CIGS Solar Cell Reliability Patents: Leaders, Trends & Gaps 2026
- Filings peaked in 2020 at 31 and have declined since, with 2022 sitting at 18 — the growth phase for this specific claim space has already passed, even accounting for publication lag.
- H01L dominates at 252 of 348 records, but H10K organic-semiconductor crossover claims (164) show reliability work increasingly borrows from adjacent thin-film device architectures.
- The most-cited records are two decades-old nanowire patent families, not recent damp-heat or encapsulation filings — current durability claims have not yet built comparable citation weight.
Filing growth compares 2021 (8 records) with 2024 (11) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 348 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This dataset tracks patent families addressing CIGS thin-film solar cell durability — long-term stability, damp-heat resistance and degradation resistance — published between 2015 and mid-2026. The search combines core CIGS material terms with reliability-specific language, isolating filings that go beyond general CIGS cell design to address failure modes and lifetime performance specifically.
Filing activity is concentrated in the United States receiving office, with meaningful volume also routed through the EPO, WIPO/PCT and India. Publication for the most recent one to two years is understated because of the roughly 18-month lag between filing and publication, so the apparent 2025-2026 decline should be read cautiously rather than as a confirmed drop-off.
Filing trend and technology composition
Two views of the same 348-family corpus: how filing volume has moved year over year, and which IPC subclasses carry the claim weight.
A peak in 2020, then a decline
Annual filings rose to 31 in 2020, then eased toward a midpoint of 18 in 2022. Combined with a partial-year 2026 figure of 2, the pattern reads as flat-to-declining rather than an accelerating field, though the final two years will revise upward as publications catch up.
H01L dominates, H10K is a large second
Semiconductor devices (H01L) account for 252 of 348 records, confirming that most durability claims are filed as device-level semiconductor art rather than pure materials chemistry. The 164 records touching H10K (organic semiconductor structures) point to meaningful overlap with adjacent thin-film device work, while C23C coating/deposition (38) and B82Y nanotechnology (26) represent smaller, more specialised pockets.
Shares are the percentage of the 348 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on CIGS Solar Cell Reliability and Durability with Eureka
This page is one run against one query. Ask Eureka your own question about cigs solar cell reliability and durability and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited records and a representative filing
US20130206232A1 — Nanowires and methods of making and using
Nanorod and nanowire compositions are disclosed comprising copper indium selenide, copper indium gallium selenide, copper indium sulfide, or a combination thereof. Also disclosed are photovoltaic devices comprising the nanorod and/or nanowire compositions. Also disclosed are methods for producing the nanorod and nanowire compositions, and photovoltaic devices described herein.Filed by the Board of Regents, The University of Texas System — illustrates how early nanowire/nanorod composition claims underpin later CIGS device and durability filings.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20080143906A1 | Nanowire-based transparent conductors and applications thereof | 531 |
| 2 | WO2014045021A1 | Optoelectronic device | 516 |
| 3 | WO2008046058A2 | Nanowire-based transparent conductors and applications thereof | 218 |
| 4 | US20100243295A1 | Nanowire-based transparent conductors and applications thereof | 214 |
| 5 | US20150249170A1 | Optoelectronic device | 195 |
| 6 | US8094247B2 | Nanowire-based transparent conductors and applications thereof | 138 |
| 7 | US8018568B2 | Nanowire-based transparent conductors and applications thereof | 132 |
| 8 | US7319190B2 | Thermal process for creation of an in-situ junction layer in CIGS | 131 |
| 9 | US20110088770A1 | Nanowire-based transparent conductors and applications thereof | 105 |
| 10 | US20030230338A1 | Thin film solar cell configuration and fabrication method | 102 |
Citation counts favour older filings that have had more time to accumulate references within the searched corpus — treat them as a measure of historical influence, not of which claims matter most today.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three patterns stand out once family counts, IPC spread and receiving offices are put side by side.
The volume peak has already passed
Annual filings crested at 31 in 2020 and had fallen to 18 by 2022, with the 2026 partial-year count at just 2. This is a maturing claim space rather than an emerging one — new entrants are filing into territory that has already been substantially staked out.
US filing leads, but PCT/EPO routes are substantial
With 141 records at the United States office against 52 at the EPO and 49 filed via WIPO/PCT, durability-focused CIGS art is being protected across multiple jurisdictions rather than concentrated in one market, which raises the bar for freedom-to-operate clearance.
Durability claims sit across two device architectures
The heavy overlap between H01L semiconductor-device claims and H10K organic-semiconductor claims suggests reliability improvements are frequently framed at the device-stack level, not isolated to the CIGS absorber layer alone.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to cigs solar cell reliability and durability, with the prior art for and against each one.
| Assignee | Co-assignee | Shared families |
|---|---|---|
| City University of Hong Kong | Imperial Innovations Limited | 7 |
| Oxford University Innovation | Oxford Photovoltaics Limited | 6 |
| SARGENT EDWARD HARTLEY | LEVINA LARISSA | 5 |
| SARGENT EDWARD HARTLEY | KOLEILAT GHADA | 5 |
| Cambio Tech | SPAID MICHAEL A | 3 |
| Cambio Tech | SHUO | 3 |
| Cambio Tech | DAI HAIXIA | 3 |
| SARGENT EDWARD HARTLEY | TANG JIANG | 3 |
Ten co-assignee pairs appear in the dataset; the strongest pairings link university innovation offices to spinout or industry partners, consistent with academic-to-commercial technology transfer in this field.
