Optical and Magneto-Optical Properties of Donor-Bound Excitons in Vacancy-Engineered Colloidal Nanocrystals
| Autor: | Sergio Brovelli, Francesco Meinardi, Scott A. Crooker, Matteo L. Zaffalon, Marco Fanciulli, Andrea Camellini, Silvia Rotta Loria, Francesco Carulli, Fabrizio Moro, Valerio Pinchetti, Margherita Zavelani-Rossi |
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| Přispěvatelé: | Carulli, F, Pinchetti, V, Zaffalon, M, Camellini, A, Rotta Loria, S, Moro, F, Fanciulli, M, Zavelani-Rossi, M, Meinardi, F, Crooker, S, Brovelli, S |
| Rok vydání: | 2021 |
| Předmět: |
sulfur vacancy
nanocrystal quantum dot Letter Materials science Dopant Band gap Mechanical Engineering Exciton Exchange interaction Bioengineering General Chemistry Electron Condensed Matter Physics bound exciton Molecular physics electronic doping nanocrystal quantum dots magneto-optics Condensed Matter::Materials Science Vacancy defect General Materials Science spectro-electrochemistry Spin-flip Luminescence magneto-optic |
| Zdroj: | Nano Letters |
| ISSN: | 1530-6992 1530-6984 |
| DOI: | 10.1021/acs.nanolett.1c01818 |
| Popis: | Controlled insertion of electronic states within the band gap of semiconductor nanocrystals (NCs) is a powerful tool for tuning their physical properties. One compelling example is II-VI NCs incorporating heterovalent coinage metals in which hole capture produces acceptor-bound excitons. To date, the opposite donor-bound exciton scheme has not been realized because of the unavailability of suitable donor dopants. Here, we produce a model system for donor-bound excitons in CdSeS NCs engineered with sulfur vacancies (VS) that introduce a donor state below the conduction band (CB), resulting in long-lived intragap luminescence. VS-localized electrons are almost unaffected by trapping, and suppression of thermal quenching boosts the emission efficiency to 85%. Magneto-optical measurements indicate that the VS are not magnetically coupled to the NC bands and that the polarization properties are determined by the spin of the valence-band photohole, whose spin flip is massively slowed down due to suppressed exchange interaction with the donor-localized electron. |
| Databáze: | OpenAIRE |
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