What are Copper Indium Gallium Selenide Solar Cells? Definition, Advantages & Disadvantages

Copper Indium Gallium Selenide (CIGS) solar cells represent an emerging thin-film photovoltaic technology with demonstrated world-record conversion efficiency rates rivaling mainstream silicon cells.

As a semiconductor composed of copper (Cu), indium (In), gallium (Ga), and selenium (Se), CIGS leverages unique solar spectrum absorption properties that increase thin-film solar panel efficiency beyond the typical rates. Copper indium gallium selenide solar cells work through the photovoltaic effect, where sunlight produces an electric current upon contact with a semiconductor material. CIGS thin-film cells are structured with an absorption layer made of the CIGS semiconductor materials sandwiched between the front and back electrode layers.

When it comes to their efficiency, copper indium gallium selenide (CIGS) cells have proven to be an effective semiconductor material for solar panels. While still a relatively new technology compared to silicon solar cells, CIGS thin-film cells have demonstrated excellent efficiency rates as high as 23.35% in lab tests, rivaling traditional silicon cell-types like monocrystalline and multicrystalline.

There are several benefits of Copper Indium Gallium Selenide (CIGS) solar cells that make them an attractive option for solar power generation. These include their high efficiency and reliable performance in low-light conditions.

CIGS solar panels rely on scarce raw metals like indium and gallium for production, which drive prices higher than silicon. However, ongoing manufacturing innovations aim to substantially trim costs in the coming years. Given its balance of efficiency, sustainability, and stability, CIGS has the potential to claim significant market share in the coming years, provided that production scales successfully.

What is Copper Indium Gallium Selenide?

Copper indium gallium selenide (CIGS) is an I-III-VI semiconductor used to produce thin-film solar cells, one of the three main types of solar cells. Composed of copper (Cu), indium (In), gallium (Ga), and selenium (Se), CIGS has a chemical formula of CuIn1−xGaxSe2, where the value of x can vary from 0 (pure copper indium selenide) to 1 (pure copper gallium selenide).

As a semiconductor, CIGS has photovoltaic properties, meaning it converts sunlight directly into electricity. The exact semiconductor properties change depending on the ratios of copper, indium, gallium, and selenium used, allowing manufacturers to optimize efficiency. This changing efficiency is evident in CIGS thin-film solar panels, which currently reach efficiency rates as high as 23.35%. CIGS is one of the main thin-film solar cell types used to convert sunlight into electricity. These efficiency levels were achieved by Nakamura et al. in 2019 for CIGS solar cells. CIGS flexible solar panel modules feature a recorded efficiency of 22.2%. This was achieved in 2022 by the Swiss Federal Laboratories for Materials Science & Technology (EMPA).

Compared to other thin-film solar technologies, CIGS panels perform better in smaller spaces and low-light conditions. Their thin-film structure makes CIGS more flexible than traditional silicon cells. However, CIGS tends to be more expensive due to reliance on rare materials like indium and gallium. Overall, CIGS presents a promising alternative solar panel material with competitive efficiency.

What is Copper Indium Gallium Selenide Made of?

Copper Indium Gallium Selenide (CIGS) solar cells are made of an I-III-VI semiconductor material composed of four primary elements, which are copper (Cu), indium (In), gallium (Ga), and selenium (Se). The specific ratio of these materials gives CIGS its unique semiconductor properties. An I-III-VI semiconductor is a type of compound semiconductor made from elements in groups I, III, and VI of the periodic table. CIGS is one of the most common examples of an I-III-VI semiconductor and is commonly found in thin-film solar panels.

The ratios of the components used within CIGS cells change depending on the manufacturing process, but copper typically makes up at least 20-30%. The copper present in CIGS contributes to electrical conductivity and current collection properties. Indium comprises around 13-16% of the makeup of CIGS and largely determines the solar conversion efficiency rates.

Gallium usually makes up 2-10% of CIGS, boosting resistance to heat and light-induced performance degradation. Finally, selenium makes up the remaining 40-60% of the CIGS as the primary absorber of light particles.

The exact percentages of these four materials are able to be adjusted to optimize efficiency depending on the manufacturing and applications. But in general, the combination of copper, indium, gallium, and selenium gives CIGS solar cells advantageous efficiency and stability over other thin-film technologies.

How does Copper Indium Gallium Selenide Work?

