Renewables
Addressing degradation in copper-plated solar cells
Researchers have identified a solution to screen printing wear in copper-plated heterojunction solar cells, enhancing manufacturing reliability.
Key points
- Screen printing wear damages passivating contact structures in copper-plated heterojunction solar cells.
- Chinese researchers introduced an emulsion buffer layer to prevent direct mesh contact with wafers.
- Copper metallization offers a cost-effective alternative to expensive silver in solar cell manufacturing.
What happened
pv magazine reported that researchers in China have investigated structural damage caused by screen printing during the fabrication of copper-plated silicon heterojunction solar cells. While copper plating provides an economical substitute for costly silver metallization, mechanical pressure and thermal cycles during production can impair sensitive passivating contact layers. Consequently, devices suffer from reduced conversion efficiencies and higher recombination losses.
According to the reporting, consecutive printing cycles lead to a gradual decline in device performance, with efficiency dropping significantly over extended runs. Microscopic analysis revealed that progressive wear on the screen mesh knuckles increases the contact area with the silicon wafer, generating harmful mechanical stress on the underlying interfaces. Unlike traditional silver paste methods that utilise an emulsion layer covering most of the screen, full-area photoresist applications for heterojunction cells historically allowed the mesh to make extensive contact with the wafer during every cycle.
Mitigation strategies
To counteract this cumulative damage, the scientific team introduced a modified screen design incorporating an emulsion buffer layer. This modification successfully prevents direct physical contact between the abrasive mesh and the wafer. After testing various coverage ratios, the investigators determined that an optimal balance could be achieved, maintaining coating uniformity while minimising minority carrier lifetime degradation during thousands of test cycles.
Additional research highlighted globally points toward increasing momentum in silver-free solar manufacturing. Institutions in China and Germany have recently achieved notable conversion efficiencies using various copper electroplating and hybrid paste configurations, demonstrating the technological viability of moving away from silver.
Why it matters
For energy investors and manufacturers across the globe, scaling up low-cost metallization techniques is critical to lowering photovoltaic module expenses. As the global renewable energy sector expands—with world electricity use averaging 3,708.5 kWh per person in 2024 according to World Bank figures provided in CEII data—reducing production costs without sacrificing efficiency accelerates the global energy transition. For emerging markets and regions seeking to diversify industrial capabilities, robust manufacturing reliability in advanced solar technologies ensures long-term economic viability and broader deployment of clean power infrastructure.
Original reporting
This article draws on the following reports. Read them in full on the publishers’ sites.
Context from CEII
Renewables are the fastest-growing part of the world’s energy system. The COP28 goal is to triple capacity by 2030, and solar mini-grids are the fastest route to power for millions of people without electricity.
28.4% of electricity in China was renewable in 2021Countries in this story
Written by the CEII Desk, the Centre’s automated newsroom, from the reporting credited above and CEII’s own data. Facts are attributed to their sources; the publishers have not reviewed this article. Spotted an error? Tell our editors.
