CdSCdTe

CdSCdTe refers to the CdS/CdTe solar cell structure, a widely studied thin-film photovoltaic technology that uses a cadmium sulfide (CdS) window layer in combination with a cadmium telluride (CdTe) absorber. In these devices, CdS forms a wide-bandgap, n-type window layer that helps collect and transport photogenerated electrons, while CdTe serves as the light-absorbing p-type layer. The CdS/CdTe junction creates a heterojunction diode that converts sunlight into electrical energy.

CdS and CdTe have complementary properties that make them suitable for high-efficiency thin-film solar cells. CdS has a bandgap of about 2.4 eV, which reduces parasitic absorption and permits transparency for visible light to reach the CdTe layer. CdTe has a nearly ideal bandgap around 1.45–1.5 eV for single-joss solar energy conversion, enabling strong absorption with relatively thin active layers. Typical device architectures place CdS as a thin shell on top of the CdTe absorber, with CdTe thickness in the micrometer range and CdS layer in the tens to low hundreds of nanometers. Deposition methods commonly used include chemical bath deposition for CdS and close-spaced sublimation or vapor deposition for CdTe. Additional layers, such as back-contact metallization or surface-treated interfaces, are employed to improve contact quality and stability.

Performance and development have made CdS/CdTe one of the leading thin-film photovoltaic options, with laboratory efficiencies exceeding 22% and commercial modules achieving competitive performance in the past decades. The technology benefits from relatively low material usage and mature manufacturing processes, but it involves cadmium-containing components, which raises environmental and safety considerations. Ongoing research focuses on improving interface passivation, contact stability, and long-term durability, while addressing recycling and regulatory aspects associated with cadmium-containing devices.