Multimodal Luminescence in an Excellent Stable Single-Host Nanocrystal by Leveraging Self-Trapped States and Shallow...

Area of Science:

• Materials Science
• Nanotechnology
• Solid-State Chemistry

Background:

• Developing single-host nanomaterials with multiple stable luminescent modes is critical for anticounterfeiting and information encryption.
• Existing challenges include achieving high stability and integrating diverse luminescent functionalities.

Purpose of the Study:

• To synthesize and characterize manganese-doped Cs2NaYbCl6 double perovskite nanocrystals (NCs) with multimodal luminescence.
• To investigate the underlying mechanisms for the observed luminescence properties and their stability.
• To demonstrate the potential of these NCs in anticounterfeiting and information encryption applications.

Main Methods:

• Modified hot-injection method for synthesizing Mn2+-doped Cs2NaYbCl6 double perovskite NCs.
• Characterization of optical properties including downshifting luminescence, persistent luminescence (PersL), and temperature-dependent multicolor luminescence.
• Assessment of environmental stability and demonstration of anticounterfeiting/encryption functionalities.

Main Results:

• Successfully synthesized Mn2+-doped Cs2NaYbCl6 NCs exhibiting extraordinary multimodal luminescence.
• Observed dual-color downshifting (UV, X-ray), persistent luminescence, and temperature-dependent multicolor emission.
• Demonstrated exceptional environmental stability, retaining properties after six months in air.
• Attributed multimodal luminescence to the interplay of self-trapped exciton states, Mn2+ energy levels, and host defects.
• Identified shallow defects and chlorine vacancies as origins of persistent luminescence.

Conclusions:

• Mn2+-doped Cs2NaYbCl6 NCs are a highly promising material for advanced anticounterfeiting and information encryption due to their multimodal luminescence and stability.
• The harmonious integration of various luminescent pathways within a single host is achieved.
• The material demonstrates significant potential for commercial security applications.