Australia’s first virtual tandem solar cell fabrication platform delivers world record efficiencies

In 2025 UNSW successfully completed commissioning of ACAP’s new Tandem Cluster, a major research infrastructure and the first of its kind in Australia.

The final component – the broadband antireflection coating (ARC) deposition system – was commissioned in December 2025, completing a staged installation of tools delivered between 2023 and 2025.

Led by Scientia Professor Xiaojing Hao, Professor Nicholas J. Ekins‑Daukes, Professor Bram Hoex, and Professor Ziv Hameiri, the project has established Australia’s first virtual tandem fabrication cluster. This integrated suite of sputtering, evaporation, ALD and in‑situ characterisation systems now provides ACAP researchers with a unified platform for fabricating next‑generation tandem solar cells.

Throughout 2024–2025, the cluster directly supported multiple UNSW thin‑film top‑cell projects, including kesterite and chalcogenide (CZTS and CIGS) and wide‑bandgap perovskite programs. These projects have already delivered certified world‑record efficiencies: 13.2% for CZTS, 14.9% for CIGS, and 21.8% for wide‑bandgap perovskite top cells.

Professor Xiaojing Hao said, “These achievements highlight the impact of the new infrastructure in accelerating device development and improving interface quality, uniformity, and contamination control across fabrication steps.”

Beyond individual records, the cluster is enabling more reproducible, scalable tandem‑cell fabrication and paving the way for future technology transfer at high TRLs. By integrating UNSW’s Si cell manufacturing capabilities with high‑bandgap thin‑film expertise, the facility positions Australia at the forefront of tandem PV innovation and strengthens national capacity for next‑generation, high‑efficiency photovoltaic technologies.

Atomic Layer Deposition (ALD) for sulfide and oxide function layer materials

Dual-source e-beam evaporator for anti-reflection coating (ARC) materials.

Multi-source evaporator for high bandgap adamantine absorber.

Multi-chamber sputters for functional layers.

Evaporator for selective transport materials integrated with glovebox.