Enhanced red emission of doped lanthanide ions in Gd2O3: In the perspective of phase transformation

Exploring the relationship between luminescence and the structure and morphology of rare-earth-doped host materials is essential for their expanded use in various fields. The present work investigates the luminescent properties of rare-earth ions within two structural frameworks: cubic and monoclinic Gd2O3 systems. The phase transformation of the Gd2O3 systems was determined via X-ray powder diffraction with increasing sintering temperatures. The results indicated that doping the monoclinic system with rare-earth ions resulted in significantly enhanced red emissions; in contrast, this outcome was not observed for the cubic framework. The specific crystal structure of monoclinic phase also played a key role in determining the tunable emissions as it enhanced the energy-back-transfer and cross-relaxation processes within energy transfer in ladder-like sequence. The distinguished spectral profile of rare-earth ions doped into monoclinic Gd2O3 systems leads to good potential candidates for plant growth LED applications.