Copper indium gallium selenide solar cells work through the photovoltaic effect, which is the process of converting sunlight directly into electricity. Specifically, CIGS thin-film cells are structured with an absorption layer made of the CIGS semiconductor material sandwiched between front and back electrode layers.

When sunlight hits a CIGS solar cell, photons are absorbed by the CIGS layer, transferring their energy to the electrons in the copper, indium, gallium, and selenium atoms. This extra energy frees the electrons from the atom, allowing the electrons to flow through the CIGS layer to the front electrode. The electron flow generates an electrical current, harnessing power from the solar photons.

The CIGS layer's semiconductor properties are able to be optimized to enable efficient photon absorption and electron mobility to maximize current flow. Meanwhile, the front and back electrode layers collect the current. By exposing CIGS solar cells to sunlight and connecting the electrodes to an external load, the electrons move to power the load before returning to the back layer, completing an electric circuit.

Fine-tuning the structure and ratio of materials in CIGS allows solar panel manufacturers to raise efficiency rates. The thin-film flexibility enables integration into more applications compared to rigid silicon cells. These advantages make CIGS a uniquely versatile and competitive solar technology.

Is Copper Indium Gallium Selenide Effective for Solar Panels?

Yes, copper indium gallium selenide (CIGS) has proven to be an effective semiconductor material for solar panels. While still a relatively new technology compared to silicon solar cells, CIGS thin-film cells have demonstrated excellent efficiency rates as high as 23.35% in lab tests. This rivals multicrystalline silicon solar cells (around 13-16% efficiency) in significantly less surface area.

In real-world applications by solar companies like MiaSolé, CIGS modules reliably reach 15-17% efficiency ratings. That effectiveness makes CIGS a viable alternative to rooftop solar panels and flexible mobile chargers.

One key advantage of CIGS solar panels is that their effectiveness degrades slower than silicon in hot climates. CIGS absorbs energy evenly across the light spectrum, collecting more low-light photons. Its thin-film structure also utilizes materials efficiently, with 1/100th the thickness of silicon needed for comparable electric output.

While the higher cost per watt of CIGS solar currently limits massive-scale manufacturing, advancing production techniques and more affordable material sourcing has the potential to enable CIGS to challenge silicon photovoltaic dominance. In short, the existing efficiency and stability metrics prove CIGS is already effective for solar, with ample room for improvement to become more cost-competitive.

What are the benefits of using Copper Indium Gallium Selenide Solar Cells?

Copper Indium Gallium Selenide (CIGS) solar cells have several benefits that make them an attractive option for solar power generation. The six key benefits of using CIGS solar cells are high efficiency, space-saving, performance in low light, temperature resilience, cost-effectiveness, and versatility.

More information about the 6 key benefits of using CIGS solar cells is below:

• High Efficiency: CIGS solar cells are efficient thin-film solar cells, usually within a range of 12-22% efficiency. Under lab conditions, some CIGS solar cell prototypes have achieved up to 23-24% efficiency, comparable with monocrystalline panels. The high efficiency of CIGS cells is due to the direct-bandgap material’s ability to absorb a significant portion of the solar spectrum. Direct band-gap materials are a type of semiconductor material in which the minimum energy required for an electron to move from the valence band to the conduction band occurs at the same value of momentum.
• Space Savings: The thin-film structure of CIGS cells allows for high energy yields with a slim profile. Solar manufacturers are able to produce more watts per square meter using CIGS compared to bulkier silicon cells using the same rooftop or surface area.
• Performance in Low Light: CIGS performs better than silicon at lower light levels, including under cloud cover and early morning/evening times. This enables energy collection across more varying light conditions.
• Temperature Resilience: Tests show minimal loss of efficiency for CIGS even in hotter temperatures that degrade silicon cell performance. This bodes well for CIGS resilience over decades of outdoor exposure.
• Cost-Effectiveness: For a production capacity of 1000 MW y−1 with 15% module efficiency, the CIGS module production cost is expected to be $0.34 W −11. This makes CIGS solar cells a cost-effective alternative to traditional silicon solar cells.
• Versatility: CIGS is a versatile material that can be fabricated by multiple processes and implemented in different form factors. For example, CIGS can be deposited on substrates such as glass, metal foils, and polymers. This allows for applications that require lighter-weight or flexible modules.

What are the Advantages and Disadvantages of Using Copper Indium Gallium Selenide Solar Cells?

