Highly Conductive Chiral Organic Cages and Their Helical Assemblies Enable Efficient Spin Filtering

Area of Science:

• Materials Science
• Organic Chemistry
• Spintronics

Background:

• Chiral molecular cages offer unique properties for enantioselective chemistry.
• The influence of cage chirality on electronic spin behavior in condensed materials is largely unexplored.
• Chirality-induced spin selectivity (CISS) offers a pathway for spin manipulation.

Purpose of the Study:

• To investigate the potential of chiral organic molecular cages for spin filtering applications.
• To explore the relationship between cage chirality and spin-selective transport properties.
• To develop novel chiral materials for spintronic devices.

Main Methods:

• Synthesis of chiral organic molecular cages (Pcages) containing triphenylphosphine.
• Fabrication of thin-film spin filter devices using Pcages.
• Self-assembly of Pcages with triphenylborane to form supramolecular nanofibrils.
• Measurement of spin polarization, conductivity, and magnetoresistance.

Main Results:

• Chiral Pcages exhibited high spin polarization (nearly 90%) and conductivity exceeding other chiral materials by two orders of magnitude.
• Thin-film devices demonstrated significant magnetoresistance ratios (up to 12%) based on the CISS effect.
• Self-assembled homochiral helical nanofibrils from Pcages and triphenylborane showed enhanced spin transport and magnetoresistance.

Conclusions:

• Chiral organic molecular cages represent a promising platform for realizing efficient spin filtering.
• The CISS effect in these cages can be harnessed for spintronic applications.
• Self-assembly offers a route to enhance the spin-selective properties of cage-based materials.