⚡ Record Efficiency in HJT / Passivated Solar Cells: Pushing the Limits
1. Introduction: What Are HJT / Passivated Solar Cells?
Heterojunction Technology (HJT) solar cells combine crystalline silicon wafers with thin layers of amorphous or microcrystalline silicon to capture sunlight more efficiently. Passivation techniques are used to reduce recombination losses at surfaces and interfaces. These features give HJT cells advantages like:
- Higher open-circuit voltage (Voc)
- Better low-light & temperature performance
- Reduced degradation over time
2. Recent Milestones & Records
Here are some of the recent record-breaking achievements in HJT / passivated solar cell tech:
| Company / Institution | Breakthrough / Record | Efficiency & Key Details |
|---|---|---|
| Trina Solar | New record for n-type fully passivated HJT solar cell | 27.08%, verified on a large (210mm×105mm) half-cut n-type silicon wafer. Improvements came through full rear-side passivation, RF doping, ultra-fine printing. |
| LONGi | Multiple recent records in HJT | Achieved 25.82%, then further 26.30% in HJT cell efficiency. Improvements involved better window layer, intrinsic layer structure, and reduced contact resistance. |
| Huasun | Mass production HJT cells reaching high average efficiency | G12R / G12 HJT cells averaged ~26.0-26.5%, with peak values around 26.50% under full production conditions. |
3. What Enabled These Improvements
A combination of material, process, and design innovations has driven the efficiency gains:
- Improved surface/interface passivation: Minimizing recombination at the wafer surface and contacts, with better intrinsic-layer designs and dual passivation techniques.
- Optimized window / conductive layers: Lowering optical losses, improving transparency, optimizing thickness and doping.
- Better contact design & metallization: More fingers, finer lines, multiple busbars, or even zero busbar designs to reduce shading and resistive losses.
- Larger cell formats / scaling: Moving from lab-scale to full-size wafers while maintaining high performance, ensuring uniformity in deposition and texture across large areas.
4. Impacts: Market & Cost Implications
- Lower levelized cost of electricity (LCOE): Higher efficiency means more power per unit area, reducing BOS, mounting, land usage, and cooling costs.
- Better performance in harsh / variable conditions: HJT cells retain performance better at high temperatures and low light, increasing energy yield per installed watt.
- Faster deployment & ROI: Higher efficiency modules are more cost-effective when roof or land space is limited.
- Competition: HJT competes with TOPCon, perovskite tandems, and other high-efficiency technologies, each balancing cost, durability, and scalability.
5. Challenges Remaining
- Cost & complexity: Advanced passivation layers and contact designs add manufacturing challenges and cost.
- Materials & supply chain: Transparent conductive oxides, silver, and donor materials must remain affordable and sustainable.
- Long-term reliability: Passivated surfaces must endure decades of exposure to moisture, UV, and thermal cycles.
- Manufacturability at scale: Translating lab-scale records to mass production while preserving quality remains critical.
6. The Road Ahead
- More HJT cells crossing into the 28–30+% range in labs and pilot lines.
- Perovskite-on-HJT tandems to push beyond single-junction limits.
- Rising module efficiencies in real-world field systems.
- Lower costs through design refinements, economies of scale, and new materials.
7. Conclusion
Record achievements in HJT and passivated contact solar cells represent one of the most promising paths forward in photovoltaic technology. As efficiencies inch higher and mass production scales up, HJT could become a dominant solution for next-gen solar panels. These milestones are not just lab curiosities—they are signs of a near future where clean energy is more powerful, more efficient, and more affordable than ever.
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