Bifacial Heterojunction Solar Cell Technology 2026
Bifacial Heterojunction Solar Cell Technology Landscape 2026
Bifacial HJT cells combine amorphous silicon passivation with dual-sided light capture for high open-circuit voltages and energy-yield gains. This dataset covers 70+ patent and literature records spanning 2008–2026.
Bifacial HJT Solar Cells: Architecture, Sub-Domains, and Dataset Scope
Bifacial heterojunction (HJT/SHJ) solar cells are built on n-type crystalline silicon substrates sandwiched between intrinsic and doped amorphous silicon thin films on both faces, terminated by transparent conductive oxide layers and metal grid electrodes. The defining feature is bilateral light reception, converting both direct irradiance and reflected albedo radiation.
The canonical architecture — n-type c-Si / i-a-Si:H / p-a-Si:H (front) + i-a-Si:H / n-a-Si:H (rear) / dual TCO / dual metal grid — appears across filings from Trina Solar, Tongwei Solar, Canadian Solar (Atlas CSI), and multiple university laboratories within this dataset, reflecting broad adoption of the symmetric stack as the baseline design.
Six key sub-domains are identified in this dataset: standard bifacial HJT cells with ITO/TCO; localized/selective-contact TCO-free designs; back-junction bifacial cells; IBC-SHJ bifacial cells; perovskite/HJT tandem bifacial cells; and alternative passivation and electrode materials including TiOx, SiOx/poly-Si, graphene, and nanocrystalline silicon layers.
In retrieved records, China accounts for more than 45 of approximately 55 identified patent filings, with the remainder split across the US (~7), EP (~3), DE (~2), WO (~1), and IN (~1). Trina Solar and Nanchang University each lead with 7 filings in this dataset, followed by Tongwei Solar with 5 filings in this dataset.
Innovation Phases and Technology Cluster Distribution in Retrieved Records
The bifacial HJT patent dataset spans four distinct innovation phases from 2008 to 2026, with a clear pivot from efficiency maximization toward cost reduction and next-generation tandem architectures after 2020.
Patent Filings by Technology Cluster — Bifacial HJT (Retrieved Records)
In this dataset, the standard bifacial a-Si:H/c-Si symmetric stack and localized/TCO-free selective-contact designs together account for the largest share of retrieved records, followed by IBC-SHJ, perovskite/HJT tandem, and hybrid/emerging architectures.
↗ Click bars to exploreBifacial HJT Filing Activity by Innovation Phase (Dataset Snapshot)
In this dataset, filing activity accelerated sharply in the 2020–2023 cost-optimization phase and continues into the 2024–2026 next-generation phase, reflecting a shift from architecture patents toward manufacturing process and tandem integration IP.
↗ Click bars to exploreKey Application Contexts for Bifacial HJT Solar Cells
Bifacial HJT cells are deployed across utility-scale ground-mount, BIPV, distributed/floating PV, and agrivoltaic contexts, with the technology’s low temperature coefficient and no LID/PID characteristics noted across multiple filings as advantages in variable-irradiance environments.
Utility-Scale Ground-Mount PV
Ground-mounted power plants are the primary commercial application in this dataset, with albedo contributions quantified at a 17% energy yield gain for a ground albedo factor of 0.3 versus monofacial IBC-SHJ cells. Fujian Jinshi Energy’s 2021 filings explicitly address bifacial module design and interconnection for power plant deployment. Albedo sources including grass, sand, snow, and concrete are described across multiple CN filings.
Utility PVBuilding-Integrated Photovoltaics (BIPV)
Industrial Technology Research Institute (US, 2011) identified the bifacial cell as a bifacial-type BIPV element due to grid electrodes on both faces. Anhui Huasheng New Energy (2026 CN) explicitly addresses single-face BIPV deployment, incorporating back-reflection structures to compensate for absent albedo gain in building envelope installations. This represents the most recent (2026) filing activity in this dataset.
