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A research team led by Chinese polysilicon and solar module manufacturer Tongwei has developed a tunnel oxide passivated contact (TOPCon) solar cell that uses an emitter with higher sheet resistance to cut recombination losses, improve surface passivation and raise power conversion efficiency, according to pv magazine.
The work, published in Solar Energy Materials and Solar Cells, involved scientists from the School of Optoelectronic Science and Engineering at the University of Electronic Science and Technology of China and Chinese industrial equipment company Jiangsu Inspiray Equipment Co., Ltd.
The researchers noted that conventional TOPCon cells face a trade-off between low contact resistance and reduced carrier recombination in the boron-doped emitter. Their design addresses this by pairing heavily boron-doped regions beneath the metal contacts with lightly doped regions between the contacts. A non-destructive photoresist-based etching process was used to create the selective emitter structure, which reaches a sheet resistance of 1,600 ohms per square in non-contacted areas.
Corresponding author Xiajie Meng told pv magazine that this level is, to the team’s knowledge, the highest reported for TOPCon to date, and that the result confirms TOPCon remains highly competitive for commercial applications.
The team used scanning electron microscopy and 3D laser microscopy to examine etching depth and surface morphology, four-point probe measurements to determine sheet resistance in the lightly and heavily doped regions, and the transmission line method to evaluate contact resistivity. Doping profiles and junction depths were characterized through electrochemical capacitance-voltage measurements, while minority carrier lifetime and emitter recombination were assessed with quasi-steady-state photoconductance. Electron-beam-induced current measurements provided qualitative evidence of junction continuity, and photoluminescence imaging evaluated passivation quality under different illumination levels. Current-voltage measurements determined open-circuit voltage, short-circuit current density, fill factor, efficiency and series resistance, and Quokka3 simulations compared conventional uniform emitters, selective emitters and locally boron-doped finger structures.
The analysis showed that high-temperature oxidation lowered surface boron concentrations while increasing junction depth, helping suppress recombination and maintain effective metal contacts. Raising the sheet resistance of non-contacted emitter regions from 800 to 2,000 ohms per square significantly improved minority carrier lifetime and surface passivation, but gains became marginal beyond 1,600 ohms per square and doping uniformity deteriorated, making that value preferable for fabrication.
The selective emitter combined a sheet resistance of 450 ohms per square beneath the metal contacts with 1,600 ohms per square in non-contacted regions. This configuration raised average cell efficiency from 25.82% to 25.98%, an absolute improvement of 0.16 percentage points. Open-circuit voltage rose from 742.6 mV to 745.5 mV, and fill factor improved from 83.54% to 83.76%.
The optimized cell also achieved a certified efficiency of 26.03% with an open-circuit voltage of 746.5 mV, confirmed by Germany’s Solar Energy Research Hamelin (ISFH). The locally boron-doped finger structure improved passivation but suffered greater fill factor losses, reaching 83.34% versus 83.76% for the selective emitter, partly reflecting higher series resistance and potentially additional recombination.
Simulations examined contact width, grid pitch, finger width and wafer resistivity, indicating that a contacted-region width of about 200 micrometers offered the highest efficiency among the configurations studied. Reducing metal finger widths to 7 to 9 micrometers could allow a denser grid with a pitch of roughly 500 to 550 micrometers, potentially improving efficiency further.
Meng said simulations suggest that higher bulk resistivity wafers combined with more closely spaced front contacts could offer further gains for the locally boron-doped finger architecture, though experimental validation is still needed. The study, Meng added, demonstrates the potential of photoresist-based selective etching to produce emitters with exceptionally high sheet resistance in non-contacted areas without compromising contact quality, and the findings could help manufacturers refine emitter doping profiles and contact designs toward further efficiency gains and possible industrial adoption.
Interactive table based on the Store Companies dataset for this report.
This report is an independent strategic market study that provides a structured, commercially grounded analysis of the market for Solar Cells and Module in China. It is designed for battery and storage manufacturers, power-electronics suppliers, system integrators, EPC partners, developers, utilities, investors, and strategic entrants that need a clear view of deployment demand, technology positioning, manufacturing exposure, safety and qualification burden, project economics, and competitive structure.
The analytical framework is designed to work both for a single specialized storage or conversion component and for a broader renewable energy generation component, where market structure is shaped by chemistry, duration, project economics, system integration, safety requirements, route-to-market, and grid-interface logic rather than by one narrow customs heading alone. It defines Solar Cells and Module as Semiconductor devices that convert sunlight directly into electricity, manufactured as individual cells and assembled into modules (panels) for integration into solar power systems and examines the market through deployment use cases, buyer environments, upstream input dependencies, conversion and integration stages, qualification and safety requirements, pricing architecture, commercial channels, and country capability differences. Historical analysis typically covers 2012 to 2025, with forward-looking scenarios through 2035.
This report is designed to answer the questions that matter most to decision-makers evaluating an energy-storage, battery, renewable-integration, or power-conversion market.
At its core, this report explains how the market for Solar Cells and Module actually functions. It identifies where demand originates, how supply is organized, which technological and regulatory barriers influence adoption, and how value is distributed across the value chain. Rather than describing the market only in broad terms, the study breaks it into analytically meaningful layers: product scope, segmentation, end uses, customer types, production economics, outsourcing structure, country roles, and company archetypes.
The report is particularly useful in markets where buyers are highly specialized, suppliers differ significantly in technical depth and regulatory readiness, and the commercial landscape cannot be understood only through top-line market size figures. In this context, the study is designed not only to estimate the size of the market, but to explain why the market has that size, what drives its growth, which subsegments are the most attractive, and what it takes to compete successfully within it.
