Prospecting Lighting Applications with Ligand Field Tools and Density Functional Theory: A First-Principles Account of the 4f(7)-4f(6)5d(1) Luminescence of CsMgBr3:Eu(2+).
The most efficient way to provide domestic lighting nowadays is by light-emitting diodes (LEDs) technology combined with phosphors shifting the blue and UV emission toward a desirable sunlight spectrum. A route in the quest for warm-white light goes toward the discovery and tuning of the lanthanide-based phosphors, a difficult task, in experimental and technical respects. A proper theoretical approach, which is also complicated at the conceptual level and in computing efforts, is however a profitable complement, offering valuable structure-property rationale as a guideline in the search of the best materials. The Eu(2+)-based systems are the prototypes for ideal phosphors, exhibiting a wide range of visible light emission. Using the ligand field concepts in conjunction with density functional theory (DFT), conducted in nonroutine manner, we develop a nonempirical procedure to investigate the 4f(7)-4f(6)5d(1) luminescence of Eu(2+) in the environment of arbitrary ligands, applied here on the CsMgBr3:Eu(2+)-doped material. Providing a salient methodology for the extraction of the relevant ligand field and related parameters from DFT calculations and encompassing the bottleneck of handling large matrices in a model Hamiltonian based on the whole set of 33,462 states, we obtained an excellent match with the experimental spectrum, from first-principles, without any fit or adjustment. This proves that the ligand field density functional theory methodology can be used in the assessment of new materials and rational property design.
Department of Chemistry, University of Fribourg , Chemin du Musée 9, 1700 Fribourg, Switzerland.
Harry
H
Ramanantoanina
Institute of Physical Chemistry , Splaiul Independentei 202, Bucharest 060021, Romania.
Fanica
F
Cimpoesu
Department of Chemistry, University of Fribourg , Chemin du Musée 9, 1700 Fribourg, Switzerland.
Christian
C
Göttel
Laboratoire de physique de la matière et modélisation mathématique LPQ3M, Université de Mascara , Mascara, Algerie.
Mohammed
M
Sahnoun
Department of Chemistry, University of Fribourg , Chemin du Musée 9, 1700 Fribourg, Switzerland.
Benjamin
B
Herden
Faculty of Science and Technology, University of Siegen , Adolf-Reichwein Strasse 2, 57068 Siegen, Germany.
Markus
M
Suta
Faculty of Science and Technology, University of Siegen , Adolf-Reichwein Strasse 2, 57068 Siegen, Germany.
Claudia
C
Wickleder
Department of Chemistry, University of Fribourg , Chemin du Musée 9, 1700 Fribourg, Switzerland.
Werner
W
Urland
Department of Chemistry, University of Fribourg , Chemin du Musée 9, 1700 Fribourg, Switzerland.
Claude
C
Daul