Study of synthesis temperature effect onβ-NaGdF₄: Yb³⁺, Er³⁺ upconversion luminescence efficiency and decay time...

Area of Science:

• Materials Science
• Nanotechnology
• Luminescence

Background:

• Upconversion nanoparticles (UCNPs) are vital for converting infrared to visible light, but practical applications require high luminescence intensity.
• Optimizing synthesis parameters is crucial for maximizing UCNP efficiency and performance in various applications.

Purpose of the Study:

• To investigate the effect of synthesis temperature on the upconversion luminescence efficiency and decay kinetics of β-NaGd$_{0.78}$Yb$_{0.20}$Er$_{0.02}$F$_{4}$ UCNPs.
• To analyze the relationship between synthesis temperature, nanoparticle characteristics, and luminescence properties.

Main Methods:

• Anhydrous solvothermal synthesis of β-NaGd$_{0.78}$Yb$_{0.20}$Er$_{0.02}$F$_{4}$ UCNPs with varying temperatures (290 °C-320 °C).
• Analysis of coherent scattering domain size and upconversion luminescence efficiency under 1 W cm⁻² excitation.
• Application of the maximum entropy method for processing luminescence decay kinetics.

Main Results:

• Synthesis temperature significantly influences UCNP luminescence efficiency and decay time.
• Coherent scattering domain size increased linearly with temperature (13.1-22.3 nm).
• Upconversion luminescence efficiency increased exponentially with temperature (0.02-0.10%).
• Two luminescence decay components (green) and one (red) were observed at lower temperatures, attributed to surface and core ion populations.
• Higher synthesis temperatures led to the disappearance of the surface component and increased decay time, indicating improved core luminescence and dopant distribution.

Conclusions:

• Synthesis temperature is a critical parameter for controlling the efficiency and luminescence decay of β-NaGdYbErF4 UCNPs.
• Optimizing synthesis temperature promotes a more uniform dopant distribution and enhances luminescence originating from the nanoparticle core.
• The findings provide insights for designing high-performance UCNPs for infrared-to-visible light conversion applications.