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Direct observation of triplet energy transfer from semiconductor nanocrystals
Ist Teil von
Science (American Association for the Advancement of Science), 2016-01, Vol.351 (6271), p.369-372
Ort / Verlag
United States: American Association for the Advancement of Science
Erscheinungsjahr
2016
Link zum Volltext
Quelle
American Association for the Advancement of Science
Beschreibungen/Notizen
Triplet excitons are pervasive in both organic and inorganic semiconductors but generally remain confined to the material in which they originate. We demonstrated by transient absorption spectroscopy that cadmium selenide semiconductor nanoparticles, selectively excited by green light, engage in interfacial Dexter-like triplet-triplet energy transfer with surfacr-anchored polyaromatic carboxylic acid acceptors, extending the excited-state lifetime by six orders of magnitude. Net triplet energy transfer also occurs from surface acceptors to freely diffusing molecular solutes, further extending the lifetime while sensitizing singlet oxygen in an aerated solution. The successful translation of triplet excitons from semiconductor nanoparticles to the bulk solution implies that such materials are generally effective surrogates for molecular triplets. The nanoparticles could thereby potentially sensitize a range of chemical transformations that are relevant for fields as diverse as optoelectronics, solar energy conversion, and photobiology.