Temperature-Dependent Spectroscopy of Cr3+:YGG Nanophosphors with Multisite Emission

TL;DR

This study investigates how temperature affects the luminescence of Cr3+:YGG nanocrystals, revealing concentration-dependent spectral shifts and multisite emission behavior relevant for tunable phosphor applications.

Contribution

It demonstrates the synthesis of Cr3+:YGG nanocrystals with multisite emission and analyzes temperature-dependent spectral changes linked to concentration and energy transfer.

Findings

Redshift of emission with increased Cr3+ concentration at 80K

Similarity of emission spectra at room temperature across samples

Increase in crystal field strength with Cr3+ concentration

Abstract

An important feature of Cr3+ is the ability to tune the absorption and emission spectra by changing the host. However, in some cases, different emission spectra can be detected in samples with similar Racah parameters. The present paper reports changes in the luminescence properties of Cr3+:YGG nanocrystals. Cr3+:YGG nanocrystals were synthesized by a modified Pechini method to obtain nanocrystals containing two fractions of Cr3+:YGG nanocrystals with different lattice parameters and crystalline sizes. The increase in the concentration of Cr3+ ions leads to a redshift of the 4T2g emission from 750 nm to 850 nm for luminescence spectra measured at 80K. In contrast, room temperature luminescence spectra showed similarity in the shape of the emission spectra. The calculated crystal field strength was found to increase with the concentration of Cr3+ ions, so the detected patterns in low-temperature luminescence spectra were explained by energy transfer chain processes.