The report is based on an independent analytical methodology that combines deep secondary research, structured evidence review, market reconstruction, and multi-level triangulation. The methodology is designed to support products for which there is no single clean official dataset capturing the full market in a directly usable form.
The study typically uses the following evidence hierarchy:
The analytical framework is built around several linked layers.
First, a scope model defines what is included in the market and what is excluded, ensuring that adjacent products, downstream finished goods, unrelated instruments, or broader chemical categories do not distort the market boundary.
Second, a demand model reconstructs the market from the perspective of consuming sectors, workflow stages, and applications. Depending on the product, this may include Grid-connected solar farms, Commercial rooftop installations, Residential solar systems, Industrial self-consumption projects, Off-grid electrification, and Solar-powered consumer electronics and mobility across Power Generation (Utilities/IPPs), Commercial Real Estate, Industrial Manufacturing, Residential Construction, Telecommunications, and Public Infrastructure and Technology R&D and Pilot Lines, Capacity Planning and CAPEX Deployment, Supply Chain Sourcing and Qualification, Manufacturing Process Optimization, Quality Assurance and Certification, Sales Channel and Distribution Setup, and Project Design and System Integration. Demand is then allocated across end users, development stages, and geographic markets.
Third, a supply model evaluates how the market is served. This includes Polysilicon, Silicon Wafers (Mono Grown, Cast Multi), Solar Glass, Encapsulation Materials (EVA, POE), Backsheets, Frames (Aluminum), Silver Paste & Conductive Adhesives, and Specialty Gases and Chemicals, manufacturing technologies such as Passivated Emitter and Rear Cell (PERC), Tunnel Oxide Passivated Contact (TOPCon), Heterojunction Technology (HJT), Interdigitated Back Contact (IBC), Bifacial Module Design, Half-Cell and Shingled Cell Interconnection, and Advanced Module Encapsulation and Framing, quality control requirements, outsourcing, contract manufacturing, integration, and project-delivery participation, distribution structure, and supply-chain concentration risks.
Fourth, a country capability model maps where the market is consumed, where production is materially feasible, where manufacturing capability is limited or emerging, and which countries function primarily as innovation hubs, supply nodes, demand centers, or import-reliant markets.
Fifth, a pricing and economics layer evaluates price corridors, cost drivers, complexity premiums, outsourcing logic, margin structure, and switching barriers. This is especially relevant in markets where product grade, purity, customization, regulatory burden, or service model materially influence economics.
Finally, a competitive intelligence layer profiles the leading company types active in the market and explains how strategic roles differ across upstream material suppliers, component and controls providers, OEMs, storage-system integrators, EPC partners, project developers, and distribution or service channels.
This report covers the market for Solar Cells and Module in its commercially relevant and technologically meaningful form. The scope typically includes the product itself, its major product configurations or variants, the critical technologies used to produce or deliver it, the core input categories required for manufacturing, and the services directly associated with its commercial supply, quality control, or integration into end-user workflows.
Included within scope are the product forms, use cases, inputs, and services that are necessary to understand the actual addressable market around Solar Cells and Module. This usually includes:
Excluded from scope are categories that may be technologically adjacent but do not belong to the core economic market being measured. These usually include:
The exact inclusion and exclusion logic is always a critical part of the study, because the quality of the market estimate depends directly on disciplined scope boundaries.
The report provides focused coverage of the China market and positions China within the wider global energy-storage and renewable-integration industry structure.
The geographic analysis explains local deployment demand, domestic capability, import dependence, project-development relevance, safety and approval burden, and the country’s strategic role in the wider market.
This study is designed for strategic, commercial, operations, project-delivery, and investment users, including:
In many energy-transition, storage, power-conversion, and project-driven markets, official trade and production statistics are not sufficient on their own to describe the true market. Product boundaries may cut across multiple tariff codes, several product categories may be bundled into the same official classification, and a meaningful share of activity may take place through customized services, captive supply, platform relationships, or technically specialized channels that are not directly visible in standard statistical datasets.
For this reason, the report is designed as a modeled strategic market study. It uses official and public evidence wherever it is reliable and scope-compatible, but it does not force the market into a purely statistical framework when doing so would reduce analytical quality. Instead, it reconstructs the market through the logic of demand, supply, technology, country roles, and company behavior.
This makes the report particularly well suited to products that are innovation-intensive, technically differentiated, capacity-constrained, platform-dependent, or commercially structured around specialized buyer-supplier relationships rather than standardized commodity trade.
The report typically includes:
The result is a structured, publication-grade market intelligence document that combines quantitative modeling with commercial, technical, and strategic interpretation.
Energy-Storage Market Structure and Company Archetypes
Largest solar cell manufacturer by capacity
Vertically integrated from wafers to modules
Strong presence in utility-scale and distributed markets
Pioneer in high-efficiency modules
Listed on NASDAQ, operations based in China
Vertically integrated with global manufacturing
Known for high-power modules and overseas factories
Focus on distributed generation and utility projects
Brand Astronergy known for high-efficiency panels
Maxeon is spin-off, China HQ for manufacturing
Restructured, still active in manufacturing
Part of Hanwha Group, China-based factories
Part of Zhongli Group, exports globally
Strong in European and Asian markets
Restructured, still produces modules
Restructured, continues module production
Also produces cells for internal use
Subsidiary of TBEA, integrated supply chain
Restructured under Wuxi Industrial Development
Focus on high-efficiency PERC cells
Known for TOPCon and bifacial modules
Focus on high-efficiency back-contact cells
Active in distributed generation
Focus on off-grid and portable solar
Successor to original Suntech brand
Focus on high-efficiency cell production
Part of SAS group, Taiwan-linked but China HQ
Focus on next-gen high-efficiency cells
Listed on NYSE, China-based manufacturing
Focus on customized solar products
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