Study of the Electronic Structure and Optical Properties of Rare Earth Luminescent Materials

Rare earth luminescent materials have attracted significant attention due to their wide-ranging applications in the field of optoelectronics. This study aims to delve into the electronic structure and optical properties of rare earth luminescent materials, with the goal of uncovering their importance in luminescence mechanisms and applications. Through theoretical calculations and experimental methods, we conducted in-depth analyses on materials composed of various rare earth elements. Regarding electronic structure, we utilized computational techniques such as density functional theory to investigate the band structure, valence state distribution, and electronic density of states of rare earth luminescent materials. The results indicate that the electronic structural differences among different rare earth elements notably influence their luminescence performance, providing crucial clues for explaining the luminescence mechanism. In terms of optical properties, we systematically examined the material’s optical behaviors through fluorescence spectroscopy, absorption spectroscopy, and other experimental approaches. We found that rare earth luminescent materials exhibit distinct absorption and emission characteristics at different wavelengths, closely related to the transition processes of their electronic energy levels. Furthermore, we studied the influence of varying doping concentrations and impurities on the material’s optical properties. Experimental outcomes reveal that appropriate doping can effectively regulate the emission intensity and wavelength, offering greater possibilities for material applications. In summary, this study comprehensively analyzed the electronic structure and optical properties of rare earth luminescent materials, providing deep insights into understanding their luminescence mechanisms and potential value in optoelectronic applications. In the future, these research findings will serve as crucial references for the technological advancement in fields such as LEDs, lasers, and bioimaging.

Researches on preparation and properties of polypropylene nonwovens containing rare earth luminous materials

Polypropylene composite nonwovens containing rare-earth strontium aluminates Sr Al2O4：Eu2＋,Dy3＋ and functional additives were fabricated by the spun-bonded technique.The optical properties, morphology and mechanical properties of the samples were characterized.Results from scanning electron microscopy photographs（SEM） indicated that the surface of the fiber was destroyed by the addition of rare earth luminescent materials lightly but the thickness of the fiber was uniform.Differential scanning calorimetry results showed that pure polypropylene has the double crystallization peak at 162.3 and 165.1 °C.Studies from X-ray diffraction showed that the nonwoven prepared with the luminescent materials contained the α-monoclinic crystal and β crystalline phase.Furthermore, the afterglow properties were tested, which showed that the afterglow curve of the luminous nonwoven was similar to that of strontium aluminate, and the intensity was more intensive than luminous nonwoven at the beginning.The nonwoven fabricated with the luminescent material did not affect the crystal lattice of the polymer making the materials have potential applications in fluorescent lamps and field emission displays（FEDs）.

Luminescence properties of Pr^(3+) and Bi^(3+) co-doped NaCaTiNbO_6 phosphor for red-LEDs

This paper investigates the photoluminescence properties of NaCaTiNbO6：Pr^3＋ and NaCaTiNbO6：Pr^3＋,Bi^3＋ phosphors. NaCaTiNbO6：Pr^3＋ and NaCaTiNbO6：Pr^3＋,Bi^3＋ powder were synthesized successfully by solid state reaction method. Phase purity was checked using X-ray powder diffractometry（XRD）. The excitation and emission spectra were recorded to elucidate the photoluminescence properties of NaCaTiNbO6：Pr^3＋ and NaCaTiNbO6：Pr^3＋,Bi^3＋. Furthermore,fluorescence lifetime measurements were performed. The excitation spectra of NaCaTiNbO6：Pr^3＋ show a main band centered at around 357 nm.The luminescence spectra of NaCaTiNbO6：Pr^3＋ exhibit a red emission peak at 615 nm from the ^1 D2→^3 H4 transition of Pr^3＋ ions. With the introduction of the Bi^3＋ ion into NaCaTiNbO6：Pr^3＋, the luminescence intensity is enhanced nearly two times. Meanwhile,the absorption band edge of NaCaTiNbO6：Pr^3＋ is shifted from 380 to 420 nm. Thus, this study shows that the red phosphor NaCaTiNbO6：Pr^3＋ incorporated with Bi^3＋ is advantageous for light-emitting diode applications.