BIPVFloating PV and Agrivoltaics
Multiple filings in this dataset describe albedo contributions from diverse reflective backgrounds — snow, green grass, white sand, and roofing shingles — positioning bifacial HJT cells for variable-irradiance environments such as floating PV arrays and agrivoltaic installations. The technology’s inherent no LID/PID characteristics and low temperature coefficient are cited as key advantages in these contexts. Fujian Jinshi Energy’s 2025 filing continues development for energy-constrained markets.
Distributed PVHigh-Efficiency Tandem PV Systems
Bifacial HJT cells serve as the bottom sub-cell in four-terminal perovskite/HJT tandem configurations, where literature reports efficiency exceeding 33% (normalized output) versus ~25% for series-connected tandem designs. A 2021 experimental study achieved >30% efficiency by exploiting spectral albedo on the bifacial rear face, exceeding the Shockley-Queisser limit for single-junction c-Si (~29.43%). Hanwha Solutions’ 2025 EP filing signals commercial-scale IP securitization in this architecture.
Tandem PVKey Patent Assignees in Bifacial HJT Solar Cells (Retrieved Records)
In this dataset, Trina Solar Co., Ltd. and Nanchang University each account for 7 filings in retrieved records — the highest counts observed — spanning foundational architecture through advanced TCO-free and selective-contact designs. Chinese assignees account for the overwhelming majority of filings in retrieved records, with non-Chinese activity concentrated in earlier foundational periods.
Top Assignees by Filing Count — Bifacial HJT (Dataset Snapshot)
↗ Click bars to exploreTrina Solar Co., Ltd.
Trina Solar is the most active patent filer in this dataset with 7 retrieved records spanning 2012 to 2025 (CN jurisdiction). Its portfolio covers foundational bifacial HJT cell architecture with tilted-groove front electrodes (2012) through advanced LECO-based dielectric contact designs (2024, 2025), with at least three active or pending CN patents targeting TCO elimination via laser-enhanced contact opening as of 2025.
China — CNNanchang University
Nanchang University holds 7 filings in this dataset — the highest count among academic institutions — concentrated in 2016–2019 (CN jurisdiction). Its program focuses on localized a-Si:H/c-Si heterojunction selective-contact designs that eliminate full-area ITO, and Si/TiOx heterojunction bifacial cells using wide-bandgap TiOx as an electron-selective front window layer, with multiple active CN patents across both sub-approaches.
China — CNNext-Generation Bifacial HJT: Five Emerging Technology Directions
The most recent filings (2024–2026) in this dataset signal a clear shift toward TCO elimination, perovskite/HJT tandem scale-up, nanocrystalline silicon doped layers, singlet-fission integration, and long-wavelength response enhancement as the dominant next-generation directions.
TCO Elimination via LECO Technology
The most prominent recent architectural shift in this dataset is the replacement of standard ITO/TCO layers with dielectric and anti-reflection layer stacks combined with laser-enhanced contact opening (LECO) to form localized metal-to-doped-layer contacts. This avoids ITO’s parasitic free-carrier absorption and its indium cost. Trina Solar has filed at least three active CN patents on this architecture (2024, February 2025, August 2025), all in active or pending status, suggesting imminent commercialization.
Perovskite/HJT Bifacial Tandem Scale-Up
Literature established >30% efficiency for bifacial 4-terminal perovskite/HJT tandems in 2021 by exploiting spectral albedo, exceeding the Shockley-Queisser limit for single-junction c-Si (~29.43%). Simulation results reported ~33% normalized efficiency for the bifacial tandem versus ~25% for series-connected tandem designs. Hanwha Solutions’ 2025 EP patent on a bifacial silicon/perovskite tandem signals that commercial entities outside China are now actively securing IP in this architecture.
