Enhancing the NIR Emission in Cs₂ScCl₅·H₂O:Cr³⁺ Phosphor via Te⁴⁺ Sensitization

Area of Science:

• Materials Science
• Inorganic Chemistry
• Solid-State Physics

Background:

• Lead-free metal halide perovskites are explored for near-infrared (NIR) emission applications.
• Achieving efficient NIR emission in these materials remains a significant challenge.
• Cr³⁺ doping in suitable matrices is a common strategy for NIR luminescence.

Purpose of the Study:

• To enhance the near-infrared (NIR) luminescence of Cr³⁺-doped Cs₂ScCl₅·H₂O.
• To investigate the effect of codoping with Te⁴⁺ ions on NIR emission properties.
• To explore potential applications of the developed material.

Main Methods:

• Synthesizing Cs₂ScCl₅·H₂O doped with Cr³⁺ and codoped with Te⁴⁺.
• Characterizing the photoluminescence properties, including NIR emission and photoluminescence quantum yield (PLQY).
• Evaluating the energy transfer mechanisms involving self-trapped excitons (STEs).

Main Results:

• Codoping with Te⁴⁺ ions significantly enhanced the NIR emission from the ⁴T₂ → ⁴A₂ transition of Cr³⁺.
• The photoluminescence quantum yield (PLQY) reached 11.02%.
• A 3-fold increase in NIR emission intensity was observed compared to singly Cr³⁺-doped samples, along with new yellow emission.

Conclusions:

• Codoping with Te⁴⁺ is an effective strategy to boost NIR emission in lead-free Cs₂ScCl₅·H₂O:Cr³⁺.
• The weak symmetry of the Cs₂ScCl₅·H₂O matrix is beneficial for broadband NIR emission.
• The material shows potential for applications in nondestructive testing and night vision.