TOPCon

TOPCon stands for Tunnel Oxide Passivated Contact, a next-generation solar cell architecture that improves on PERC technology by adding an ultra-thin tunnel oxide layer and a doped polysilicon layer to the rear of the cell. This structure dramatically reduces electron recombination losses at the contact points.

Where PERC cells top out around 23% to 24% cell efficiency in mass production, TOPCon cells are achieving 25% to 26% and climbing. The technology's theoretical efficiency ceiling is higher than PERC, giving manufacturers a longer runway for incremental improvements.

A major advantage of TOPCon is that it can be manufactured on existing PERC production lines with relatively modest equipment upgrades. This has accelerated adoption — several major Chinese manufacturers have converted significant portions of their capacity to TOPCon, and it is rapidly becoming the new mainstream cell technology.

TOPCon cells also exhibit a better temperature coefficient than PERC, meaning they retain more of their rated output in hot conditions. Their bifacial gain (ability to capture light from both sides) is also higher, making TOPCon particularly attractive for ground-mount and tracker systems where reflected light hits the rear of the panel.

For buyers comparing panels, TOPCon modules represent the leading edge of widely available technology in the current market.