Rise and Decay of Photoluminescence in Upconverting Lanthanide-Doped Nanocrystals
OPEN ACCESS
Loading...
Author / Producer
Date
2024-10-15
Publication Type
Journal Article
ETH Bibliography
yes
Citations
Altmetric
OPEN ACCESS
Data
Rights / License
Abstract
Nanocrystals (NCs) doped with lanthanides are capable of efficient photon upconversion, i.e., absorbing long-wavelength light and emitting shorter-wavelength light. The internal processes that enable upconversion are a complex network of electronic transitions within and energy transfer between dopant centers. In this work, we study the rise and decay dynamics of upconversion emission from β-NaYF₄ NCs codoped with Er³⁺ and Yb³⁺. The rise dynamics of the red and green upconverted emissions are nonlinear, reflecting the nonlinear nature of upconversion and revealing the mechanisms that populate the emitting states. The excited-state decay dynamics are nonexponential. We unravel the underlying decay pathways using photonic experiments. These reveal the contributions of different upconversion pathways visually, as each pathway exhibits a distinct response to systematic variation of the local density of optical states. Moreover, the effect of the local density of optical states on core-only NCs is qualitatively different from core–shell NCs. This is due to the different balance between feeding and decay of the electronic levels that produce upconverted emission. The understanding of the upconversion dynamics provided here could lead to better imaging and sensing methods relying on upconversion lifetimes or guide the rational optimization of the dopant concentrations for brighter upconversion.
Permanent link
Publication status
published
External links
Editor
Book title
Journal / series
Volume
18 (41)
Pages / Article No.
28325 - 28334
Publisher
American Chemical Society
Event
Edition / version
Methods
Software
Geographic location
Date collected
Date created
Subject
Infrared Light; Ions; Lasers; Luminescence; Power; Colloidal Nanocrystals; Upconversion; Lanthanide Ions; Excited-State Dynamics; Local Density of Optical States