Tandem Solar Cell Architecture — PatSnap Eureka
Tandem Solar Cell Architecture: Breaking the Shockley-Queisser Efficiency Limit
Multi-junction photovoltaic stacks assign distinct spectral bands to sub-cells with matched bandgaps — directly attacking the thermodynamic ceiling that caps single-junction cells at approximately 33% efficiency. Explore the patent landscape driving this transformation.
Why the Shockley-Queisser Limit Demands a New Architecture
The Shockley-Queisser (S-Q) limit constrains single-junction solar cells because any photon with energy below the semiconductor bandgap is not absorbed, and any excess energy above the bandgap is lost as heat through thermalization. A single absorber material can only optimally harvest a narrow slice of the solar spectrum — setting the theoretical maximum efficiency at approximately 33%.
Tandem architecture directly addresses both loss mechanisms by stacking multiple sub-cells, each engineered with a distinct bandgap, so that the combined device absorbs photons across a much wider wavelength range. According to the International Energy Agency, next-generation photovoltaics require precisely this kind of spectral engineering to achieve meaningful efficiency gains beyond incumbent silicon technology.
Patent filings analyzed via PatSnap Eureka span multiple jurisdictions — France, Canada, Germany, Korea, and Australia — covering tandem architectures, heterojunction designs, and spectral absorption engineering. The most prominently recurring assignee is Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA), appearing in three closely related patents on simplified two-terminal tandem structures.
Dominant technical approaches across the dataset include perovskite-silicon heterojunction tandems, nano/microcrystalline silicon recombination zones, quantum dot spectral tuning, and multiband thin-film silicon-germanium stacks. Together, these reflect an industry-wide push to harvest broader portions of the solar spectrum. PatSnap's IP analytics platform enables R&D teams to map this landscape systematically.
Key Metrics from the Tandem Solar Cell Patent Landscape
All data points below are derived directly from the patent dataset analyzed via PatSnap Eureka, spanning 2017–2025 filings across five jurisdictions.
Patent Filings by Assignee: Tandem Solar Cell Architecture (2017–2025)
CEA dominates with 3 patents across France and Canada; Doral, Mac Science, and Choi Kyu-hyun each hold 1 filing in their respective jurisdictions.
Bandgap Complementarity in Perovskite-Silicon Tandem Cells
Perovskite (~1.6–1.8 eV) and silicon (~1.1 eV) bandgaps are engineered to address complementary spectral regions, together covering far more of the solar spectrum than either alone.
Recombination Zone Engineering: The Critical Bottleneck in Two-Terminal Tandems
Among all tandem configurations, the perovskite-on-silicon heterojunction tandem has attracted the most patent activity in this dataset. CEA's cluster of filings provides granular technical detail on the recombination zone — the layer that connects the two sub-cells and historically limited scaling of perovskite tandems.
Simplified Two-Terminal Tandem Structure
A two-terminal tandem photovoltaic structure built front to rear: a first silicon heterojunction cell (comprising amorphous silicon layers of defined conductivity types sandwiching a crystalline silicon substrate), a recombination zone containing nano-crystalline or mono-crystalline silicon, and a second sub-cell with an active layer made from a perovskite material. The recombination zone must enable efficient carrier recombination between the two junctions while maintaining low optical and electrical losses.
Nano/microcrystalline Si recombination zoneMulti-Jurisdictional Filing: Core IP Position
The French filings (2022 and 2025) describe identical structural configurations to the Canadian patent, signaling that CEA views this simplified recombination zone design as a core patentable contribution. By using nano- or microcrystalline silicon rather than indium tin oxide or other transparent conductive oxides in the recombination zone, the design avoids sputter damage to the perovskite layer and reduces parasitic absorption. The 2025 active status confirms ongoing commercial relevance.
Avoids sputter damage · Reduces parasitic absorptionTwo Structural Variants for Interface Optimization
The CEA patent specifies that the recombination zone may include either a first-conductivity-type layer in direct contact with the perovskite active layer, or a nano/microcrystalline silicon layer of the first conductivity type at that interface. These two structural variants are tuned to minimize interface recombination losses — a key source of efficiency degradation at the perovskite-silicon tunnel junction that has historically been a bottleneck in scaling perovskite tandems.
