Isomorphism of Sr[LiAlO] and Sr[LiGaO] - Syntheses, Crystal Structure, and Europium(II) Luminescence.

While highly efficient red-emitting inorganic phosphors have been discovered in the substance class of alkaline earth oxo(nitrido)lithoaluminates, new narrow-band green- and yellow-emitting components are being sought to improve the performance of phosphor-converted light-emitting diodes (pc-LEDs). Various solid-state reactions were carried out under protective gas atmosphere in nickel crucibles and sealed tantalum ampules to synthesize Sr[LiAlO], Sr[LiGaO], and five substitutional derivates of Sr[Li(Al Ga )O] at moderate temperatures. The observation of a linear increase in the unit cell parameters as a function of the increasing gallium mole fraction in Sr[Li(Al Ga )O] revealed Vegard behavior in the solid-solution series, which was derived from powder X-ray diffraction data.

Improving LED Efficiency with the New Polymorph β-Ca Sr AlSiN :Eu.

Innovative materials for phosphor-converted white light-emitting diodes (pc-LEDs) are much sought after due to the huge potential of the LED technology to reduce energy consumption worldwide. One of the main levers for further improvements are the conversion phosphors. The system Ca Sr AlSiN :Eu currently provides one of the most important red-emitting phosphors for pc-LEDs.

Complex interrupted tetrahedral frameworks in the nitridosilicates M7Si6N15 (M = La, Ce, Pr).

A new structure type of nitridosilicates with an interrupted framework has been identified for M(7)Si(6)N(15) with M = La, Ce, and Pr. The materials have been synthesized in a radio-frequency furnace at temperatures between 1550-1625 degrees C, starting from the respective metals, metal nitrides, and silicon diimide. The crystal structure of Ce(7)Si(6)N(15) has been determined by using single-crystal X-ray diffraction.

Mixed valence europium nitridosilicate Eu2SiN3.

The mixed valence europium nitridosilicate Eu(2)SiN(3) has been synthesized at 900 degrees C in welded tantalum ampules starting from europium and silicon diimide Si(NH)(2) in a lithium flux. The structure of the black material has been determined by single-crystal X-ray diffraction analysis (Cmca (no. 64), a = 542.