Rethinking silver: ACAP and ARENA supported research team is solving solar’s looming supply constraint

As the global solar industry accelerates toward terawatt-scale manufacturing, it faces a critical bottleneck: silver. Today’s high-efficiency silicon solar cells rely on screen-printed silver contacts, and in 2025 alone, photovoltaic manufacturing consumed roughly 25% of global silver supply, highlighting the material risk of scaling solar without redesigning how critical resources are used. 

With the support of the Australian Centre for Advanced Photovoltaics, Associate Professor Brett Hallam and his metallisation team at UNSW Sydney, including Dr Li Wang, Dr Yuchao Zhang, Dr Yuan-Chih Chang, Dr Sisi Wang and colleagues, have developed a practical, industry-ready solution. Their silver-lean screen-printing technology dramatically reduces silver use in high-efficiency TOPCon solar cells while remaining fully compatible with existing production lines. 

Rather than printing continuous silver fingers and busbars, the team uses silver only where it is electrically essential – as microscopic ‘dashes’ at the silicon interface. The bulk of the conductive structure is then formed using silver-lean or silver-free pastes such as silver-coated copper, pure copper or aluminium. The result: up to 85% reduction in rear-side silver consumption without sacrificing cell efficiency,¹,² and a path to overall silver consumption as low as 2 mg/W. 

ACAP supported research at UNSW shows a silver-lean “dash” contact design can cut silver use to around 2 mg/W – with up to 85% reduction – without sacrificing efficiency.

The approach builds on a multi-year research arc defining the material intensity limits required for sustainable terawatt-scale manufacturing³.  

At  SiliconPV 2025 in Oxford, Dr Li Wang delivered the presentation with the highest-ranked abstract of the conference, Ultra-Lean Silver Screen-Printing for Sustainable Terawatt-Scale PV¹.  

“If photovoltaics is to scale sustainably to the terawatt level, we must reduce silver consumption to less than2 milligrams per watt – our approach opens more opportunities for adopting alternative materials to achieve this goal,” said Dr Wang. 

A complementary 2025 study in Solar Energy Materials & Solar Cells demonstrated 25%-efficient industrial TOPCon cells with ultra-low silver consumption under industry-relevant conditions².  

“This is not just a laboratory concept,” said Associate Prof Hallam. “We are showing a manufacturable pathway that removes a key materials constraint for global PV deployment at the terawatt scale.” 

The work has attracted significant international media attention, including coverage in PV Magazine (international and Australian editions), reflecting growing industry recognition that material intensity – not just efficiency – will define the next phase of solar competitiveness. 

Critically, the technology has been developed in close collaboration with industry partners Toyo Aluminium, Fusion New Materials and Copprint (wleading paste formulation development) while UNSW defined performance specifications, conducted integration and validated reliability. Initial pilot production batches have confirmed compatibility with existing flatbed screen-printing lines and soldered interconnection processes. 

Sustained investment delivers industry ready results

The progression of this breakthrough reflects coordinated national investment.   

Early-stage modelling and roadmap development were supported by ACAP, enabling the team to propose a roadmap towards 5 mg/W and 2 mg/W silver consumption for industrial screen-printed silicon solar cells, and to investigate a hybrid plating/printing approach which achieved up to 40%_rel reduction in finger silver consumption (although this was not the main approach to achieve ultra-low silver consumption target³).  

Later, work focusing on silver reduction using a screen-printing approach was supported by an ARENA TRAC project, enabling the team to realise up to 85% reduction in rear-side silver consumption, without sacrificing cell efficiency and a path to overall silver consumption as low as 2 mg/W, which is required for sustainable multi-terawatt manufacturing^1,2.  

Together, this layered funding model demonstrates how strategic public investment can anticipate a global supply constraint and deliver an industry-ready solution before it limits deployment.  

The next phase (2026–2027) focuses on industrial optimisation, Tier-1 pilot production and commercial licensing – positioning silver-lean metallisation as a pathway to cost-competitive, resource-efficient solar manufacturing at global scale. 

References 

1. Zhang, Y., Wang, S., Wang, L., Sun, Z., Chang, Y.-C., Chen, R., Chan, C., Sun, L., Cheng, Y., Song, N. & Hallam, B. (2024). Ultra-lean silver screen-printing for sustainable terawatt-scale photovoltaic. Solar RRL 8, 2400478. https://doi.org/10.1002/solr.202400478 

2. Zhang, Y., Wang, S., Wang, L., Chang, Y.-C., Chen, R., Chan, C., Sun, L., Cheng, Y., Song, N., Okamoto, K., Ao, Y., Wang, D. & Hallam, B. (2025). Silver-lean screen-printing metallisation for industrial TOPCon solar cells: enabling an 80% reduction in silver consumption. Solar Energy Materials & Solar Cells 288, 113654. https://doi.org/10.1016/j.solmat.2025.113654 

3. Chang, Y.-C., Zhang, Y., Wang, L., Wang, S., Wang, H., Huang, C.-Y., Chen, R., Chan, C. & Hallam, B. (2024). Silver-lean metallization and hybrid contacts via plating on screen-printed metal for silicon solar cells manufacturing. Progress in Photovoltaics: Research and Applications. https://doi.org/10.1002/pip.3799