Standard Bifacial HJT vs. Bifacial Perovskite/HJT Tandem
Click any row to explore further.
| Dimension | Standard Bifacial HJT | Bifacial Perovskite/HJT Tandem |
|---|---|---|
| Architecture | n-type c-Si / i-a-Si:H / doped a-Si:H / dual TCO / dual metal grid | Perovskite top sub-cell + bifacial c-Si HJT bottom sub-cell (4-terminal or monolithic) |
| Peak Efficiency (Literature) | ~26–27% (single-junction c-Si practical ceiling ~29.43% SQ limit) | >30% demonstrated (4-terminal, 2021); ~33% modeled (bifacial tandem) |
| Albedo / Rear-Side Gain | ~17% additional output at albedo 0.3 (IBC-SHJ model, 2019) | Rear bifacial face of HJT bottom cell independently captures albedo, decoupling current-matching constraints |
| TCO Requirement | Dual ITO/AZO standard; LECO-based TCO-free designs active in CN filings (Trina Solar, 2024–2025) | TCO required for HJT bottom cell; perovskite top cell uses transparent electrodes; long-wave TCO absorption is a critical loss mechanism |
| Key Assignees (Dataset) | Trina Solar, Nanchang University, Tongwei Solar, Fujian Jinshi Energy, Atlas CSI | Hanwha Solutions (EP, 2025); academic literature (2015, 2021) |
| Filing Activity (Dataset) | Dominant cluster in retrieved records; filings from 2012 through 2026 | Emerging cluster; Hanwha Solutions 2025 EP filing signals commercial IP entry |
| Fabrication Complexity | PECVD a-Si:H deposition; TCO sputtering; screen printing or plating of dual grids | Adds perovskite layer deposition and interface engineering; four-terminal design avoids current-matching but increases system complexity |
| Current Cost Focus | Silver paste reduction; ITO elimination; singulation optimization (Fujian Jinshi, Anhui Huasheng, Atlas CSI) | Perovskite stability and scalability; tandem interconnection; indium-free TCO alternatives |
Frequently Asked Questions: Bifacial Heterojunction Solar Cell Technology
The canonical architecture uses an n-type crystalline silicon (c-Si) wafer with bilateral intrinsic (i-a-Si:H) passivation layers, doped amorphous silicon (p-a-Si:H on the front emitter side and n-a-Si:H on the rear back-surface-field side), dual transparent conductive oxide (TCO) layers such as ITO or AZO, and screen-printed or plated metal grid electrodes on both faces. This structure enables light conversion on both the front direct-irradiance side and the rear albedo-reflecting side.
According to a 2019 modeling study on IBC-SHJ bifacial cells, an albedo factor of 0.3 (typical for surfaces like grass) delivers approximately 17% additional output compared to a monofacial IBC-SHJ cell. Albedo sources described in filings include grass, sand, snow, concrete, and roofing shingles.
A 2021 experimental study achieved greater than 30% efficiency for a bifacial 4-terminal perovskite/heterojunction silicon tandem by exploiting spectral albedo on the rear face, exceeding the Shockley-Queisser limit for single-junction c-Si (~29.43%). Simulation results for a bifacial tandem configuration report approximately 33% normalized efficiency, compared to approximately 25% for a series-connected tandem design.
Silver paste and ITO together represent the dominant non-silicon cost in HJT cells, according to multiple CN filings. ITO also causes parasitic free-carrier absorption, particularly harmful when HJT acts as the bottom cell in perovskite tandems. At least five distinct technical approaches to reducing or eliminating ITO/AZO are active in this dataset. Trina Solar’s LECO (laser-enhanced contact opening) approach, with three active or pending CN patents filed in 2024–2025, is the most prominent.
Trina Solar Co., Ltd. and Nanchang University each have 7 filings in this dataset — the highest counts. Tongwei Solar (Chengdu/Meishan) has 5 filings, while Fujian Jinshi Energy Co., Ltd. and LG Electronics Inc. each have 4 filings. Chinese assignees account for more than 45 of approximately 55 identified patent records with a jurisdiction in this dataset.
Beijing University of Technology filed a 2024 CN patent on inserting a singlet-fission (SF) layer into an HBC (heterojunction back-contact) cell to exploit high-energy photons via triplet exciton generation. The theoretical T1 exciton quantum yield for a singlet-fission material is 200%, targeting tandem-equivalent efficiency gains while avoiding the fabrication complexity of a full multi-layer tandem structure.
Data and insights on this page are based on a limited patent and literature dataset and are for reference only. Figures may not represent the complete technology landscape.