The advantages and disadvantages of CIGS cells are outlined below.

Advantages

• Flexible: CIGS solar cells can be deposited on substrates such as glass, metal foils, and polymers. This is because the thin-film structure of the CIGS module makes it flexible and lightweight, enabling unique shapes and applications.
• Heat Resistance: CIGS efficiency is less impacted by high heat compared to silicon cells. This improves their long-term performance. More so, CIGS solar cells have a high absorption coefficient and strongly absorb sunlight. This makes them resistant to heat and suitable for various environmental conditions.
• Contain Non-Toxic Materials: CIGS solar modules are made of non-toxic materials. Therefore, they are environmentally friendly.

Disadvantages

• Low Efficiency: While CIGS solar cells have achieved 22.8% efficiency, which is comparable to crystalline silicon (c-Si) wafer-based solar cells, their module efficiency is still lower. This is due to a less mature upscaling.
• Not Competitive: According to the Photovoltaic report by Fraunhofer ISE, the market share of CIGS alone was about 2 percent in 2013, and that of all other thin-film technologies combined fell below 10 percent. This indicates that CIGS solar cells are not yet competitive with other solar cell technologies.
• Limited Production Capacity: For a production capacity of 1000 MW y−1 with 15% module efficiency, the CIGS module production cost is expected to be $0.34 W −13. However, due to process complexity, CIGS module production is lagging behind that of cadmium telluride (CdTe) modules.

While there are several advantages of CIGS solar modules, there are also disadvantages which when addressed, will make them more competitive in the solar power market.

How Efficient Is Copper Indium Gallium Selenide Solar Cell?

Copper Indium Gallium Selenide (CIGS) solar cells are thin-film solar cells that achieve an exceptionally high efficiency rate for converting sunlight to electrical energy. Under optimized lab testing conditions, CIGS cells have achieved efficiency levels as high as 23.35%, which rivals the peak rates for mainstream crystalline silicon solar panels.

Commercially available CIGS solar panels designed for real-world conditions reliably reach 15% to 18% efficiency levels. The consistency of these competitive conversion rates is a major reason CIGS technology presents a viable alternative to silicon photovoltaics. For comparison, mass-market multicrystalline silicon solar panels operate at around 9-14% efficiency.

CIGS thin-film layers absorb energy evenly across the solar spectrum, utilizing more of the sun's photons more effectively than silicon semiconductors. The flexibility to fine-tune the ratio of copper, indium, gallium, and selenium for CIGS panels provides room for improvements in the efficiency level. Going forward, enhanced manufacturing techniques could unlock even higher stable efficiency rates for CIGS solar panels, if production scales.

How much is the Average Price of Copper Indium Gallium Selenide Solar Cells?

The average price of copper indium gallium selenide (CIGS) solar cells is currently around $0.30 to $1.25 per watt, according to market research estimates. However, the price of Copper Indium Gallium Selenide (CIGS) solar cells varies based on several factors, including the efficiency of the cells, and the specific manufacturer.

Furthermore, the CIGS solar cell market is projected to grow at a Compound Annual Growth Rate (CAGR) of 7.78% and reach USD 4,170.00 million by 2029. This projection suggests that the average price of CIGS solar cells is likely to decrease as the technology matures and production scales up. Factors such as efficiency, production costs, and market demand further affect the average cost of CIGS solar cells.

Are Copper Indium Gallium Selenide Solar Cells Effective for High Solar Energy Production?

Yes, Copper Indium Gallium Selenide (CIGS) solar cells are effective for higher solar energy production. While CIGS currently comprises a small single-digit percentage of solar capacity installed globally, the technology presents excellent potential to scale as a major source of renewable energy.

Real-world solar farms and rooftop solar arrays using CIGS modules generate reliable, clean power outputs on par with mainstream silicon photovoltaics. Extensive durability testing indicates minimal degradation of CIGS cell efficiency over time, ensuring sustained performance over decades.

The record 23.35% cell efficiency achieved by some CIGS panels k, along with impending cost improvements thanks to scaled manufacturing, provides headroom to extract even more solar energy per module. While still early in maturity compared to silicon and thin-film technologies like CdTe, CIGS has the potential to be more effective for high solar energy production in the future.

Is Copper Indium Gallium Selenide Solar Cell Better than Amorphous Silicon?

