Environmentally-Friendly Europium-Based Yellow Perovskite Nanocrystals with Near-Unit Efficiency for White LED

Area of Science:

• Materials Science
• Solid-State Chemistry
• Photonic Materials

Background:

• Manganese (Mn²⁺)-doped metal halide perovskites (MHPs) offer improved photoluminescence quantum yield (PLQY) with reduced self-absorption.
• Existing high-efficiency MHPs predominantly use toxic lead (Pb) or cadmium (Cd), hindering commercial viability.
• There is a critical need for efficient and environmentally benign luminescent materials for advanced applications.

Purpose of the Study:

• To develop efficient and eco-friendly luminescent materials by incorporating Mn²⁺ into CsEuX₃ perovskites.
• To enhance the photoluminescence quantum yield (PLQY) through codoping with terbium (Tb³⁺).
• To investigate the potential of these materials for white light-emitting diode (WLED) applications.

Main Methods:

• Synthesis of Mn²⁺-doped and Mn²⁺/Tb³⁺-codoped CsEuX₃ (X = Cl/Br) perovskite materials.
• Photoluminescence spectroscopy to measure PLQY and analyze emission properties.
• Fabrication and characterization of white light-emitting diodes (WLEDs) incorporating the developed phosphors.

Main Results:

• Achieved a record-high PLQY of 96.9% for Mn²⁺/Tb³⁺-codoped CsEuX₃, the highest reported for inorganic, environmentally friendly perovskites in the visible spectrum.
• Demonstrated that Tb³⁺ codoping reduces host defect density and enhances the crystal field around Mn²⁺, facilitating energy transfer.
• Developed WLEDs using Mn²⁺/Tb³⁺-codoped CsEuX₃ with a high color rendering index (Ra = 91.2).

Conclusions:

• Mn²⁺/Tb³⁺ codoping in CsEuX₃ is a promising strategy for creating highly efficient, environmentally friendly luminescent materials.
• These materials exhibit excellent potential for next-generation lighting applications, particularly in WLEDs.
• The study overcomes the limitations of toxic heavy-metal-based perovskites, paving the way for sustainable lighting solutions.