source:nature
All-inorganic lead-free perovskite-derivative metal halides are promising in optoelectronics. However, it remains challenging to realize efficient near-infrared (NIR) luminescence in these materials.
A research group led by Prof. CHEN Xueyuan from Fujian Institute of Research on the Structure of Matter of the Chinese Academy of Sciences (CAS) developed novel near-ultraviolet (NUV) light-emitting diode (LED)-excitable NIR emitters based on efficient energy transfer from Te4+ to Ln3+ (Ln = Er, Nd, and Yb) in vacancy-ordered double perovskite Cs2ZrCl6 phosphors.
The study was published in Angewandte Chemie International Edition.
Lanthanide (Ln3+) doping may endow the materials with NIR emission, but is limited by the small absorption coefficient of Ln3+ due to the parity-forbidden transitions within the 4fN configurations.
The researchers proposed a strategy via Te4+/Ln3+ (Ln=Er, Nd, and Yb) co-doping to achieve efficient NIR emission in perovskite-derivative Cs2ZrCl6 microcrystals (MCs).
Through sensitization by the spin-orbital allowed 1S0 → 3P1 transition of Te4+, the researchers achieved intense and multi-wavelength NIR luminescence originating from the 4f → 4f transitions of Er3+, Nd3+, and Yb3+.
Besides, the researchers demonstrated the excellent air-, structure-, and photo-stability of these Te4+/Ln3+ co-doped Cs2ZrCl6 and revealed their potentials as vis/NIR dual-emitters for applications in NUV-converted NIR-LEDs.
These findings provide an approach to achieve efficient NIR emission in lead-free metal halides through ns2-metal and lanthanide ion co-doping.
Schematic of efficient NIR luminescence in Te4+/Ln3+ co-doped Cs2ZrCl6 microcrystals (Image by Prof. CHEN’s group)
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