W-Doped Cs₂SnCl₆ for Near-Infrared Emission

Area of Science:

• Materials Science
• Solid-State Chemistry
• Photophysics

Background:

• Zero-dimensional (0D) perovskite derivatives, such as Cs2WCl6 and Cs2WOCl6-, exhibit near-infrared (NIR) emission due to d-d electronic transitions of tungsten (W).
• Concentration quenching, caused by the close proximity of emitting ions, limits the photoluminescence efficiency in these materials.

Purpose of the Study:

• To overcome concentration quenching in NIR-emitting 0D perovskites.
• To investigate the potential of doping tungsten into Cs2SnCl6 as a strategy for efficient NIR phosphors.

Main Methods:

• Dilution of emission centers by doping a small amount of W into the Cs2SnCl6 0D perovskite lattice.
• Characterization of the W-doped Cs2SnCl6 material and its photoluminescence properties.
• Fabrication and testing of NIR phosphor-converted light-emitting diodes (LEDs) using the W-doped material.

Main Results:

• The dopant centers were identified as [WOCl5]2- ions substituting for [SnCl6]2- octahedra in the Cs2SnCl6 host lattice.
• Optimal 3.3% W-doped Cs2SnCl6 showed over 52 times higher NIR emission intensity at 965 nm compared to Cs2WOCl6-.
• Suppression of concentration quenching led to significantly altered temperature-dependent photoluminescence (7–300 K).
• Demonstrated NIR phosphor-converted LEDs with an output power of 10.3 mW at 400 mA.

Conclusions:

• W-doping in 0D Cs2SnCl6 is an effective strategy to suppress concentration quenching and enhance NIR emission.
• This study reports the first instance of W doping in 0D perovskites, highlighting their potential as efficient NIR phosphors.
• The developed W-doped Cs2SnCl6 material shows promise for applications in NIR optoelectronics.