may not be possible. 

Rather than being installed solely on rooftops, as is the typical method, transparent panels could be used in buildings, window panes, and even touchscreens. 

What are the different types of transparent panels? 

There are multiple types of transparent panels, some entirely clear and others ‘semi-transparent’. These panels differ in how much visible light they allow through and how much energy they generate.

• Partially transparent panels 

Partially transparent solar panels allow some visible light to pass through; these systems are ideal for applications like building windows. 

Semi-transparent panels often incorporate thin-film technologies such as amorphous silicon or perovskites, which offer flexibility but generally lower efficiency compared to traditional silicon-based panels.

For example, German manufacturers have developed a partially transparent panel that achieves around 60% transparency, with an efficiency rate of 7.2%. 

• Fully transparent panels 

Fully transparent solar panels, on the other hand, aim to let all visible light through. 

As they appear to be ordinary glass, their potential lies in widespread applications such as glass skyscrapers, where the sheer scale of glass surfaces could compensate for their lower efficiencies (1-5%). 

Advancements in material science, such as the development of more efficient perovskite-based transparent cells, could eventually significantly boost their energy conversion potential.

How could transparent solar cells be used? 

Transparent solar panels present a groundbreaking opportunity for integrating renewable energy into a wide variety of settings. 

Unlike traditional solar panels, which are often limited to rooftops or ground installations, transparent solar cells can be applied in multiple contexts, from buildings to aerospace technology: 

• Building-Integrated Photovoltaics (BIPV)

Transparent solar cells are ideal for Building-Integrated Photovoltaics (BIPV). These panels can be incorporated directly into windows, skylights, and facades of buildings without altering their appearance. 

BIPV systems could help buildings achieve net-zero or even positive energy generation, especially when combined with other energy efficiency measures. 

• Aerospace 

These panels’ lightweight and transparent nature makes them well-suited for aerospace applications, particularly in satellites or spacecraft. By providing power without adding significant weight, they could capture infrared and ultraviolet light. 

• Public spaces and infrastructure

Transparent solar cells could transform public spaces by integrating into bus stops, walkways, and shelters. These panels could generate power for lighting and digital displays without being visually distracting. 

In cities like London, where space is at a premium, using transparent surfaces for energy generation offers an innovative way to increase solar adoption without the need for additional land. 

• Greenhouses

Transparent panels could also benefit the agricultural sector. When installed on greenhouse roofs, they could generate electricity while still allowing sufficient sunlight to pass through to promote plant growth.

Recent advancements in semi-transparent solar technology have demonstrated efficiencies of around 3-4%, which would make them capable of supporting energy needs like temperature regulation systems and sensors. 

Traditional PV panels Vs. Clear solar panels

Traditional solar panels and clear PV systems are two drastically different technologies, which means they also have different applications. 

Traditional panels are opaque, designed to capture the full spectrum of sunlight, including visible light, which they convert into electricity with high efficiency (efficiencies differ depending on whether they are polycrystalline, monocrystalline, or bifacial panels). 

Transparent solar panels, however, are designed to allow visible light to pass through and capture only ultraviolet (UV) and infrared (IR) light. However, this transparency comes at the cost of lower efficiency, depending on whether they are fully or partially transparent.

What are the advantages of transparent solar panels? 

• Aesthetic integration: Transparent panels can be integrated into windows, skylights, and building facades without affecting the appearance of the structure.
• Dual functionality: In addition to power generation, transparent panels can serve as architectural elements. They can be used in glass surfaces to reduce solar heat gain in buildings, cutting down on cooling costs. 
• Broader applications: Transparent solar cells can be used in areas where traditional panels are impractical, such as car windows, mobile devices, and even greenhouses. 
• Potential for widespread adoption: With billions of square metres of glass surfaces in buildings globally, transparent panels offer vast untapped potential to generate solar power without taking up additional space. 

What are the advantages of traditional PV panels? 

• Higher efficiency: Traditional solar panels are far more efficient, with much higher energy conversion rates. They’re much more suited for high-energy demand applications like residential power or large solar farms​. 
• Proven technology: Traditional PV technology has been around for decades. It’s a reliable, cost-effective option with well-understood performance metrics. It’s also scalable and widely adopted in both residential and industrial settings. 
• Cost-effectiveness: Due to economies of scale, traditional solar panels are cheaper to manufacture and install. Their higher efficiency means fewer panels are required to generate a significant amount of electricity. 

Contact Project Solar for domestic installations around the UK!

While it may be some time before transparent solar panels are commercially available, scientists around the world are working hard to harness their potential. In the meantime, why not get your foot on the green ladder with Project Solar’s solar panels? 

Available for both domestic and commercial properties, our high-tech solar panels can supplement your grid-generated energy. Contact us today to learn more.