Researchers develop novel near-ultraviolet LED-excitable near-infrared emitters

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 4f^N 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.