Two interface variants · Tunnel junction optimizationSimplification as a Scaling Strategy
The CEA approach simplifies manufacturing by reducing the number of specialized layers required at the perovskite-silicon tunnel junction. This is not merely an efficiency play — it is a manufacturability play. Fewer specialized deposition steps mean lower cost and higher yield as production scales, which is why the multi-jurisdictional filing strategy (France + Canada) signals CEA's intent to protect this approach commercially across major photovoltaic manufacturing regions. Learn more about PatSnap's approach to deep-tech IP analysis.
Fewer deposition steps · Lower cost at scaleQuantum Dot Spectral Tuning and Agrivoltaic Integration
The Doral Energy-Tech Ventures patent reveals a more complex multilayer approach that combines perovskite absorbers with quantum dot materials — and opens an entirely new application domain beyond grid power generation.
Quantum Confinement for Size-Tunable Bandgaps
The Doral patent explicitly exploits the quantum confinement effect in quantum dots to tune the bandgap through particle size control. Because quantum dot bandgaps are size-dependent, a single material system can be made to absorb at different wavelengths simply by varying particle dimensions. The composition, particle size, and particle concentration of each layer are engineered to precisely tune the wavelength range absorbed — making it possible to build multiple sub-cells from chemically similar materials, simplifying processing while still achieving spectral splitting.
Agrivoltaic Deployment: Matching Plant Absorption Spectra
The tandem structure is designed so that "the total transmittance of which is matched to the required absorption of the plants," enabling agrivoltaic deployment where the solar cell transmits specific wavelengths needed for plant photosynthesis while harvesting others for electricity. This dual-function design illustrates how tandem architecture, by enabling precise spectral selectivity, opens application spaces that are simply impossible for single-junction cells. The Food and Agriculture Organization has identified agrivoltaic integration as a key land-use efficiency strategy.
Key Players and Innovation Approaches in Tandem Solar Cell IP
| Assignee | Jurisdiction | Filing Year | Core Technical Approach | Status | Differentiator |
|---|---|---|---|---|---|
| CEA (Commissariat à l'Énergie Atomique) | France, Canada | 2022, 2025 | Simplified two-terminal perovskite-silicon heterojunction tandem; nano/microcrystalline Si recombination zone | Active Lead | Multi-jurisdictional filing; avoids sputter damage; reduces manufacturing complexity |
| Doral Energy-Tech Ventures L.P. | Germany | 2024 | Perovskite + quantum dot multilayer tandem; size-tunable bandgap via quantum confinement; agrivoltaic transmittance matching | Pending | Spectral transmittance matched to plant absorption; agrivoltaic dual-function design |
| 맥사이언스 (Mac Science) | Korea | 2023 | Tandem cell electroluminescence / photoluminescence imaging system; LED + IR camera + irradiation angle adjustment | Active | Quality control tooling for tandem manufacturing; supply chain positioning |
| Choi Kyu-hyun (individual inventor) | Korea | 2017 | Multiband Si-Ge thin-film; germanium alloying for bandgap grading; polysilicon rear layer; n-type front junction | Inactive | Earlier bandgap grading approach; monolithic thin-film multi-junction without discrete stacking |
Monitor Emerging Tandem Solar Cell Filings in Real Time
PatSnap Eureka tracks new filings across all jurisdictions as they publish. Set alerts for CEA, Doral, and emerging assignees in the perovskite-silicon space. Explore how R&D teams use PatSnap to stay ahead.
Dominant Technical Strategies Across the Tandem Solar Patent Dataset
Four distinct engineering approaches emerge from the patent landscape, each targeting the Shockley-Queisser limit from a different angle — from recombination zone design to quantum confinement and bandgap grading.
Four Technical Pathways Beyond the Shockley-Queisser Limit (Patent Dataset 2017–2025)
Each approach targets one or both primary loss mechanisms — sub-bandgap transmission and thermalization — using distinct material and structural strategies identified in the patent dataset.
Key Takeaways from the Tandem Solar Cell Patent Landscape
Tandem architecture directly targets the two primary loss mechanisms of the Shockley-Queisser limit — sub-bandgap transmission and thermalization — by assigning distinct spectral bands to sub-cells with matched bandgaps. The quantum dot and perovskite multilayer design from Doral Energy-Tech Ventures demonstrates this approach with fine-grained spectral control.
The recombination zone between sub-cells is the critical engineering challenge in two-terminal tandems. CEA's approach using nano/microcrystalline silicon avoids sputter damage and parasitic absorption, simplifying manufacturing relative to ITO-based alternatives. The consistency of this approach across three national filings (France 2022, France 2025, Canada 2022) underscores its commercial importance.
