New red-emitting phosphor Rb K_3- SiF₇:Mn⁴⁺ (x = 0, 1, 2, 3): DFT predictions and synthesis

Area of Science:

• Materials Science
• Solid-State Chemistry
• Computational Materials Science

Background:

• Developing new phosphors is crucial for advanced lighting and display technologies.
• Efficient methods for discovering novel phosphors are needed to reduce development time and cost.
• Computational simulations offer a promising avenue for predicting material properties before synthesis.

Purpose of the Study:

• To demonstrate the utility of density functional theory (DFT) calculations in guiding the development of a new red phosphor.
• To predict the stability, electronic structure, and luminescence properties of Mn-doped Rb_xK_3-xSiF₇.
• To synthesize and characterize a novel red conversion phosphor identified through DFT calculations.

Main Methods:

• First-principles calculations based on DFT were performed for pristine and Mn-doped Rb_xK_3-xSiF₇ (x = 0, 1, 2, 3).
• Calculations predicted material stability, electronic band structure, and optical properties.
• The most promising candidate material was synthesized and its luminescence, structure, and stability were experimentally investigated.

Main Results:

• DFT calculations successfully predicted the properties of Mn-doped Rb_xK_3-xSiF₇ compounds.
• The synthesized Rb₂KSiF₇:Mn⁴⁺ phosphor exhibited red light emission.
• The emission wavelength of Rb₂KSiF₇:Mn⁴⁺ was longer than K₃SiF₇:Mn⁴⁺ and similar to K₂SiF₆:Mn⁴⁺.

Conclusions:

• Density functional theory calculations provide reliable insights for designing phosphor materials.
• Computational methods can significantly accelerate the discovery and development of new red conversion phosphors.
• This approach minimizes the time and financial investment required for novel phosphor synthesis and characterization.