Who holds the ground, and where it is open
Recent-year momentum figures show several previously active assignees recording zero filings in the latest year — a signal of either portfolio maturity or a shift in filing strategy, not necessarily reduced interest in the underlying technology.
Top historical filers have gone quiet recently
Assignees including Oxford University Innovation, Cambio Tech, and the Board of Trustees of the Leland Stanford Junior University show zero filings in the most recent year, consistent with publication lag but also suggesting portfolios in this niche were built earlier and are now being maintained rather than expanded.
University-to-spinout pairing is the dominant collaboration model
The strongest co-assignee pairs link university innovation offices to affiliated commercial entities — City University of Hong Kong with Imperial Innovations, and Oxford University Innovation with Oxford Photovoltaics — pointing to academic labs as the primary source of durability innovation, commercialised through dedicated spinouts.
Named-inventor co-filing also appears at meaningful scale
Beyond institutional pairs, individually named inventor teams filing jointly account for some of the strongest co-assignment links in the dataset, suggesting a research-group-centred rather than purely corporate-lab filing pattern in parts of this field.
| Assignee | Recent year | YoY |
|---|---|---|
| Oxford University Innovation | 0 | — |
| Cambio Tech | 0 | — |
| The Board of Trustees of the Leland Stanford Junior University | 0 | — |
| Alliance for Sustainable Energy, LLC | 0 | — |
| JUN Co., Ltd. | 0 | — |
| Materials Innovation Technology Co., Ltd. | 0 | — |
| City University of Hong Kong | 0 | — |
| trinamiX GmbH | 0 | — |
Where to take this analysis
The dataset points to a maturing but jurisdictionally fragmented claim space, with clearer answers available once specific claims and assignees are examined directly.
Check freedom-to-operate against the top-cited families
The nanowire-based transparent conductor and optoelectronic device families carry the highest citation counts in this corpus and are worth clearing first, even though they are not the newest filings.
Explore claims in EurekaMap the under-claimed branches to your own roadmap
Encapsulant interfaces, back-contact corrosion barriers and flexible-substrate delamination show thinner claim density than the core device architecture claims.
Run a white space search in EurekaTrack the academic-to-spinout filing pattern
Several of the strongest co-assignee pairs link university innovation offices to commercial spinouts, a useful signal for identifying early-stage licensing opportunities.
Monitor assignees in EurekaCommon questions about CIGS reliability patents
The dataset shows filings rising to a peak of 31 in 2020 before declining to 18 by 2022. This pattern typically reflects a technology area where the core claim space around damp-heat resistance, encapsulation and degradation testing had already been substantially staked out by early filers, leaving less room for differentiated new claims. It does not necessarily mean research interest declined, only that patenting activity specifically in this claim space slowed. Readers should also account for publication lag, which understates filings in the most recent one to two years.
Ranking data for this corpus shows filing concentrated among a mix of university innovation offices and specialist solar technology firms, with several of the historically most active assignees showing no filings in the latest recorded year. Rather than naming a single leader, it is more useful to look at the co-assignee pairs in the data, which reveal how university research groups have partnered with commercial spinouts to commercialise durability innovations. Checking the full assignee ranking table alongside recent-year momentum gives a clearer picture than any single top-filer claim.
General CIGS solar cell patents cover the base semiconductor structure, absorber layer composition and device architecture, while damp-heat durability and degradation-resistance patents specifically address how the cell performs and fails under humidity, thermal cycling and prolonged environmental exposure. This corpus was built to isolate the latter category by combining CIGS material terms with reliability-specific language. In practice, many filings straddle both categories, which is reflected in the heavy overlap between H01L semiconductor-device claims and adjacent IPC subclasses in this dataset.
Based on the IPC composition and claim density in this dataset, sub-areas such as damp-heat encapsulant interfaces, back-contact corrosion barriers, alkali post-deposition treatment stability and flexible-substrate delamination resistance show thinner claim coverage relative to the dominant H01L device-level claims. This does not guarantee these areas are unpatented, but the relative filing density suggests more open drafting room than the core absorber-layer and device-stack claims. A freedom-to-operate search focused specifically on these narrower branches is the recommended next step before drafting.
Citation counts accumulate over time, so older records such as the nanowire-based transparent conductor families naturally show higher citation totals than recent filings simply because they have been available longer for other patents to cite. This is a known bias in citation-based analysis: it measures historical influence within the searched corpus, not current technical or commercial importance. Recent damp-heat and degradation-resistance filings may be equally or more relevant to current product development even though their citation counts have not yet caught up.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.