Chemically Tuning Room Temperature Pulsed Optically Detected Magnetic Resonance

Area of Science:

• Quantum Sensing
• Molecular Systems
• Optically Detected Magnetic Resonance (ODMR)

Background:

• Spin-based quantum sensing leverages optical detection of magnetic resonance for high spatial resolution and sensitivity, even at room temperature.
• Solid-state defects like nitrogen-vacancy centers in diamond are established platforms, offering ~30% optical contrast.
• Molecular systems present a chemically tunable alternative for room-temperature ODMR quantum sensing.

Purpose of the Study:

• To demonstrate enhanced optical contrast in molecular systems for room-temperature ODMR-based quantum sensing.
• To investigate the mechanisms behind improved contrast in specifically designed molecular systems.
• To translate high-contrast ODMR techniques to self-assembled molecular nanocrystals.

Main Methods:

• Utilized a nitrogen-substituted analogue of pentacene (6,13-diazapentacene) to explore molecular ODMR.
• Employed time-dependent pulsed ODMR to determine triplet kinetics and understand contrast enhancement.
• Applied high-contrast room-temperature pulsed ODMR to self-assembled nanocrystals.

Main Results:

• Achieved room-temperature ODMR contrasts of 40% in molecular systems, exceeding state-of-the-art solid-state defects.
• Demonstrated that 6,13-diazapentacene exhibits enhanced contrast compared to pentacene.
• Identified accelerated anisotropic intersystem crossing as the mechanism for contrast improvement.

Conclusions:

• Molecular systems offer significant potential for room-temperature quantum sensing through chemical tunability.
• Synthetic modifications can optimize optically readable molecular spins for enhanced sensing performance.
• High-contrast ODMR in molecular nanocrystals opens avenues for advanced quantum sensing applications.