Hierarchical Transparent Back Contacts for Bifacial CdTe PV

Area of Science:

• Materials Science
• Photovoltaics
• Nanotechnology

Background:

• Transparent back contacts are crucial for efficient solar cell performance.
• Copper-free Cadmium Telluride (CdTe) devices require optimized back contact strategies.
• Existing methods face challenges in balancing open-circuit voltage and fill factor.

Purpose of the Study:

• To develop and demonstrate a hierarchical transparent back contact for copper-free CdTe solar cells.
• To investigate the role of AlGaO subscript passivating layer and Ti subscript 3 subscript C subscript 2 subscript T subscript MXene interlayer.
• To evaluate the bifacial performance and efficiency of the novel contact design.

Main Methods:

• Fabrication of a hierarchical transparent back contact using AlGaO subscript , Ti subscript 3 subscript C subscript 2 subscript T subscript MXene, and transparent cracked film lithography (CFL) templated nanogrid.
• Integration of the contact onto copper-free, group-V doped CdTe devices.
• Characterization of device performance under 1-sun and dual illumination conditions.

Main Results:

• The AlGaO subscript layer improved open-circuit voltage, while the Ti subscript 3 subscript C subscript 2 subscript T subscript interlayer enhanced fill factor and reduced Schottky barriers.
• The hierarchical contact enabled efficient metallization with CFL, providing transverse conduction.
• Frontside efficiency reached 19.5% and backside efficiency reached 2.8% for bifacial CdTe devices.
• Dual illumination (1-sun frontside, 0.1-sun backside) achieved a power generation of 200 W/m super 2 super .

Conclusions:

• The demonstrated hierarchical transparent back contact significantly improves the performance of copper-free CdTe solar cells.
• The combination of AlGaO subscript , Ti subscript 3 subscript C subscript 2 subscript T subscript , and CFL nanogrid is a promising strategy for advanced photovoltaic devices.
• This approach offers potential for enhanced bifacial energy harvesting and overall device efficiency.