Perovskite-on-silicon heterojunction tandems dominate recent IP filings, reflecting the broader industry momentum: silicon provides manufacturing maturity and perovskite provides a tunable wide-bandgap absorber (~1.6–1.8 eV) that ideally complements silicon's ~1.1 eV bandgap for optimal spectral splitting. PatSnap's analytics platform maps this convergence across global jurisdictions.
Agrivoltaic integration — enabled by spectrally selective tandem transmittance — illustrates that exceeding S-Q limits has applications beyond grid power. The World Intellectual Property Organization has noted the growing intersection of agricultural technology and photovoltaic IP. Quantum dot size-tunable bandgaps represent a manufacturable path to higher sub-cell counts within chemically consistent material families. For enterprise IP teams, PatSnap's trust center details how proprietary patent data is handled securely.
Tandem Solar Cell Architecture — key questions answered
The Shockley-Queisser (S-Q) limit constrains single-junction solar cells because any photon with energy below the semiconductor bandgap is not absorbed, and any excess energy above the bandgap is lost as heat (thermalization). A single absorber material can only optimally harvest a narrow slice of the solar spectrum. The S-Q limit sets the theoretical maximum efficiency for a single-junction cell at approximately 33%.
Tandem architecture directly addresses both loss mechanisms by stacking multiple sub-cells, each engineered with a distinct bandgap, so that the combined device absorbs photons across a much wider wavelength range. Each layer absorbs a specific wavelength range and either transmits a portion of this range or transmits all other wavelengths, allowing the stack to cover far more of the solar spectrum than any single material could.
The recombination zone serves a dual function — it must enable efficient carrier recombination between the two junctions while maintaining low optical and electrical losses. CEA's approach uses nano- or microcrystalline silicon (rather than indium tin oxide or other transparent conductive oxides) in the recombination zone, which avoids sputter damage to the perovskite layer and reduces parasitic absorption.
Quantum dot bandgaps are size-dependent, so a single material system can be made to absorb at different wavelengths simply by varying particle dimensions. The composition, particle size, and particle concentration of each layer are engineered to precisely tune the wavelength range absorbed. This makes it possible to build multiple sub-cells from chemically similar materials, simplifying processing while still achieving spectral splitting.
The broader industry momentum shows perovskite providing a tunable wide-bandgap absorber (~1.6–1.8 eV) that ideally complements silicon's ~1.1 eV bandgap for optimal spectral splitting. This pairing allows the two sub-cells to address complementary portions of the solar spectrum.
Agrivoltaic integration refers to deploying solar cells in agricultural settings where the cell transmits specific wavelengths needed for plant photosynthesis while harvesting others for electricity. Tandem architecture enables this because precise spectral selectivity — tuning each sub-cell to absorb or transmit specific wavelength bands — allows the total transmittance of the tandem structure to be matched to the required absorption of the plants. This dual-function design illustrates how tandem architecture opens application spaces that are simply impossible for single-junction cells.
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References
- A tandem solar cell with selective spectral absorption and transmittance and its method — Doral Energy-Tech Ventures L.P., 2024 (DE)
- Simplified tandem structure for solar cells with two terminals — Commissariat à l'Énergie Atomique et aux Énergies Alternatives, 2022 (CA)
- Simplified structure of tandem solar cells with two terminals — Commissariat à l'Énergie Atomique et aux Énergies Alternatives, 2022 (FR)
- Simplified structure of tandem solar cells with two terminals — Commissariat à l'Énergie Atomique et aux Énergies Alternatives, 2025 (FR)
- Tandem solar cell electroluminescence imaging system — 맥사이언스 (Mac Science), 2023 (KR)
- Solar cell using multiband Si-Ge thin film silicon crystal and efficiency improvement method thereof — Choi Kyu-hyun, 2017 (KR)
- International Energy Agency (IEA) — Solar PV technology and efficiency analysis
- U.S. Department of Energy — Shockley-Queisser limit and next-generation photovoltaics
- World Intellectual Property Organization (WIPO) — Photovoltaic technology patent trends and agrivoltaic IP
- Food and Agriculture Organization of the United Nations (FAO) — Agrivoltaic integration and land-use efficiency
All data and statistics on this page are sourced from the references above and from PatSnap's proprietary innovation intelligence platform.
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