Comprehensive Band Gap and Electronic Structure Investigations of the Prominent Phosphors M2Si5N8:Eu2+ (M = Ca, Sr, Ba) Determined Using Soft X-ray Spectroscopy and Density Functional Theory

Tolhurst, Thomas M.; Braun, Cordula; Schnick, Wolfgang und Moewes, Alexander (2021): Comprehensive Band Gap and Electronic Structure Investigations of the Prominent Phosphors M2Si5N8:Eu2+ (M = Ca, Sr, Ba) Determined Using Soft X-ray Spectroscopy and Density Functional Theory. In: Journal of Physical Chemistry C, Bd. 125, Nr. 46: S. 25799-25806

Abstract

The suite of LED phosphors M2Si5N8:Eu2+ (M = Ca, Sr, Ba) emerged as indispensable solid-state light sources for the next-generation lighting industry and display systems due to their unique properties. As such, the structure-property relations underpinning their electronic structures are of prime interest. Their band gaps, electronic structures, optical properties, and energy levels are studied with a combination of soft X-ray spectroscopy and density functional theory (DFT) calculations. A clear trend is found where the tunable band gaps range from 3.70 +/- 0.20 to 5.00 +/- 0.20 eV (when going from Ba to Sr to Ca), following the predictions of the bonding model. The measurements and calculations are also used to derive a systematic trend between the measured band gaps of M2Si5N8 and are confirmed by our density functional theory calculations employing different exchange correlation functionals. These investigations present a comprehensive picture of the M2Si5N8 system, underlining their broad applicability and importance as one of the preeminent phosphors for LED lighting.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Chemie und Pharmazie > Department Chemie
• Themengebiete: 500 Naturwissenschaften und Mathematik > 540 Chemie
• ISSN: 1932-7447
• Sprache: Englisch