Tandem Solar Cell Patents: Leaders, Trends & White Space 2026
- Filing peaked in 2022 at 16 families, and the run rate since has not matched that midpoint — this is a mature, not accelerating, filing wave.
- 94 families sit almost entirely under H01L, with H10K (organic semiconductors) the largest secondary cluster at 18 records, pointing to hybrid architecture interest.
- The US receives 53 of the filings tracked here, more than triple the next-largest office (EPO and India, 14 each), concentrating enforcement risk in one jurisdiction.
What this landscape covers
Tandem solar cell efficiency enhancement is the practice of stacking two or more absorber layers with complementary bandgaps — most commonly a perovskite top cell over a silicon bottom cell, or III-V multijunction stacks — to capture a wider slice of the solar spectrum than a single-junction device can. The patent activity tracked here centres on the mechanisms that make a stack actually perform: current matching between sub-cells, bandgap optimization of the absorber layers, and recombination reduction at interfaces and tunnel junctions. These are the levers that separate a lab-demonstration stack from a commercially viable one.
The corpus spans 2015 through the current filing year, drawing on records classified under core multijunction and thin-film IPC codes (H01L31/0725, H10K30/00, H01L31/078). Because publication lags filing by roughly 18 months, the most recent year's count is necessarily incomplete and should be read as a floor, not a ceiling.
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Filing trend and technology composition
Two views of the same 94-family dataset: how filing activity has moved year over year, and which IPC subclasses the claims actually sit in.
A filing wave that has already crested
Annual filings rose from 4 in 2017 to a peak of 16 in 2022. With 2022 as the midpoint of the tracked range, the flat-to-declining pattern since suggests the core current-matching and bandgap-optimization claim space is now well staked out, rather than still opening up.
Concentrated in H01L, with an organic-semiconductor tail
All 94 records touch H01L (semiconductor devices), the expected home for tandem cell claims. The next largest cluster, H10K at 18 records, covers organic and perovskite-adjacent semiconductor structures — a signal that hybrid perovskite-organic tandem work is a distinct, sizeable sub-thread rather than a rounding error. Smaller counts in H01G, C30B and C22C mark adjacent interests in capacitive structures, crystal growth and alloy interlayers.
Shares are the percentage of the 94 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Tandem Solar Cell Efficiency Enhancement with Eureka
This page is one run against one query. Ask Eureka your own question about tandem solar cell efficiency enhancement and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited prior art in this space
Perovskite-silicon tandem solar cell — US20210273127A1
Perovskite/silicon tandem solar cells have the potential to achieve high efficiencies through improvements to the optical and electrical parameters of perovskite/silicon tandem devices, via photon management, particularly using the optical band-edge shifting properties of silicon via surface modification of silicon. Silicon can directly extract the light generated charge carriers, which can achieve an efficiency of over 28%.Filed by King Fahd University of Petroleum and Minerals, published 2021-09-02.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20140182667A1 | Multijunction solar cell with low band gap absorbing layer in the middle cell | 61 |
| 2 | US20170271622A1 | High efficiency thin film tandem solar cells and other semiconductor devices | 39 |
| 3 | US20170062642A1 | Inverted metamorphic multijunction solar cell | 33 |
| 4 | US6743974B2 | Silicon solar cell with germanium backside solar cell | 30 |
| 5 | US20020179142A1 | Silicon solar cell with germanium backside solar cell | 27 |
| 6 | US20140158189A1 | Areal current matching of tandem solar cells | 14 |
| 7 | US20130327378A1 | Radiation resistant inverted metamorphic multijunction solar cell | 13 |
| 8 | WO2019013630A1 | Solar panel with four terminal tandem solar cell arrangement | 12 |
| 9 | US20170092800A1 | Four junction inverted metamorphic solar cell | 9 |
| 10 | US20160322167A1 | Method of making a germanium perovskite/germanuium thin-film tandem solar cell | 9 |
Citation counts inside a searched corpus skew toward older filings simply because they have had more time to be cited — read this as a map of influential prior art, not of current commercial importance.
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Browse MCP servers →What the numbers imply for a filing decision
Three signals from the dataset that matter more for strategy than the raw counts alone.
The wave has crested, not started
Filings rose steadily from 4 in 2017 to 16 in 2022, then did not sustain that pace. For a technology this far into its filing cycle, new entrants should expect dense prior art on the core current-matching and recombination-reduction mechanisms rather than open ground.
Enforcement risk sits mostly in one office
The United States receives more than three times the filings of the next office. Freedom-to-operate work for a US-market product should weight USPTO prosecution and litigation history heavily; EPO and India each account for 14 records and are worth a secondary check.
