A direct observation of ultrafast energy transfer, charge trapping and thermal quenching in inorganic phosphors
Abstract
The functional properties of impurity-activated inorganic luminescent materials, or phosphors, used in lighting, sensors and radiation detection critically depend on their excited-state dynamics. These materials, and particularly persistent phosphors whose afterglow can last for hours after excitation ceases, are often regarded as systems dominated by slow emission processes. Yet, their excited-state dynamics are assumed to be governed by ultrafast events such as energy and charge transfer between dopants or nonradiative relaxation. Here, a combination of transient absorption and time-resolved luminescence spectroscopy is applied for the first time to capture the complete dynamics of these processes in benchmark SrAl ₂ O ₄ :Eu,(Dy), across an unprecedented time window from micro- down to picoseconds. It is found that nonradiative energy transfer between two distinct Eu ²⁺ centers occurs within several nanoseconds after excitation, accelerates with increasing temperature and reaches an intrinsic minimum transfer time of 5 ps at high temperatures. Charge transfer from the Eu ²⁺ activator to metastable trapping defects is roughly ten times faster than radiative decay, while, in contrast, reverse transfer following optical stimulation is much faster, taking place within 2–3 ps. Our study reveals that widely accessible pump–probe methods can resolve the ultrafast dynamics that govern seemingly slow phosphors, underscoring the need to bridge fast and slow timescales.
Related
- Atomic site engineering in garnet phosphors taming thermal quenching for high-power visible and NIR luminescence
- Vibrational Activation Triggers Ultrafast Excited State Intramolecular Proton Transfer in Single-Benzene Fluorophores
- Hot carrier extraction and ultrafast interfacial charge transfer in CsPbBr₃/carbon dot nanocomposites.
- Ultrafast interphase exciton funneling in alternating-cation 2D perovskites through Förster-type energy transfer.
- Bypassing Thermalization Losses through Ultrafast Interfacial Charge Transfer in Plasmonic Nanocavities for Water Oxidation.
BibTeX
@article{heggen2026direct,
title = {{A direct observation of ultrafast energy transfer, charge trapping and thermal quenching in inorganic phosphors}},
author = {David Van der Heggen and Korneel Molkens and Jonas J. Joos and Daniel Rytz and Lucas C. V. Rodrigues and Pieter Geiregat and Philippe F. Smet},
journal = {Light: Science \& Applications},
year = {2026},
month = oct,
doi = {10.1038/s41377-026-02433-z},
url = {https://www.nature.com/articles/s41377-026-02433-z},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - A direct observation of ultrafast energy transfer, charge trapping and thermal quenching in inorganic phosphors
AU - David Van der Heggen
AU - Korneel Molkens
AU - Jonas J. Joos
AU - Daniel Rytz
AU - Lucas C. V. Rodrigues
AU - Pieter Geiregat
AU - Philippe F. Smet
PY - 2026
DA - 2026/10/27
JO - Light: Science & Applications
DO - 10.1038/s41377-026-02433-z
UR - https://www.nature.com/articles/s41377-026-02433-z
AB - The functional properties of impurity-activated inorganic luminescent materials, or phosphors, used in lighting, sensors and radiation detection critically depend on their excited-state dynamics. These materials, and particularly persistent phosphors whose afterglow can last for hours after excitation ceases, are often regarded as systems dominated by slow emission processes. Yet, their excited-state dynamics are assumed to be governed by ultrafast events such as energy and charge transfer between dopants or nonradiative relaxation. Here, a combination of transient absorption and time-resolved luminescence spectroscopy is applied for the first time to capture the complete dynamics of these processes in benchmark SrAl ₂ O ₄ :Eu,(Dy), across an unprecedented time window from micro- down to picoseconds. It is found that nonradiative energy transfer between two distinct Eu ²⁺ centers occurs within several nanoseconds after excitation, accelerates with increasing temperature and reaches an intrinsic minimum transfer time of 5 ps at high temperatures. Charge transfer from the Eu ²⁺ activator to metastable trapping defects is roughly ten times faster than radiative decay, while, in contrast, reverse transfer following optical stimulation is much faster, taking place within 2–3 ps. Our study reveals that widely accessible pump–probe methods can resolve the ultrafast dynamics that govern seemingly slow phosphors, underscoring the need to bridge fast and slow timescales.
SN - 2047-7538
SN - 2095-5545
ER -