Longi, a leading Chinese solar manufacturer, has made significant advancements in solar cell technology. In April 2025, the company unveiled a hybrid interdigitated back-contact (HIBC) solar cell boasting an impressive efficiency of 27.81%. This achievement establishes the device as the world’s most efficient silicon solar cell, certified by Germany’s Institute for Solar Energy Research Hamelin (ISFH).
Details of the Hybrid Interdigitated Back-Contact Solar Cell
The high-performance HIBC solar cell employs innovative technologies that enhance both optical management and carrier transport. Key features include:
- Passivated tunneling contacts and dielectric passivation layers.
- Utilization of both n-type and p-type contacts.
- A high-resistivity, half-cut M10 wafer with edge passivation.
- Indium tin oxide (ITO) layer for improved lateral transport.
- Optimized aluminum oxide (AlOx) and silicon nitride (SiNx) layers on the front surface to minimize recombination.
- Reduced phosphorus doping in the n-type polycrystalline silicon layer.
Scientific Contributions and Innovations
In their recent paper published in *Nature*, Longi’s research team, including President Li Zhenguo, details the mechanisms behind the cell’s design. Their innovations include:
- In Situ Passivated Edge Technology (iPET): A high–low temperature process combining diffusion and deposition for edge passivation during fabrication.
- 8-μm Deep Trenched Metal Fingers: These collect holes while preventing leakage between contacts.
- Laser-Induced Crystallization: A technique that enhances the a-Si layer’s properties while maintaining edge passivation.
Performance Metrics
The world-record efficiency of 27.81% corresponds to a cell with an active surface area of 133.63 cm². Several performance metrics were recorded, including:
| Metric | Value |
|---|---|
| Short-Circuit Current | 5,698 mA |
| Open-Circuit Voltage | 744.9 mV |
| Fill Factor | 87.55% |
Future Implications and Challenges
Longi envisions that these innovative techniques could be applied to the production of heterojunction (HJT) solar cells. However, challenges remain, particularly regarding contact resistivity. The company noted that the p-type contact shows 50% more resistive loss compared to the n-type contact, highlighting the need for ongoing improvements.
With its groundbreaking HIBC solar cell, Longi continues to push the boundaries of solar technology, setting new benchmarks for efficiency and performance in the industry. This progress not only reflects technological advancement but also a commitment to sustainable energy solutions.
