As demand grows for high-performance luminescent materials in solid-state lighting, bioimaging, and anti-counterfeiting, the challenge of enhancing emission efficiency in metal–organic frameworks (MOFs) remains critical. Now, researchers from Jilin University, led by Professor Xinyi Yang, have developed a breakthrough strategy using pressure treatment to significantly enhance the blue-light emission of MIL-140A nanocrystals. This work offers a clean, efficient, and scalable approach to modulate luminescence in MOF-based materials.
Why Pressure-Modulated Luminescence Matters
- Efficiency Boost: The photoluminescence quantum yield (PLQY) of MIL-140A increased dramatically from 6.8% to 69.2% after pressure treatment — a 10-fold enhancement.
- Mechanism Insight: Pressure induces pore contraction, strengthening host–guest interactions and suppressing non-radiative energy loss from ligand rotation.
- Ambient Stability: The enhanced emission is retained under normal conditions for over 3 months, enabling practical applications.
- Universal Strategy: This approach is transferable to other MOF systems with rotatable ligands, offering a general path to high-performance luminescent materials.
Innovative Design and Features
- Rotor Ligand System: MIL-140A uses 1,4-benzenedicarboxylic acid (BDC) as a rotatable ligand, which typically causes energy dissipation via molecular motion.
- Guest Molecule Tuning: DMF molecules within the MOF pores interact with BDC ligands under pressure, forming hydrogen bonds that restrict rotation and vibration.
- Structural Rigidity: Pressure-induced pore shrinkage enhances framework stiffness, reducing non-radiative decay and enabling efficient radiative recombination.
- In Situ Characterization: Techniques including high-pressure PL, IR, Raman, and X-ray diffraction reveal the structural and electronic origins of emission enhancement.
Applications and Future Outlook
- Solid-State Lighting: Bright, stable blue emission makes MIL-140A a candidate for LED and display technologies.
- Optical Sensing: Pressure-responsive emission opens new avenues for mechanical sensors and smart devices.
- Anti-Counterfeiting: The reversible and tunable emission properties are ideal for security inks and optical tags.
- Scalability: The pressure treatment process is clean, solvent-free, and compatible with large-scale material processing.
Challenges and Opportunities
The study highlights the importance of pore size and guest–ligand compatibility in achieving emission enhancement. Future research will explore the generalizability of this strategy across other MOF families and integrate these materials into functional optoelectronic devices.
This work demonstrates a powerful and reversible strategy to unlock high-efficiency luminescence in MOFs through pressure engineering, providing new insights into structure–property relationships and paving the way for next-generation luminescent materials. Stay tuned for more innovative research from Professor Xinyi Yang’s team at Jilin University!