Solar Cells Beat the 100% Rule with a New Energy Trick

A collaboration between researchers from Kyushu University (Japan) and Johannes Gutenberg University Mainz (Germany) has achieved a groundbreaking solar‑cell efficiency of roughly 130 %, surpassing the traditional Shockley–Queisser limit.

How It Works

• Singlet fission: A single high‑energy photon is split into two lower‑energy excitations, potentially doubling usable energy.
• Molybdenum complex: A specially engineered metal complex flips the spin of an electron when it absorbs or emits near‑infrared light. This allows it to capture the triplet excitons generated by singlet fission.
• Energy‑level tuning: By precisely adjusting the complex’s energy levels, researchers minimized losses from Förster resonance energy transfer (FRET), achieving quantum yields of about 1.3 excitations per absorbed photon.

Experimental Highlights

• Tested in solution with tetracene, a well‑known fission material.
• Demonstrated an efficiency of ~130 %, meaning more energy carriers are produced than photons absorbed—an impossibility for conventional cells.

Implications

• Solar technology: Potential to push beyond current efficiency ceilings and create high‑efficiency panels that fully exploit every photon.
• Other fields: Could benefit LEDs and quantum information devices where efficient energy transfer is critical.

Next Steps

• Stabilize materials in solid films.
• Integrate with existing solar‑cell architectures.

If these challenges are met, we may soon witness a new class of ultra‑efficient solar panels that harness light more completely than ever before.