Tuning the effective spin-orbit coupling in molecular semiconductors

Area of Science:

• Organic electronics
• Spintronics
• Molecular semiconductors

Background:

• Controlling spins and spin-to-charge conversion in organic materials necessitates understanding molecular spin-orbit coupling (SOC).
• Quantifying SOC strength indirectly via spin relaxation is challenging due to competing mechanisms.

Purpose of the Study:

• To systematically study g-tensor shifts in molecular semiconductors.
• To directly link g-tensor shifts to SOC strength in high-mobility organic materials.
• To explore the potential for future organic spintronic devices.

Main Methods:

• Investigated g-tensor shifts in a series of high-mobility molecular semiconductors.
• Correlated g-tensor shifts with spin-lattice relaxation times.
• Analyzed isolated molecules in solution and related findings to solid-state systems.

Main Results:

• Demonstrated significant variability in molecular g-shifts, directly correlating with effective SOC.
• Observed a wide range of spin-lattice relaxation times (200 to 0.15 μs).
• Established a link between molecular composition/structure and SOC strength.

Conclusions:

• G-tensor shifts serve as a reliable indicator of SOC strength in molecular semiconductors.
• Findings provide insights into spin relaxation mechanisms relevant for organic spintronic devices.
• This work facilitates the design of materials with tunable SOC for advanced applications.