Lanthanide-Based Metal-Organic Frameworks with Upconversion/Downshifting Emission for Optical Information Encryption.

Area of Science:

• Materials Science
• Inorganic Chemistry
• Nanotechnology

Background:

• Lanthanide-based metal-organic frameworks (Ln-MOFs) are primarily recognized for downshifting luminescence.
• Achieving upconversion luminescence in Ln-MOFs remains a significant challenge in materials science.

Purpose of the Study:

• To design and synthesize a novel Yb-IPA MOF capable of upconversion luminescence.
• To explore the potential of codoping Yb-IPA MOFs with other lanthanide ions (Tb³⁺, Eu³⁺, Ho³⁺) for multimode luminescence.
• To investigate the application of these MOFs in information security, particularly for anticounterfeiting and encryption.

Main Methods:

• Synthesis of a Yb-IPA MOF using isophthalic acid and Yb³⁺ salt.
• Characterization of the synthesized MOF for its luminescent properties.
• Codoping the Yb-IPA MOF with Tb³⁺, Eu³⁺, and Ho³⁺ ions.
• Investigating the downshifting and upconversion luminescence under UV and near-infrared excitation, respectively.

Main Results:

• Successful synthesis of a Yb-IPA MOF exhibiting upconversion luminescence at 498 nm via cooperative upconversion under 980 nm excitation.
• Achievement of characteristic upconversion emissions from Tb³⁺, Eu³⁺, and Ho³⁺ in the codoped Yb-IPA MOFs.
• Demonstration of both downshifting and upconversion luminescence in the codoped MOFs, enabling multimode emission.

Conclusions:

• The developed Yb-IPA MOF system successfully achieves lanthanide upconversion luminescence.
• Codoping with Tb³⁺, Eu³⁺, and Ho³⁺ expands the luminescent capabilities, creating a multimode-emission system.
• This MOF system holds significant potential for advanced optical anticounterfeiting and information encryption technologies.