Polarons Explain Luminescence Behavior of Colloidal Quantum Dots at Low Temperature

Meenakshi Khosla, Sravya Rao, Shilpi Gupta

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Luminescence properties of colloidal quantum dots have found applications in imaging, displays, light-emitting diodes and lasers, and single photon sources. Despite wide interest, several experimental observations in low-temperature photoluminescence of these quantum dots, such as the short lifetime on the scale of microseconds and a zero-longitudinal optical phonon line in spectrum, both attributed to a dark exciton in literature, remain unexplained by existing models. Here we propose a theoretical model including the effect of solid-state environment on luminescence. The model captures both coherent and incoherent interactions of band-edge exciton with phonon modes. Our model predicts formation of dressed states by coupling of the exciton with a confined acoustic phonon mode, and explains the short lifetime and the presence of the zero-longitudinal optical phonon line in the spectrum. Accounting for the interaction of the exciton with bulk phonon modes, the model also explains the experimentally observed temperature-dependence of the photoluminescence decay dynamics and temperature-dependence of the photoluminescence spectrum.

Original languageEnglish
Article number8385
JournalScientific Reports
Issue number1
StatePublished - 1 Dec 2018
Externally publishedYes

ASJC Scopus subject areas

  • General


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