GCL System Integration Technology Co., Ltd. (GCL SI) outlined its latest back-contact (BC) technology developments and product roadmap at the TaiyangNews Next-Gen PV Technologies Conference 2026, highlighting progress from its GPC 3.0 BC technology and commercial module portfolio to utility-scale BC modules and large-format perovskite-BC tandem technology.

Rojen Malachi, Technical Support Director, Europe, at GCL SI, presented the Company's latest developments in BC cell architecture, module design and manufacturing, as well as its plans to expand BC technology across distributed, utility-scale and next-generation tandem applications.

GPC 3.0 Advances BC Cell and Module Performance

GCL SI's proprietary BC cell architecture, Graphical Precise-doping Passivation Contact (GPC), has progressed to its latest generation, GPC 3.0. According to Malachi, the GPC 3.0 BC cell has achieved a conversion efficiency of 27.3%, supported by multilayer dielectric films to improve light absorption and the use of a fluidized-bed reactor (FBR) granular silicon.

The cell also incorporates damage-free laser-patterned passivation to reduce recombination losses, together with rear-contact metallization and fine-grid designs that support zero-busbar (0BB) interconnection. GCL SI is targeting a BC cell efficiency of approximately 28.9% by early 2028.

At the module level, GCL SI uses a full-screen design in which adjacent cells slightly overlap, increasing the active area and delivering a reported 10-12 W power gain. The company also uses rear-side interconnection and a low-temperature process designed to reduce thermal stress and wafer warping.

A direct-formed half-cell process is used in which wafers are divided before being processed into cells, rather than cutting finished cells and subsequently passivating their edges. According to Malachi, this approach reduces cutting losses and contributes approximately 5 W of additional module power.

To mitigate microcrack risks, GCL SI employs a linear, flat interconnection design rather than the conventional Z-shaped layout, thereby distributing mechanical stress more evenly and reducing stress concentrations at cell edges.

The GPC 3.0 platform also incorporates technology designed to improve module performance under partial shading. GCL SI's reverse-operating-curve modulation is designed to reduce hotspot temperatures and limit unnecessary bypass-diode activation. Under the company's test conditions, with approximately 15% of the module shaded, GPC modules maintained hotspot temperatures of 100°C to 130°C, compared with 160°C to 180°C for a standard module, while the design can recover more than 30% of the power, according to GCL SI.

The modules feature a temperature coefficient of -0.26%/°C, first-year degradation of 1%, and subsequent annual degradation of 0.35%. These characteristics are designed to support higher lifetime energy generation at elevated operating temperatures and over the long term during module operation.

Extending GPC 3.0 from European Rooftops to Utility-Scale Solar

GCL SI has extended its GPC 3.0 platform into its European distributed solar portfolio. Its full-black BC modules offer power ratings of 485 W to 500 W, primarily targeting residential applications. In contrast, the white-mesh variant, rated at 490-505 W, is designed for commercial and industrial rooftops.

The European BC modules have been in production for more than two months and feature 30-year product and performance warranties. GCL SI applies cell-level color sorting and automated module sorting to maintain consistent module appearance. The modules have also received IEC 61215 and IEC 61730 certifications.

The Company is now extending GPC 3.0 into utility-scale applications. Its upcoming large-format BC module uses a 2.3 × 1.1 m format with 66 cells and is expected to deliver power ratings ranging from 655 W to 690 W. Deliveries are planned to begin in Q4 2026.

Alongside its core BC portfolio, GCL SI also presented the SiRo anti-glare module, designed for applications near airports and highways. According to GCL SI, the module has received a Triple-A anti-glare assessment from TÜV Rheinland.

Advancing Toward Perovskite-BC Tandem Technology

Beyond crystalline-silicon BC technology, GCL SI is also advancing large-format perovskite-BC tandem technology as a next-generation pathway toward higher photovoltaic efficiency.

The Company's tandem module combines a perovskite-coated top glass with a BC silicon cell beneath it, allowing the two layers to absorb different portions of the solar spectrum. According to GCL SI, the perovskite layer accounts for approximately 75% of the module's power generation, while the BC silicon cell accounts for the remaining 25%.

The large-format tandem module measures approximately 2.4 × 1.15 m, offers power ratings of 655-720 W, and achieves an efficiency of approximately 26%. The module can also generate power from light entering its rear side, which GCL SI says is comparable to the rear-side generation of conventional bifacial silicon modules.

GCL SI is manufacturing the tandem modules in the first phase of its 1 GW perovskite production facility in Kunshan, near Shanghai. Manufacturing ramp-up and final product certification are expected to be completed by the end of 2026.

A Roadmap from Commercial BC to Next-Generation Tandem

GCL SI's latest technology developments demonstrate a BC roadmap spanning multiple stages of photovoltaic innovation—from high-efficiency BC cells and full-screen module architecture to distributed and utility-scale applications, and ultimately to perovskite-BC tandem technology.

Looking ahead, GCL SI will continue to advance BC technology by improving cell architecture, materials, interconnections, and manufacturing processes, while accelerating the commercialization of larger-format BC and tandem products for evolving global solar markets.