Longi, a Chinese solar module maker, published new details in a scientific paper about its 27.81% efficient hybrid interdigitated back-contact (HIBC) silicon solar cell. The cell, unveiled in April 2025, is based on passivated tunneling contacts and dielectric passivation layers, and incorporates both n-type and p-type contacts. The study, titled “Silicon solar cells with hybrid back contacts,” appears in Nature and details design choices that balance optical management with carrier transport efficiency.
[1][5]The April 2025 announcement, supported by certification from Germany’s Institute for Solar Energy Research Hamelin (ISFH), described the device as achieving the world’s highest silicon solar cell efficiency at the time. A company spokesperson, quoted to pv magazine, highlighted breakthroughs in cell architecture and material systems that contributed to improved optical management and carrier transport, though without disclosing further specifics.
[7][1]In the new paper, the Longi research team—including Li Zhenguo, the president and founder—explains that the cell’s performance stems from the combination of passivated tunneling contacts, dielectric passivation layers, and both n-type and p-type contacts. The reported metrics include a 27.81% efficiency on a cell with an active surface of 133.63 cm², a short-circuit current of 5,698 mA, an open-circuit voltage of 744.9 mV, and a fill factor of 87.55%. These figures underscore the dual emphasis on optical management and electronic transport.
[5][1]Context from industry reporting confirms that the result was validated by ISFH and marked a record for silicon solar cells at that time. The April claim positioned Longi at the forefront of silicon cell efficiency, ahead of prior thresholds, with the team stressing that optimization involved carefully balancing passivation quality, conductivity, and laser processing parameters.
[1][5]“By redesigning both the cell architecture and material systems, we achieved simultaneous breakthroughs in optical management and carrier transport efficiency,” a Longi spokesperson told pv magazine at the time.
Summary of the core technical approach: a full-structure HIBC cell built on passivated tunneling contacts and dielectric passivation layers, employing both n-type and p-type contacts to maximize carrier collection and minimize recombination losses. The achieved metrics demonstrate the impact of integrated optical and electrical design on overall efficiency.
[5][1]Author’s note: Longi’s reported innovations reflect a strategic blend of advanced passivation, contact engineering, and optical management, signaling a significant step forward for silicon-based solar cells. The paper’s publication reinforces the company’s role in pushing silicon cell performance into new territory while maintaining a focus on scalable manufacturing principles.
[1]Author summary (120–200 characters): Longi presents a 27.81% silicon solar cell using passivated tunneling contacts and dielectric layers with dual n/p-type contacts, validated by ISFH, marking a new efficiency benchmark.
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