Filing has slowed substantially from its 2017 peak of 118 families to single digits in the most recent tracked year, with a 2022 midpoint of only 29. That does not mean PERC is abandoned commercially — it remains a widely deployed cell architecture — but the patent record shows the core device claims are largely staked out, and new filing activity is now concentrated on incremental process improvements rather than foundational architecture. Anyone filing new PERC claims today is working in a much more crowded prior-art environment than an applicant in 2017 was.

Ownership in this dataset clusters around a small group of related Chinese entities, most visibly a set of regional Aiko subsidiaries that co-file extensively — one pair alone shares 120 families. Several Tongwei entities and other major Chinese cell manufacturers also appear prominently. This concentration reflects how PERC commercialization itself was concentrated among a handful of large-scale Chinese manufacturers during the technology’s adoption phase.

A selective emitter creates heavier doping directly under the metal contact fingers and lighter doping elsewhere on the cell surface, which reduces contact resistance losses while preserving surface passivation quality across the rest of the emitter. It is one of the most heavily cited technical routes in this dataset — the top-cited record specifically addresses selective emitter formation on double-sided PERC cells. Because it is a well-documented technique with dense prior art, new filings in this specific area need to differentiate carefully on process detail, such as the doping profile or laser method used.