title: Ammonothermal Synthesis of Novel Nitrides: Case Study on CaGaSiN3.
abstract: The first gallium-containing nitridosilicate CaGaSiN3was synthesized in newly developed high-pressure autoclaves using supercritical ammonia as solvent and nitriding agent. The reaction was conducted in an ammonobasic environment starting from intermetallic CaGaSi with NaN3as a mineralizer. At 770 K, intermediate compounds were obtained, which were subsequently converted to the crystalline nitride at temperatures up to 1070 K (70-150 MPa). The impact of other mineralizers (e.g., LiN3, KN3, and CsN3) on the product formation was investigated as well. The crystal structure of CaGaSiN3was analyzed by powder X-ray diffraction and refined by the Rietveld method. The structural results were further corroborated by transmission electron microscopy,29Si MAS-NMR, and first-principle DFT calculations. CaGaSiN3crystallizes in the orthorhombic space group Cmc21(no. 36) with lattice parameters a=9.8855(11), b=5.6595(1), c=5.0810(1) Å, (Z=4, Rwp=0.0326), and is isostructural with CaAlSiN3(CASN). Eu2+doped samples exhibit red luminescence with an emission maximum of 620 nm and FWHM of 90 nm. Thus, CaGaSiN3:Eu2+also represents an interesting candidate as a red-emitting material in phosphor-converted light-emitting diodes (pc-LEDs). In addition to the already known substitution of alkaline-earth metals in (Ca,Sr)AlSiN3:Eu2+, inclusion of Ga is a further and promising perspective for luminescence tuning of widely used red-emitting CASN type materials.
authors.affiliation: Department of Chemistry, University of Munich (LMU), Butenandtstr. 5-13, 81377, Munich, Germany.
authors.forename: Jonas
authors.initials: J
authors.lastname: Häusler
authors.affiliation: Department of Chemistry, University of Munich (LMU), Butenandtstr. 5-13, 81377, Munich, Germany.
authors.forename: Lukas
authors.initials: L
authors.lastname: Neudert
authors.affiliation: Department of Chemistry, University of Munich (LMU), Butenandtstr. 5-13, 81377, Munich, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Mallmann
authors.affiliation: Department of Chemistry, University of Munich (LMU), Butenandtstr. 5-13, 81377, Munich, Germany.
authors.forename: Robin
authors.initials: R
authors.lastname: Niklaus
authors.affiliation: Institute of Process Machinery and Systems Engineering, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Cauerstr. 4, 91058, Erlangen, Germany.
authors.forename: Anna-Carina L
authors.initials: AL
authors.lastname: Kimmel
authors.affiliation: Institute of Process Machinery and Systems Engineering, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Cauerstr. 4, 91058, Erlangen, Germany.
authors.forename: Nicolas S A
authors.initials: NS
authors.lastname: Alt
authors.affiliation: Institute of Process Machinery and Systems Engineering, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Cauerstr. 4, 91058, Erlangen, Germany.
authors.forename: Eberhard
authors.initials: E
authors.lastname: Schlücker
authors.affiliation: Faculty of Chemistry and Mineralogy, Institute for Mineralogy, Crystallography and Materials Science, Leipzig University, Scharnhorststr. 20, 04275, Leipzig, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Oeckler
authors.affiliation: Department of Chemistry, University of Munich (LMU), Butenandtstr. 5-13, 81377, Munich, Germany.
authors.forename: Wolfgang
authors.identifier: http://orcid.org/0000-0003-4571-8035
authors.initials: W
authors.lastname: Schnick
keywords: ammonothermal synthesis; electron diffraction; luminescence; nitrides; nitridosilicates