Understanding Cadmium Telluride (CdTe) Solar Cells

The U.S. Department of Energy (DOE) Solar Energy Technologies Office (SETO) actively supports pioneering research aimed at addressing the technological and commercial challenges associated with cadmium telluride (CdTe) solar modules. This article outlines the manufacturing process of a CdTe solar module, recent advancements in cell design, and the benefits linked to this technology. You can find more information on our website, so please explore it.

What is a CdTe Solar Cell?

Cadmium Telluride, commonly referred to as CdTe, consists of a combination of two elements: Cadmium (Cd) and Tellurium (Te). This material is essential for light absorption, which is why the solar cell bears its name. However, other components are necessary for the solar cell to operate effectively.

As a type of thin-film technology, CdTe utilizes a thin layer that absorbs light, generating excited charged particles known as electrons. The movement of these electrons is what creates an electric current. CdTe solar cells are categorized as thin-film due to their superior absorptive qualities compared to silicon solar cells, enabling them to achieve similar light absorption with thinner layers.

Within the solar cell, the CdTe absorber connects to various materials that facilitate the flow of electric current through the absorber layer to metal contacts, enabling the generation of sustainable electricity. In contemporary designs, cadmium selenium tellurium (CdSeTe) is often used alongside CdTe to enhance light absorption. Find out more about how solar cells function.

CdTe solar cells rank second only to crystalline silicon in prevalent photovoltaic (PV) technologies, accounting for 21% of the U.S. market and 4% of the global market in recent years. Over the past 15 years, the deployment of CdTe has escalated from megawatt to gigawatt scale, with module efficiency more than doubling.

Benefits and Challenges of Cadmium Telluride

Cadmium Telluride: The Pros and Cons

Cadmium Telluride (CdTe) serves as a vital photovoltaic technology that employs a thin film of CdTe to convert sunlight into electrical energy, rapidly gaining acceptance and becoming the second most widely used solar cell material after silicon.

Advantages of CdTe Solar Panels

CdTe panels come with several merits over conventional silicon technology, including:

1. Cost-effective Manufacturing: The production costs for CdTe panels are lower compared to silicon-based solar panels. First Solar was the first company to manufacture CdTe panels at less than $1.00 per watt, with prospects of lowering it to approximately $0.50 per watt in the future, potentially leading to installed systems around $1.5/W.
2. Optimum Sunlight Absorption: Cadmium Telluride captures sunlight at an ideal wavelength, effectively harnessing energy at shorter wavelengths than silicon panels can achieve.
3. Abundance of Cadmium: Cadmium is produced as a by-product of other essential metals, meaning it experiences less price fluctuation compared to silicon.

Drawbacks of Cadmium Telluride

Despite its benefits, CdTe solar panels do have drawbacks:

1. Lower Efficiency: CdTe solar panels currently achieve efficiency levels around 10.6%, significantly lower than typical silicon solar cell efficiencies.
2. Limited Tellurium Supply: Although cadmium is relatively abundant, tellurium is not, making it a critical factor for the widespread adoption of CdTe panels.
3. Toxicity Concerns: Cadmium is known to be toxic. While CdTe is less harmful than elemental cadmium in acute exposure scenarios, it still poses risks if mishandled.

Research indicates that the large-scale use of CdTe PV modules poses no significant health and environmental risks, and efforts to recycle these modules after their life cycle mitigate potential environmental issues. Additionally, during operation, these modules do not emit pollutants and provide substantial environmental benefits by replacing fossil fuels. For more Custom Developer Solutions for Solar Cells information, please contact us for professional insights.

Current Research Endeavors

Research focusing on CdTe is addressing several key challenges:

1. Enhancing efficiency via innovative transparent conducting oxides that improve light absorption and current collection.
2. Examining grain boundaries that may limit cell voltage.
3. Understanding degradation in CdTe devices and developing strategies to reduce this impact.
4. Creating module designs that protect outdoor exposure to moisture.
5. Conducting rigorous stress testing for both indoor and outdoor environments.

The continued evolution and acceptance of CdTe solar technology are crucial to meeting global energy demands while minimizing environmental impacts. As it stands, this technology remains a significant player in the future landscape of renewable energy sources.