Efficient Near-Infrared Luminescence Based on Double Perovskite Cs₂SnCl₆

Area of Science:

• Materials Science
• Solid-State Chemistry
• Optoelectronics

Background:

• Cesium Tin Chloride (Cs2SnCl6) double perovskites are promising lead-free optoelectronic materials due to their enhanced stability and reduced toxicity.
• Pure Cs2SnCl6 exhibits poor optical properties, necessitating doping for efficient luminescence.
• Active element doping is crucial for tuning the optoelectronic properties of Cs2SnCl6.

Purpose of the Study:

• To synthesize Te4+ and Er3+ co-doped Cs2SnCl6 microcrystals using a facile co-precipitation method.
• To investigate the luminescence properties of the co-doped Cs2SnCl6, particularly near-infrared (NIR) emissions.
• To explore the underlying mechanisms of luminescence sensitization and energy transfer in the co-doped system.

Main Methods:

• Co-precipitation synthesis of polyhedral Cs2SnCl6 microcrystals (1-3 μm).
• Characterization of structural and optical properties of Te4+ and Er3+ co-doped Cs2SnCl6.
• Analysis of luminescence spectra, lifetimes, and energy transfer mechanisms.

Main Results:

• Achieved highly efficient NIR emissions at 1540 nm and 1562 nm due to Er3+ in Cs2SnCl6 for the first time.
• Observed decreased visible luminescence lifetimes with increasing Er3+ concentration, indicating efficient energy transfer.
• Demonstrated sensitization of Er3+ 4f→4f transitions by Te4+ 1S0→3P1 transition via a self-trapped exciton (STE) state.

Conclusions:

• Te4+ and Er3+ co-doping effectively enhances the luminescence properties of Cs2SnCl6.
• The co-doping strategy successfully extends the emission range of Cs2SnCl6 to the NIR region.
• Co-doping with ns2-metal and lanthanide ions is a viable approach for developing advanced optoelectronic materials.