Rb₂HfCl₆:Sb³⁺phosphors with tunable energy transfer for advanced information encryption and high-CRI WLEDS.

Area of Science:

• Materials Science
• Solid-State Physics
• Optoelectronics

Background:

• Controllable multi-excitonic emission in single-phase systems is crucial for next-generation smart optoelectronics.
• Zero-dimensional (0D) vacancy-ordered double perovskites offer a promising platform due to exciton localization.
• Engineering dopant energy levels is key to tuning optical properties.

Purpose of the Study:

• To engineer a dynamic energy transfer landscape in Rb2HfCl6 via Sb3+ doping.
• To achieve controllable multi-excitonic emission and tunable colors.
• To explore applications in anti-counterfeiting and white LEDs.

Main Methods:

• Strategic introduction of Sb3+ dopants into a 0D vacancy-ordered double perovskite (Rb2HfCl6).
• Tailoring Sb3+ impurity levels to establish excitation-wavelength-driven equilibrium between host and dopant self-trapped excitons (STEs).
• Characterization of photoluminescence quantum yield (PLQY) and emission color switching.

Main Results:

• Achieved efficient self-trapped exciton (STE) emission with a PLQY of 59%.
• Enabled seamless switching of emission colors from green to orange-red by varying excitation wavelength (254-365 nm).
• Demonstrated potential for multi-level anti-counterfeiting smart locks and high-color-rendering white LEDs (CRI = 90.2).

Conclusions:

• Excitonic state engineering in low-dimensional metal halides is a powerful strategy for designing smart-responsive photonic materials.
• Sb3+ doping in Rb2HfCl6 provides a robust platform for tunable multi-excitonic emission.
• The developed material shows significant promise for advanced optoelectronic applications.