Anomalously bright single-molecule upconversion electroluminescence

Area of Science:

• Optoelectronics
• Molecular Electronics
• Photonics

Background:

• Efficient upconversion electroluminescence (UCEL) is crucial for optoelectronics.
• Previous UCEL research was limited to ensemble systems.
• Single-molecule emitters exhibited very low UCEL efficiency.

Purpose of the Study:

• To achieve bright single-molecule upconversion electroluminescence.
• To investigate mechanisms for enhancing UCEL efficiency in single molecules.
• To provide insights into single-molecule electroluminescence.

Main Methods:

• Engineering molecule-substrate interface energy-level alignments.
• Activating spin-triplet mediated UCEL mechanisms.
• Constructing electroluminescence diagrams for single-molecule excitation.

Main Results:

• Observed anomalously bright single-molecule UCEL.
• Improved emission efficiencies by over one order of magnitude.
• Achieved UCEL stronger than normal-bias electroluminescence.

Conclusions:

• Demonstrated a viable pathway for efficient single-molecule UCEL.
• Highlighted the importance of interface engineering for UCEL.
• Provided a framework for understanding and optimizing molecular electroluminescence.