Hybrid architectures are a real sub-thread
Nearly one in five records also touches organic-semiconductor classification, not just conventional silicon-based H01L claims. That overlap points to active claiming around perovskite-organic hybrid stacks rather than pure silicon tandem structures.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to tandem solar cell efficiency enhancement, with the prior art for and against each one.
Who is filing, and how tightly they collaborate
Assignee activity in this space shows a small set of named inventors filing repeatedly together, alongside institutional and corporate assignees with lower per-year output.
A tight inventor network anchors much of the activity
Hart John, Derkacs Daniel and Bittner Zachary appear together across a dense cluster of the strongest co-assignee pairs identified in the dataset, each pairing repeated four times. That pattern indicates a small, stable team working the same technical thread rather than scattered independent filers.
Collaboration is the exception, not the rule
With only 10 co-assignee pairs identified across 94 families, most filings here are single-assignee efforts. That leaves room for new institutional entrants to build their own citation base rather than needing to partner into an existing cluster.
Named leaders have gone quiet recently
Several of the assignees with the deepest historical filing records, including academic and corporate names, show zero filings in the most recent tracked year. Given the ~18-month publication lag, this may understate true activity, but it also signals no assignee has pulled decisively ahead in the current cycle.
| Assignee | Recent year | YoY |
|---|---|---|
| Soair Technology Corporation | 0 | — |
| CHAUDHARI ASHOK | 0 | — |
| Massachusetts Institute of Technology | 0 | — |
| Netherlands Organisation for Applied Scientific Research (TNO) | 0 | — |
| CHITKARA INNOVATION INCUBATOR FOUND | 0 | — |
| HART JOHN | 0 | — |
| DERKACS DANIEL | 0 | — |
| BITTNER ZACHARY | 0 | — |
Where to take this analysis
The dataset points to specific next steps depending on whether the goal is freedom-to-operate, portfolio building, or scouting collaborators.
Run a freedom-to-operate check on US filings
With 53 of 94 records receiving in the US, any commercialization plan targeting that market should map claims against the most-cited prior art before finalizing a device architecture.
Explore US filings in EurekaMap the H10K overlap in detail
The 18-record overlap with organic-semiconductor classification suggests hybrid perovskite-organic claims deserve their own sub-search rather than being folded into general tandem-cell prior art.
Search H10K overlap in EurekaTrack the Hart-Derkacs-Bittner cluster
This inventor group's repeated co-filings mark them as a reference point for current-matching and recombination-reduction claim language worth monitoring for new filings.
Follow this cluster in EurekaCommon questions on this landscape
This dataset tracks 94 patent families published between 2015 and mid-2026 that match claims on current matching, bandgap optimization or recombination reduction in tandem and multijunction solar cell structures. That figure reflects a targeted search string against specific IPC codes, so it undercounts the broader tandem solar cell literature, which spans many more classification codes. Because publication lags filing by roughly 18 months, the 2025-2026 counts in particular should be treated as provisional.
The dataset shows filing activity concentrated among a mix of named inventors, academic institutions and corporate assignees, with no single filer dominating the most recent year. A tightly linked inventor cluster around Hart John, Derkacs Daniel and Bittner Zachary shows the strongest repeated co-filing pattern in the corpus. Several historically active assignees, including academic institutions, show zero filings in the latest tracked year, which may reflect either reduced activity or the publication lag rather than an actual slowdown.
Filing activity rose from 4 records in 2017 to a peak of 16 in 2022, and has not exceeded that peak since, based on this dataset. That flat-to-declining trend after the midpoint of the tracked period suggests the core efficiency-enhancement mechanisms are increasingly well claimed rather than newly opening. New entrants should expect denser prior art on foundational current-matching and recombination-reduction claims than a simple year-over-year filing count would suggest.
The United States receives the largest share of filings in this dataset at 53 of 94 records, more than three times the next-largest offices, the EPO and India, at 14 each. WIPO PCT filings account for 8 records, indicating some applicants are still keeping international options open rather than committing to a single jurisdiction. Any freedom-to-operate analysis for a US-bound product should prioritize US filings first, then check EPO and India as secondary exposure.
US20210273127A1, assigned to King Fahd University of Petroleum and Minerals and published 2021-09-02, describes a perovskite-silicon tandem cell that uses surface modification of silicon to shift its optical band-edge properties, improving photon management and charge carrier extraction toward efficiencies above 28%. It is a representative example of the photon-management approach to current matching between sub-cells, one of the core technical routes tracked in this landscape. Anyone designing a perovskite-silicon stack with silicon-side surface modification for band-edge control should review this filing's claim scope directly rather than relying on the abstract alone.
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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.