A search for new back contacts for CdTe solar cells.

Area of Science:

• Materials Science
• Photovoltaics
• Solid-State Physics

Background:

• Cadmium telluride (CdTe) thin-film solar cells face efficiency limitations.
• Open-circuit voltage loss is primarily caused by high surface recombination and Schottky barriers at the back contact.
• Current back contact materials like ZnTe offer suboptimal performance.

Purpose of the Study:

• To computationally identify novel materials for CdTe solar cell back contacts.
• To find materials offering superior passivation, electron reflection, and hole transport.
• To overcome limitations of existing ZnTe back contacts.

Main Methods:

• First-principles calculations and transport modeling were employed.
• A computational screening of 229 binary and ternary tetrahedrally bonded structures was performed.
• Key material properties evaluated include phase stability, electronic structure, and dopability.

Main Results:

• Several promising candidate materials and alloys were identified, including AlAs, AgAlTe2, ZnGeP2, ZnSiAs2, and CuAlTe2.
• These materials demonstrated favorable properties for back contact applications in CdTe solar cells.
• The study provides guidelines for designing improved hole transport layers.

Conclusions:

• The identified materials offer potential for enhancing CdTe solar cell performance.
• These findings pave the way for next-generation back contact materials.
• Further research into these candidates could significantly advance CdTe solar technology.