Singlet Fission Via a Molybdenum-Based Near-Infrared Light-Emitting Spin-Flip Emitter Shows Promise for Breaking the Shockley–Queisser Limit of Solar Cell Efficiency

  

     Japanese researchers have devised a means to capture extra energy from sunlight using a metal-based system that reduces heat losses during conversion. The method involves a chemical structure known as a spin-flip emitter made of molybdenum, which captures multiplied energy created during a process called singlet fission. This is an important discovery for potentially improving solar cell efficiency by up to 130%.

     When solar cells convert sunlight into electricity, they only utilize some of the available energy. There is a limit to how much of the available energy can be utilized due to “a mismatch between photon energies and how semiconductors respond,” as noted below. This creates a solar cell efficiency limit known as the Shockley–Queisser limit. The new research is one of two main methods being explored to break that limit.

“One long-known ceiling comes from the mismatch between photon energies and how semiconductors respond, which means some photons fail to trigger electrons while others lose excess energy as heat.”

“This efficiency cap, known as the Shockley–Queisser limit, has pushed researchers to explore methods that reuse lost energy instead of letting it dissipate.”

The Shockley–Queisser Limit and the Implications of Breaking It

     Wikipedia explains the Shockley–Queisser limit as follows:

“The Shockley–Queisser limit is the maximum theoretical efficiency of a solar cell using a single p–n junction to collect power from the cell where the only loss mechanism is radiative recombination in the solar cell. It was first calculated by William Shockley and Hans-Joachim Queisser at Shockley Semiconductor in 1961, giving a maximum efficiency of 30% at 1.1 eV. The limit is one of the most fundamental to solar energy production with photovoltaic cells, and is one of the field's most important contributions.”

     Note that it is about 30%. That means if efficiency improves by 130%, then the efficiency of the solar cell would increase from 30% to 69%. Such an efficiency increase would be truly groundbreaking, and a new solar revolution would ensue. However, this is still in the research phase, and more breakthroughs will be required to initiate commercialization.

Summary by Wayne Williams for TechRadar Pro

     Wayne Williams of TechRadar Pro does a good job of explaining this research breakthrough. I found the abstract of the paper, which was published in the Journal of the American Chemical Society, but much of the explanation in it went over my head, so his explanation is a useful summary.

“Singlet fission, described by the researchers as a “dream technology” for light conversion, plays a central role in the experiment because it allows one high-energy excitation to split into two lower-energy ones, theoretically doubling the number of usable energy carriers.”

“Capturing those duplicated excitons has been the harder problem, since competing energy transfer processes can redirect energy before it becomes useful.”

“The team addressed that bottleneck by pairing singlet fission materials with a molybdenum-based near-infrared spin-flip emitter tuned to absorb specific triplet energy states.”

“The energy can be easily ‘stolen’ by a mechanism called Förster resonance energy transfer (FRET) before multiplication occurs,” said Sasaki. “We therefore needed an energy acceptor that selectively captures the multiplied triplet excitons after fission.”

“Experiments using tetracene-based materials in solution produced quantum yields ranging from just over 110% to about 130%, meaning more energy carriers were generated than incoming photons absorbed under laboratory conditions.”

“Results remain limited to solution testing rather than full solar devices, meaning practical application still depends on translating the chemistry into solid materials compatible with working panels.”

“Future work will focus on combining these materials into solid-state systems where energy transfer efficiency can be tested under conditions closer to real solar cell operation.”

 

 

References:

 

Japanese researchers develop spin-flip material to increase solar panel efficiency by up to 130%. Wayne Williams. TechRadar Pro. May 3, 2026. Japanese researchers develop spin-flip material to increase solar panel efficiency by up to 130%

Exploring Spin-State Selective Harvesting Pathways from Singlet Fission Dimers to a Near-Infrared-Emissive Spin-Flip Emitter. Percy Gonzalo Sifuentes, Samanamud Adrian, Sauer Aki, Masaoka Yuta, Sawada Yuya, WatanabeIlias Papadopoulos, Katja Heinze, Yoichi Sasaki, and Nobuo Kimizuka. Journal of the American Chemical Society. Vol 148/Issue 13. March 25, 2026. Exploring Spin-State Selective Harvesting Pathways from Singlet Fission Dimers to a Near-Infrared-Emissive Spin-Flip Emitter | Journal of the American Chemical Society

Shockley–Queisser limit. Wikipedia. Shockley–Queisser limit - Wikipedia

Solar-cell efficiency. Wikipedia. Solar-cell efficiency - Wikipedia