CuSCN as the Back Contact for Efficient ZMO/CdTe Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Zinc magnesium oxide (ZMO) offers improved power conversion efficiency (PCE) in cadmium telluride (CdTe) solar cells compared to traditional cadmium sulfide (CdS) buffers.
• ZMO's atmosphere sensitivity presents challenges for critical post-deposition treatments in high-performance CdTe solar cell fabrication.

Purpose of the Study:

• To investigate copper thiocyanate (CuSCN) as a suitable back-contact material for ZMO/CdTe solar cells.
• To address the challenges associated with post-treatment of ZMO/CdTe stacks.

Main Methods:

• CuSCN was deposited as a back contact using ammonium hydroxide as a solvent, ensuring no detrimental impact on the ZMO layer during post-heat treatment.
• Optimization of post-annealing temperature and CuSCN film thickness was performed.

Main Results:

• A champion power conversion efficiency (PCE) of 16.7% was achieved for the ZMO/CdTe solar cells.
• Key performance metrics include an open-circuit voltage of 0.857 V, a short-circuit current density of 26.2 mA/cm², and a fill factor of 74.0%.

Conclusions:

• Copper thiocyanate (CuSCN) is a promising back-contact material for ZMO/CdTe solar cells, compatible with ZMO layers.
• The use of ammonium hydroxide as a solvent for CuSCN deposition facilitates successful post-treatments, enabling high-performance CdTe solar cells.