Researchers in China have created new Silver Pastes for Topcon Solar Cell Leco production. The new pastas integrate aluminum, gallium or iron and are said to be securely anchored to keep the electrodes of cells safely anchored to the silicon cell surface due to the improved stability of the lead oxide (PBO) component in the glass powder.
A group of researchers led by the Chinese Academy of Sciences claims to have an improved quality of the silver paste for producing solar cells based on tunneloxide-passivated contact (topcon) solar cells via the so-called laser-improved contact optimization (LECO) process.
The process is carried out after firing the metallization paste and includes scanning a laser over a crystalline silicon cell while it is under inverted bias. The result is that free carrier electrons are forced between the metal contact and the silicon, creating a new structure on the edge of the contact and drill-emitter layer surface-a power-supplied contact (CFC). Based on the new CFC structure, topcon cells that undergo the Leco process show no contact resistance after thermal bicycles.
“An urgent improvement in Leco-compatible silver pastas is required to guarantee the reliability and stability of topcon sun cells,” said the corresponding author of the research, Jiangtao di, said PV -Magazine. “Here we have studied optimizing glass formation by introducing elements such as aluminum, gallium and iron in the inorganic glass frits of conductive silver pasta’s.”
The research group created new types of Leco Silver pastes that integrate aluminum (Al), Gallium (GA) and iron (FE) into the Glass Frits, with the aim of evaluating them Sour corrosionability due to the degradation test of acetic acid.
“We investigated the demolition of Topcon sun cells under standard acetic acid conditions,” Di explained. “The silver pasta manufactured with glass frit that contain added al, GA or FE elements, showed a considerably improved resistance to acetic acid corrosion compared to silver paste that miss these special elements.”
The analysis showed that the new glass fries ensured that the electrodes of cells remained safely anchored to the silicon cell surface due to the improved stability of the lead oxide (PBO) component in the glass powder.
“The efficiency loss of leco-used silver paste with al/go/fe additives during exposure to acetic acid can be less than 10%, and even as low as 5%,” went further. “Without the introduction of these special elements, the degradation effect of acetic acid can increase considerably to more than 50%.”
“Our work offers very reliable Leco-compatible silver pasta for topcon sun cells,” he concluded.
The research findings are available in the study “Reinforcement of Topcon Solar Cell Reliability via AL/GA/FE-Adjusted Glass Friets in Leco-compatible silver pastes against acid corrosion“Which was recently published in Solar energy materials and solar cells.
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