SciTech Connect

Title: Self-activating and doped tantalate phosphors.

Self-activating and doped tantalate phosphors. An ideal red phosphor for blue LEDs is one of the biggest challenges for the solid-state lighting industry. The appropriate phosphor material should have good adsorption and emission properties, good thermal and chemical stability, minimal thermal quenching, high quantum yield, and is preferably inexpensive and easy to fabricate. Tantalates possess many of these criteria, and lithium lanthanum tantalate materials warrant thorough investigation. In this study, we investigated red luminescence of two lithium lanthanum tantalates via three mechanisms: (1) Eu-doping, (2) Mn-doping and (3) self-activation of the tantalum polyhedra. Of these three mechanisms, Mn-doping proved to be the most promising. These materials exhibit two very broad adsorption peaks; one in the UV and one in the blue region of the spectrum; both can be exploited in LED applications. Furthermore, Mn-doping can be accomplished in two ways; ion-exchange and direct solid-state synthesis. One of the two lithium lanthanum tantalate phases investigated proved to be a superior host for Mn-luminescence, suggesting the crystal chemistry of the host lattice is important.
Authors: ;
Publication Date:
OSTI Identifier:OSTI ID: 1010419
Report Number(s):SAND2011-0173
TRN: US201108%%370
DOE Contract Number:AC04-94AL85000
Resource Type:Technical Report
Research Org:Sandia National Laboratories
Sponsoring Org:USDOE
Country of Publication:United States
Language:English
Subject: 36 MATERIALS SCIENCE; ADSORPTION; LIGHT EMITTING DIODES; LANTHANUM COMPOUNDS; LITHIUM COMPOUNDS; LUMINESCENCE; PHOSPHORS; TANTALATES; DOPED MATERIALS; EUROPIUM; MANGANESE