Effect of Ceramic Formation on the Emission of Eu3+ and Nd3+ Ions in Double Perovskites

Herein, the structure, morphology, as well as optical properties of the powder and ceramic samples of Ba2MgWO6 are presented. Powder samples were obtained by high temperature solid-state reaction, while, for the ceramics, the SPS technique under 50-MPa pressure was applied. The morphology of the investigated samples showed some agglomeration and grains with a submicron size of 490–492 µm. The theoretical density and relative density of ceramics were calculated using the Archimedes method. The influence of sample preparation on the position, shape, and character of the host, as well as dopants emission was investigated. Sample sintering enhances regular emission of WO6 groups causing a blue shift of Ba2MgWO6 emission. Nonetheless, under X-ray excitation, only the green emission of inversion WO6 group was detected. For the ceramic doped with Eu3+ ions, the emission of both host and dopant was detected. However, for the powder efficient host to activator energy, the transfer process occurred, and only the magnetic dipole emission of Eu3+ was detected. The intensity of Nd3+ ions of Ba2MgWO6 powder sample is five times higher than for the ceramic. The sintering process reduces inversion defects and creates a highly symmetrical site of neodymium ions. The emission of Ba2MgWO6:Nd3+ consists of transitions from the 4F3/2 excited level to the 4IJ multiplet states with the dominance of the 4F3/2→4I11/2 one. The spectroscopic quality parameter and branching ratio of Nd3+ emission are presented.

A numerical study of plasmon-induced enhancement of dipole emission by arrays of silver nanospheres and nanoprisms

Plasmon-induced enhancement of the photoluminescence (PL) intensity of quantum emitters by plasmon nanoparticles (PNPs) is a promising approach for the design and fabrication of PL hybrid materials with improved properties for biosensing and optoelectronics applications. This enhancement can be achieved through careful selection of such parameters as the PNP’s shape, material, size, the type of the medium around them, as well as the excitation and emission wavelengths of the emitter. Here, we simulated the nano-hybrid materials based on arrays of silver nanospheres, nanoprisms, and their combinations, located on polymer films with embedded dipole emitters. For these systems, the Purcell effect, as well as the excitation enhancement, transmittance, and absorption were evaluated. The results show the way to improve the PL properties of thin hybrid films by careful design of their composition using developed models.

Spontaneous emission of radiation

“Spontaneous emission of radiation” calculates the rate of spontaneous electric-dipole emission of a photon by an excited atom or molecule. The calculation proceeds by using basic quantum mechanics (i.e. not using the short cuts of Chapter 19); it uses quantum electrodynamics but is not, on that account, particularly difficult. A 2p–1s transition in hydrogen is used as exemplar; the radiation is elliptically polarized. The spectral line profile (lineshape function) is approximately Lorentzian, but has a high-frequency cut-off, needed to prevent the power radiated from diverging. A radiation-induced frequency shift is negligible. The width of the line profile agrees with the Einstein A-coefficient. A high-frequency cut-off is shown to apply similarly in the derivation of Golden Rule Number Two.