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arXiv · 1701.00930

Polarons Explain Luminescence Behavior of Colloidal Quantum Dots at Low Temperature

Meenakshi Khosla·Sravya Rao·Shilpi Gupta
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Abstract

Luminescence properties of colloidal quantum dots have found applications in imaging, light-sources, and displays. Despite wide interest, several experimental observations from these quantum dots, such as the short lifetime on the scale of microseconds and a zero-longitudinal optical phonon line in low-temperature photoluminescence spectrum, remain unexplained by existing models. Here we propose a model including the effect of solid-state environment on luminescence by capturing coherent and incoherent interactions of band-edge exciton with phonon modes. Our model predicts the 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.

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Meenakshi Khosla, Sravya Rao, Shilpi Gupta. 2017-01-04. Polarons Explain Luminescence Behavior of Colloidal Quantum Dots at Low Temperature. https://doi.org/10.1038/s41598-018-26678-w

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