Erbium energy bridging upconversion mechanism studies on BAKL: Er3+/Yb3+ glass-ceramics and simultaneous enhancement of color purity of the green luminescence

Borate oxyfluoride glasses are transparent in the infra-red, ultra violet and visible regions and represent an ideal host matrix for optically active dopants. Due to their lower phonon energies compared...

Sensitization-initiated electron transfer via upconversion: mechanism and photocatalytic applications

A full picture of a new multi-photon excitation mechanism relying on sTTA upconversion is provided, together with selected photocatalytic applications. All mechanistic steps are investigated and the catalytically active species is observed directly.

Microstructure, transmittance and upconversion luminescence of Y2O3:Er3+ translucent ceramics

Y2O3:Er3+ translucent ceramics was fabricated with addition of La(OH)3 nanopowder as a sintering aid. The influence of La(OH)3 addition on the microstructure, transmittance and upconversion luminescence of Y2O3:Er3+ ceramics was investigated in detail. The results show that the ceramics sample with 5 mol % La(OH)3 additives exhibits finer microstructure with fewer pores and higher optical transmittance than others. It was proved that La(OH)3 additives could greatly reduce the porosity and improve the transparency of Y2O3:Er3+ ceramics. By using a 980 nm diode laser as a pumping source, the Y2O3:Er3+ ceramics gave bright visible upconversion luminescence, which was ascribed to the radiative transitions of 2H11/2,4S3/2 →4I15/2 and 4F9/2 →4I15/2 of Er3+ ions, respectively. The possible upconversion mechanism has been proposed accordingly.

Photon Upconversion in Lanthanide-Activated Inorganic Luminescent Materials

The growing demand for energy-efficient materials needs advancement in existing approaches. Photon upconversion is an effective way to overcome this issue. Novel upconverting materials show their potential in the advancement of energy conservation and lighting technology. In this contest, lanthanide-activated inorganic luminescent materials play a key role. The unique features of these materials like non-toxic nature, narrow multicolour emissions, long luminescence lifetime, high signal/noise ratio, and good chemical durability make them more promising. In this chapter, an overview of photon upconversion process in various lanthanide doped/codoped materials is given. Introductory idea about upconversion mechanism, criteria of material selection, novel synthesis roots, reports on upconversion-emitting materials, and emergent applications of these materials are presented.

Color change upconversion mechanism of Y-=SUB=-6-=/SUB=-O-=SUB=-5-=/SUB=-F-=SUB=-8-=/SUB=-:Er-=SUB=-3+-=/SUB=-/Yb-=SUP=-3+-=/SUP=- microtubes by using time-resolve spectra -=SUP=-*-=/SUP=-

The mechanism of the upconversion processes in Y_6O_5F_8: 2%Er^3+/ X %Yb^3+ ( X = 3, 10, 20) microtubes has been explored. The luminescent properties of the as prepared sample is investigated by utilizing up- /downconversion, decay and time resolve spectra. The results indicate that the red and green emission are clearly competitive depending on the Yb^3+ concentration. High Yb^3+ concentration induces the enhancement of the energy-back-transfer (EBT), process, which leads to the quenching of green emission and enhances the red emission. So it is possible to utilize the temporal evolutions of emission bands to deeply understand the color change UC mechanisms.