Optimized NiTe2/Ni Back Contacts via Chemical Deposition for High Performance CdTe Solar Cells

Journal Article · Sun Nov 30 00:00:00 EST 2025 · Solar Energy Materials and Solar Cells

DOI:https://doi.org/10.1016/j.solmat.2025.114091· OSTI ID:3014950

Gasparin, Fabiano ^[1]; Sartor, B. Edward ^[2]; Duenow, Joel ^[2]; Colegrove, Eric ^[2]; Brown, Joshua ^[2]; Martinez, Amanda ^[3]; Rozzell, Jamie ^[3]; Reese, Matthew ^[2]

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1. Federal University of Rio Grande do Sul
2. National Laboratory of the Rockies, Golden, CO (United States)
3. Conti Innovation Center

The development of efficient and stable back contacts remains a major challenge in achieving high performance and long-term stability of CdTe thin-film solar cells. This work revisits the formation of NiTe2 by chemical bath deposition (CBD) as a back contact for CdTe devices. An optimized CBD recipe, based on high-purity precursors and the addition of copper chloride directly into the bath, was developed and applied to fabricate Cu-doped CdTe solar cells. A modified Cu-free methodology was also applied to Group V doped absorbers. The process included pinhole filling, ion milling, CBD, annealing, and sputtering to form a low-barrier back contact. Devices fabricated using this method achieved consistent open-circuit voltages (Voc) above 800 mV and fill factors (FF) exceeding 70 %. The best Cu-doped devices reached power conversion efficiencies (PCE) above 18 %, and preliminary results with Group V-doped material demonstrated compatibility of the method with high-efficiency, state-of-the-art CdTe devices. This study shows that NiTe2/Ni back contacts, formed via an optimized chemical process followed by sputtering of Ni, represent a promising pathway for achieving low-barrier and potentially stable back contacts in modern CdTe photovoltaics.

• Research Organization: National Laboratory of the Rockies (NLR), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
• DOE Contract Number: AC36-08GO28308
• OSTI ID: 3014950
• Report Number(s): NLR/JA-5K00-96825
• Journal Information: Solar Energy Materials and Solar Cells, Journal Name: Solar Energy Materials and Solar Cells Vol. 296
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
back contact
CdTe solar cell
nickel telluride