First-Principles Study on Structural, Electronic, and Spectroscopic Properties of γ-Ca2SiO4:Ce(3+) Phosphors

Area of Science:

• Materials Science
• Solid-State Chemistry
• Computational Physics

Background:

• Gamma-Ca2SiO4 phosphors doped with cerium (Ce3+) are promising for white light-emitting diodes (w-LEDs).
• Understanding the local environment and electronic structure of Ce3+ is crucial for optimizing phosphor performance.

Purpose of the Study:

• To investigate the geometric structures, electronic properties, and 4f → 5d transitions of Ce3+ in γ-Ca2SiO4.
• To explore the influence of various dopant/defect neighbors on the properties of γ-Ca2SiO4:Ce3+ phosphors.
• To provide insights for designing high-performance Ce3+-based phosphors for w-LED applications.

Main Methods:

• First-principles calculations based on Density Functional Theory (DFT) for geometry optimization.
• Heyd-Scuseria-Ernzerhof (HSE) screened hybrid functional for electronic property calculations.
• Ab initio embedded cluster calculations (CASSCF/CASPT2/RASSI-SO) for 4f → 5d transition analysis.

Main Results:

• Determined preferred crystallographic sites and local structures for Ce3+ in γ-Ca2SiO4 under different doping/defect conditions.
• Calculated electronic properties and simulated 4f → 5d transition energies and oscillator strengths for Ce3+.
• Achieved satisfactory agreement between theoretical calculations and available experimental results.

Conclusions:

• Established relationships between dopant/defect configurations and the electronic/spectroscopic properties of γ-Ca2SiO4:Ce3+.
• The study provides essential data for the rational design of advanced Ce3+-based phosphors for w-LEDs.