Predicting the afterglow duration in persistent phosphors: a validated approach to derive trap depth distributions

Area of Science:

• Materials Science
• Solid State Physics
• Luminescence

Background:

• Persistent phosphors store and release energy, acting as optical batteries for applications in signage, dosimetry, and imaging.
• Understanding defect sites and trapping mechanisms is crucial for optimizing persistent phosphor properties.
• LiGa5O8:Cr3+ (LGO:Cr) is a near-infrared (NIR) emitting persistent phosphor with potential applications.

Purpose of the Study:

• To investigate the thermoluminescence and afterglow properties of LGO:Cr.
• To present a generalizable method for deriving trap depth distributions in persistent luminescent materials.
• To establish a rigorous approach for determining trapping parameters in storage phosphors.

Main Methods:

• Utilized the Tstop-Tmax method combined with initial rise analysis to identify trap distributions.
• Employed computerized glow curve fitting for simultaneous analysis of experimental data.
• Applied a model system (LGO:Cr) to demonstrate the methodology.

Main Results:

• Identified a broad distribution of trapping states within the LGO:Cr phosphor.
• Successfully extracted a consistent set of trapping parameters using the developed methods.
• Demonstrated that the model parameters accurately describe both thermoluminescence and afterglow data.

Conclusions:

• The developed methodology reliably determines trap structure and parameters in persistent phosphors.
• The approach is applicable to various persistent and storage phosphors.
• Accurate trapping parameters enable prediction of afterglow and storage behavior under different conditions.