Blue–Green Emission in Terbium‐Doped Alumina (Tb:Al₂O₃) Transparent Ceramics

Abstract

is one of the most versatile ceramics, utilized in an amazing range of structural and optical applications. In fact, chromium-doped single crystal Al 2 O 3 was the basis for the fi rst laser. Today, most photoluminescent (PL) materials rely on rare earth (RE) rather than transition-metal dopants because RE doping produces greater effi ciencies and lower lasing thresholds. RE-doped alumina could provide an extremely versatile PL ceramic, opening the door for a host of new applications and devices. However, producing a transparent RE:Al 2 O 3 suitable for PL applications is a major challenge due to the very low equilibrium solubility of RE ( ∼ 10 −3 %) in Al 2 O 3 in addition to alumina's optical anisotropy. A method is presented here to successfully incorporate Tb 3+ ions up to a concentration of 0.5 at% into a dense alumina matrix, achieving a transparent light-emitting ceramic. Sub-micrometer alumina and nanometric RE oxide powders are simultaneously densifi ed and reacted using current-activated, pressure-assisted densifi cation (CAPAD), often called spark plasma sintering (SPS). These doped ceramics have a high transmission ( ∼ 75% at 800 nm) and display PL peaks centered at 485 nm and 543 nm, characteristic of Tb 3+ emission. Additionally, the luminescent lifetimes are long and compare favorably with lifetimes of other laser ceramics. The high transparencies and PL properties of these ceramics have exciting prospects for high energy laser technology.

Plasmonically Enhanced Optical Characteristics From Europium Organometallic Complex

“…The inset figure displays lifetime values of the samples, in which the lifetime is the time required for the initial intensity to decrease by a factor of 1/e [21]. As confirmed in the inset figure of Fig.…”

Broadband white light emission from Ce:AlN ceramics: High thermal conductivity down-converters for LED and laser-driven solid state lighting

“…[13][14][15] Of particular importance are the high heating and cooling rates that allow for higher than equilibrium doping in ceramics. 16,17 The inset in the top left corner of Figure 1 is a picture of a CAPAD processed Ce:AlN ceramic on top of a commercial UV-LED (365 nm, LED World). The light emitted is white, demonstrating a proof of the concept that Ce:AlN is viable for SSL applications.…”

Structural Effects of Lanthanide Dopants on Alumina

“…Due to the large size of the Ln-ions compared to Al 3+ (0.054 nm for Al 3+ and 0.103 nm → 0.0861 nm for Ln 3+ series), which results in an ionic size mismatch between the dopants (Ln 3+ ) and the Al 3+ cations, the solubility of lanthanide cations in alumina is a significant challenge1314. Additionally, there is a limited understanding of the local structures and distributions of Ln-ions within the alumina matrix1516171819. Previous reports on Ln-doping of alumina have generally been conducted at doping concentrations of 0.5–5 wt%202122232425.…”