A research group led by Prof. WU Kaifeng from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has reported the efficient near-infrared photon upconversion sensitized by lead-free semiconductor nanocrystals, and demonstrated its novel application in solar synthesis.
The study was published in Nature Photonics on Feb. 6.
Upconversion of near-infrared photons to visible photons can boost the performance of photovoltaics, photoredox-catalysis and phototheranostics. Sensitized triplet-fusion is a promising means for photon upconversion.
However, current photosensitizers capable of near-infrared absorption often contain either precious or toxic elements, for example, palladium- or platinum-complexes and lead chalcogenide nanocrystals.
In this study, the researchers reported zinc-doped CuInSe 2 nanocrystals as a low-cost and environmentally-benign sensitizer for near-infrared-to-visible upconversion, which achieved external quantum efficiency of 16.7% for this spectral range.
This upconversion system was further merged with photoredox catalysis, enabling reductive dehalogenation, amine oxidation, carbon-oxygen bond formation and photopolymerization efficiently driven by near-infrared photons.
More importantly, thanks to the broadband light capturing of the near-infrared nanocrystals, these reactions were remarkably rapid under indoor sunlight, enabling, for example, polymerization of acrylates within just 30 seconds.
“Organic synthesis under sunlight, or solar synthesis, has been a century-long idea, which was pioneered by Ciamician et al . But organic chemists' vision has been limited to utilizing visible photons in sunlight," said Prof. WU. "Our study extends the reach of solar synthesis to both visible and near-infrared photons abundant in sunlight, which is poised to strongly boost this technology."
Nature Photonics
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Near-infrared photon upconversion and solar synthesis using lead-free nanocrystals
6-Feb-2023