Electronic Spectra of Cs₂NaYb(NO₂)₆: Is There Quantum Cutting?

Area of Science:

• Solid State Chemistry
• Materials Science
• Spectroscopy

Background:

• The study investigates the crystal structure and electronic properties of hexanitritoytterbate(III) anions.
• Ytterbium(III) (Yb3+) emission can be sensitized by the nitrite (NO2-) ligand, acting as an antenna.

Purpose of the Study:

• To analyze the crystal structure and electronic spectra of Cs2NaY0.96Yb0.04(NO2)6.
• To investigate quantum cutting phenomena in Yb3+-doped materials.
• To determine the energy level scheme of Yb3+ and perform crystal field calculations.

Main Methods:

• Crystallography to determine the crystal structure (cubic space group Fm3̅).
• Spectroscopic analysis (excitation and emission spectra) to study electronic transitions and energy transfer.
• Crystal field theory and the f-Spectra package for energy level calculations.

Main Results:

• The compound Cs2NaY0.96Yb0.04(NO2)6 exhibits T h symmetry.
• Quantum cutting was observed at room temperature (298 K) and low temperature (25 K), with quantum efficiency around 10% at 25 K.
• Energy level schemes for Yb3+ were deduced and calculated, with improved calculations for related lanthanide compounds.

Conclusions:

• The Yb3+ emission can be effectively excited by the NO2- antenna, with energy transfer efficiency influenced by excitation wavelength and temperature.
• While quantum cutting is demonstrated, the neat Cs2NaYb(NO2)6 crystal shows sample decomposition, limiting its practical applications due to chemical instability.