Spectrally Resolved Dynamics of Delayed Luminescence in Dense Scattering Media

Area of Science:

• Materials Science
• Optics
• Condensed Matter Physics

Background:

• Highly scattering media are crucial for applications like solar cells and photocatalysis.
• Understanding light-matter interactions in these materials is key for photonic device development.

Purpose of the Study:

• To investigate spectrally and time-resolved delayed luminescence (DL) in highly scattering rutile TiO2 films.
• To elucidate the influence of mesoscale structure on DL kinetics and spectral properties.

Main Methods:

• Measurements of spectrally and time-resolved delayed luminescence (DL).
• Analysis of non-exponential photon density decay and spectral composition evolution.
• Modeling of DL emission from dense scattering media.

Main Results:

• DL kinetics in TiO2 films exhibit complex, non-exponential decay.
• DL intensity and duration are significantly affected by scattering processes within the mesoscale structure.
• Observed DL lifetimes up to 6 seconds, linked to reabsorption processes and spectral redshift.

Conclusions:

• The mesoscale structure of scattering media critically influences delayed luminescence.
• A model is proposed to predict DL properties, aiding the design of advanced composite materials.
• Findings provide insights into light propagation and energy transfer in disordered photonic materials.