The dataset shows activity concentrated among Korean national research institutes, notably Korea Institute of Energy Research and Korea Institute of Science and Technology, alongside US university-affiliated filers such as the University of Illinois research council and the University of Texas System. No single assignee dominates the full 50-family set; the pattern is a moderate cluster of institutional filers followed by a long tail of single-filing entrants. None of the leading assignees show filings in the most recent tracked year, which is consistent with the overall flat-to-declining trend rather than one company's specific withdrawal.

No — filings peaked at 4 families in 2017, fell to 1 by the 2022 midpoint, and have continued to decline through the most recent tracked years. Because publication lags filing by roughly 18 months, the very latest year always looks lower than it will eventually turn out to be, so a single down year is not conclusive. But the multi-year trend from 2017 onward is a genuine decline, not a data artefact, and it points to a field where the core claim space was largely staked out in the mid-2010s.

This Korea Institute of Energy Research filing claims a three-stage co-evaporation method for forming the CIGS absorber layer: a first stage co-evaporating indium, gallium and selenium, a second stage co-evaporating copper and selenium, and a third stage repeating indium, gallium and selenium deposition, with gallium supply in the first stage exceeding that in the third. It is specifically framed as a fix for substrates with low sodium concentration, where the depletion layer would otherwise be too thick. Anyone using an asymmetric three-stage Ga-grading sequence with that particular first-stage-heavy gallium profile should check this filing's claim scope directly rather than assume a generic three-stage process is clear.

The United States receives the largest share of filings by a wide margin — 29 of 50 tracked families — with South Korea a distant second at 6, followed by WIPO PCT filings at 5 and Taiwan at 4. China and India each show only 2 filings in this dataset. For a company manufacturing or selling in China or India, that low count is worth treating as an opportunity to check for gaps rather than as evidence the field is unclaimed there, since global applicants may simply not have prioritised filing in those offices yet.

Relative to the dense core cluster in H01L absorber-deposition claims, several adjacent branches show thin coverage: alkali post-deposition treatment control, wide-bandgap grading near the back contact, roll-to-roll flexible substrate integration, cadmium-free buffer layer pairing, and nanoparticle precursor ink formulation. These sit at the edges of the IPC composition data, in classes like C23C, B22F and H02S, rather than in the main H01L cluster. A first claim in one of these areas is more likely to clear prior art cleanly than another absorber-composition filing in the core space.