Sr_1/2Ce_5/14□_1/7WO₄: a new modulated ternary scheelite compound

Area of Science:

• Solid State Chemistry
• Materials Science
• Inorganic Chemistry

Background:

• Ternary tungstates with scheelite structures are important functional materials.
• Tuning the properties of scheelite tungstates through cation substitution is an active area of research.

Purpose of the Study:

• To synthesize and characterize a novel ternary tetragonal scheelite structure tungstate containing strontium and cerium cations.
• To investigate the structural, electronic, and optical properties of the synthesized (Sr,Ce)WO₄ compound.

Main Methods:

• Solid-state synthesis of (Sr,Ce)WO₄.
• High-resolution electron microscopy for structural analysis.
• Optical spectroscopy to determine the band gap.

Main Results:

• Successful synthesis of a ternary tetragonal scheelite structure (Sr,Ce)WO₄.
• Up to 35% cerium incorporation was achieved, with 1/7 cation sites vacant.
• Observed partial ordering of Sr and Ce, atomic displacements, and 2D incommensurate modulations.
• The band gap was significantly reduced compared to SrWO₄, attributed to polyhedral distortions.
• The band gap of 3.2 eV suggests potential for violet luminescence.

Conclusions:

• The new (Sr,Ce)WO₄ compound exhibits unique structural features and reduced band gap.
• The observed properties make Sr_1/2Ce_5/14□_1/7WO₄ a promising material for violet luminescence applications.