Yes, copper indium gallium selenide (CIGS) solar cells perform better overall than amorphous silicon cells. This is because thin-film modules, such as CIGS, are emerging in the photovoltaic market due to their competitive cost compared to traditional crystalline silicon modules. CIGS cells are predominating due to their low-temperature coefficient and the ability to absorb ultraviolet (UV) and infrared (IR) light.

While amorphous silicon benefited from the early optimism amongst players in the photovoltaic market, real-world limitations have capped their practical usage. In contrast, CIGS offers competitive efficiency with more resilient outdoor durability.

In lab testing, CIGS cells achieve substantially higher efficiency rates, reaching over 23% compared to amorphous silicon's ceiling of around 11%. When it comes to commercial production, CIGS modules operate between 15-18% efficiency. Amorphous silicon peaks at 9% efficiency in mass-production applications. That major performance gap makes CIGS the clear winner between CIGS and Amorphous Silicon per unit of panel surface area.

When first exposed outdoors, amorphous silicon suffers up to 50% efficiency losses from initial light-induced degradation. By comparison, CIGS shows superior stability with minimal efficiency losses over decades in the field. So, while amorphous silicon provided early optimism, CIGS solar technology has surpassed expectations with better performance metrics that matter.

Is Copper Indium Gallium Selenide Solar Cell Better than Cadmium Telluride?

Yes, copper indium gallium selenide (CIGS) solar cells are better than cadmium telluride (CdTe) solar cells. While both are leading thin-film technologies, CIGS offers higher efficiency potential and fewer environmental concerns.

In lab testing under concentrated sunlight, CIGS cells have achieved a world record efficiency of 23.35%, edging out CdTe's maximum of 22.1%. Commercially available CIGS modules potentially reach 15-18% efficiency, on par with top-end CdTe products. CIGS maintains better solar conversion stability in the long term.

The key advantage for CIGS is utilizing more benign raw materials without toxic cadmium risks. Cadmium Telluride (CdTe) cells require stringent manufacturing and disposal protocols to limit exposure. While processes are regulated, CIGS provides inherent environmental benefits for large-scale solar adoption.

Overall, CIGS solar technology provides competitive or superior performance metrics compared to CdTe cells while avoiding the element's toxicity concerns. These factors give CIGS an edge as the thin-film photovoltaic sector grows rapidly.

Is Copper Indium Gallium Selenide the same as Copper Indium Gallium Diselenide?

No, copper indium gallium selenide (CIGS) and copper indium gallium diselenide (CIGS2) are not the same. While their names and chemical formulas appear similar, each material has its own distinct structures and solar cell properties.

The key difference between CIGS and CIGs2 lies in the selenium content. CIGS contains one selenium atom for each atom of copper, indium, and gallium. This equimolar ratio is crucial for forming the chalcopyrite crystal semiconductor structure that has the potential to enable high-efficiency solar energy conversion in CIGS cells.

Meanwhile, CIGS(2) doubles the selenium ratio with two selenium atoms fitting into the crystal lattice for each metal atom. The resulting structure in CIGS(2) does not absorb and convert sunlight as effectively as CIGS. Testing shows that CIGS(2) is topping out at around 5% solar cell efficiency, far below the 23% record for CIGS materials.

So, in short, the defining balance of selenium determines the properties. While combinations of copper, indium, and gallium hold solar promise, only CIGS, with its single selenium ratio, has emerged as a leading thin-film photovoltaic technology thus far. The extra selenium makes CIGS(2) a distinctly different material.

Which is more Efficient Between Copper Indium Gallium Selenide and Gallium Arsenide?

Copper Indium Gallium Selenide (CIGS) solar cells are more efficient than Gallium Arsenide (GaAs), under lab conditions. CIGS holds the overall efficiency world record for solar cells at 23-24%, compared to 25.1% for the best GaAs cell.

However, the highest confirmed gallium arsenide efficiency rates have the potential to surpass current commercially available CIGS modules. Top-end gallium arsenide production cells operate at around 30% efficiency. Mass-produced CIGS solar panels range between 15-18% real-world efficiency.

The key difference between CIGS and GaAs lies in their manufacturing methods. Gallium arsenide (GaAs) cells utilize expensive crystalline production perfected over decades to achieve peak physics conversion. CIGS relies on thinner and cheaper films with tradeoffs compensated by light-spectrum advantages.