Product Information | Cadmium Telluride Power Generation Glass - Enabling a Green New Future for Integrated Building Photovoltaics (BIPV)

I. Introduction to Cadmium Telluride Materials

Cadmium telluride (CdTe) belongs to the II-VI group of compound semiconductors. It possesses a direct bandgap of 1.45 eV and a high optical absorption coefficient (>5×10⁵ cm⁻¹). Calculations of the relationship between the conversion efficiency of ideal solar cells and the bandgap width show that CdTe's spectral response closely matches the solar spectrum. This means that a CdTe film just 2 mm thick can absorb 99% of sunlight at AM 1.5. The mm-scale minority carrier diffusion length allows nearly all photogenerated carriers to be collected by the contact electrodes, significantly reducing material quality requirements. With continued advancements in scientific research, CdTe will become an ideal material for achieving high-efficiency solar cells.

II. Development of Cadmium Telluride Solar Cell Materials

1. Cadmium telluride (CdTe) first emerged as a new electrical material in 1947. French scientists prepared CdTe crystals by evaporating Cd and Te in a hydrogen atmosphere. They then measured the photoconductivity and crystal properties, beginning to study CdTe as an optical material.

2. Rappaport diffused indium into p-type CdTe crystals to produce a CdTe single-crystal cell with a conversion efficiency of approximately 2% (Voc = 600 mV, Jsc approximately 4.5 mA/cm², fill factor 55%).

3. In 1979, a CNRS research group in France fabricated a device with a conversion efficiency exceeding 7% by depositing p-type arsenic-doped CdTe thin films onto n-type crystals using close-space vapor deposition (VTD).

4. In 1981, Kodak used close-space sublimation (CSS) technology to produce the world's first CdTe solar cell with a conversion efficiency of 10% and also fabricated the first solar cell module (12 cells, 8% efficiency).

5. In 1992, by adding a tin oxide interlayer to the TCO/CdS/CdTe structure and reducing the thickness of the CdS layer, the efficiency of CdTe cells exceeded 15%.

6. Since the beginning of the 21st century, thin-film solar cells, represented by cadmium telluride thin-film solar cells, have attracted considerable attention. Many international companies and organizations have begun research and testing, achieving large-scale production of cadmium telluride thin-film solar cells. In recent years, my country's cadmium telluride thin-film solar cells have experienced rapid development, from basic laboratory research to industrial applications. Research focuses on high conversion efficiency, low cost, and high stability, rapidly propelling my country's cadmium telluride thin-film solar cell industry into the forefront of the world.

III. Cadmium Telluride (CdTe) Thin-Film Solar Cell Structure

Cadmium telluride solar cells primarily utilize thin-film deposition technology to deposit a cadmium telluride thin film on a conductive substrate. A PN junction is then formed through processes such as doping and evaporation.

(1) Glass substrate: mainly acts as a support for the battery, preventing pollution and incident sunlight;

(2) TCO layer: transparent conductive oxide layer. It mainly plays the role of light transmission and conductivity;

(3) CdS window layer: n-type semiconductor, forming a p-n junction with p-type CdTe;

(4) CdTe absorption layer: it is the main light absorption layer of the battery, and the p-n junction formed with the n-type CdS window layer is the core part of the entire battery;

(5) Contact layer and electrode: in order to reduce the contact barrier between CdTe and the metal electrode, draw out the current, and make the metal electrode and CdTe form an ohmic contact.

IV. Characteristics of Cadmium Telluride (CdTe) Thin-Film Solar Cells

1. High Photovoltaic Conversion Efficiency: Cadmium telluride (CdTe) is a direct-gap material with excellent absorption across the entire spectrum. Experimental data shows that its theoretical conversion efficiency can reach 33%. Currently, domestic companies specializing in the R&D of CdTe thin-film solar cells, such as Zoom Solar Green Energy Technology Co., Ltd., have developed and produced CdTe thin-film solar glass products that have reached the internationally leading level of 17%.

2. Excellent Low-Light-Power Performance: Compared with traditional crystalline silicon solar cells, CdTe maintains high power generation efficiency even in low-light conditions (such as early morning, cloudy days, evening, rainy and snowy days), providing a more stable energy supply.

3. Low Temperature Coefficient: PV modules made of CdTe thin-film photovoltaic cells are also double-glass modules, impervious to damage from external impacts such as breakage, cracking, and poor welding quality. Furthermore, the modules are less susceptible to degradation, are lighter in weight, and have excellent temperature resistance. In areas with good sunlight, the temperature coefficient of CdTe modules is approximately -0.25%/°C, making them more suitable for harsh environments such as high temperatures.

4. High Degree of Customization: CdTe thin-film solar glass products offer uniform color, a stylish appearance, low breakage rate, a low carbon footprint, and low manufacturing costs, making them particularly suitable for buildings requiring high aesthetics. They can be flexibly customized to meet BIPV project requirements, including color, pattern, thickness, light transmittance, shape, and dimensions. They can be effectively integrated with modular, unitized, and semi-unitized curtain wall systems, truly enabling photovoltaic building materials to replace traditional building materials in architectural applications.

V. Applications of CdTe Thin-Film Solar Glass Products in BIPV

With the continuous advancement of technology and reduction in costs, CdTe thin-film solar glass products, as a highly efficient and environmentally friendly BIPV material, have enormous potential for application in the renewable energy sector. Zoom Solar Green Energy Technology Co., Ltd., with the mission of "Enhancing Value through Technology, Transforming Life through Green," is committed to becoming a global leader in green and sustainable development. In recent years, Zhongmao Green Energy's cadmium telluride thin-film power generation glass products have achieved widespread success in building photovoltaic integration (BIPV) applications, injecting strong impetus into the green transformation and sustainable development of the construction industry.