Novel Interfacial Structure Achieves Highly Efficient, Stable Tandem Solar Cells

Why It Matters

The breakthrough demonstrates that high‑efficiency, long‑lasting tandem perovskite photovoltaics are moving toward commercial readiness, accelerating the clean‑energy transition.

Key Takeaways

• New SAM molecule CbzBT‑B enables 2D/3D heterojunction
• Voltage loss reduced, defect density minimized
• Tandem cell efficiency reaches 27.11%
• >95% efficiency retained after 700 hours
• Projected >90% efficiency after 1,800 hours

Pulse Analysis

Tandem solar cells, which stack a wide‑bandgap top absorber with a low‑bandgap bottom layer, are poised to surpass the efficiency ceiling of single‑junction photovoltaics. Perovskite materials offer exceptional light‑absorption properties, yet their commercial adoption has been hampered by interfacial instability and voltage losses that arise from uncontrolled ligand diffusion and defect formation. Researchers worldwide have pursued interface engineering strategies to mitigate these issues, recognizing that even modest reductions in recombination can translate into sizable gains in overall power conversion.

The Lingnan team’s solution centers on a custom‑designed SAM molecule, CbzBT‑B, whose sulfur atoms bind tightly to organic ligands, anchoring them at the perovskite interface. This creates a localized 2D/3D heterojunction that smooths film growth, lowers defect density, and aligns energy levels for more efficient charge extraction. Laboratory tests showed a record‑setting 27.11% efficiency for a perovskite‑organic tandem stack, while long‑term stability tests demonstrated over 95% efficiency retention after 700 hours and projected >90% after 1,800 hours—metrics that rival or exceed many silicon‑based tandem prototypes.

Beyond the laboratory, the advancement signals a pivotal step toward scaling tandem perovskite modules for the grid. Higher efficiencies reduce the area‑cost of solar farms, and the demonstrated durability addresses one of the primary barriers to market entry. As manufacturers seek to meet aggressive renewable‑energy targets, technologies that combine performance with reliability—such as this interfacial architecture—are likely to attract investment and accelerate the rollout of next‑generation solar panels, reinforcing the broader push toward a low‑carbon energy economy.