Highly Efficient MAPbI₃-Based Quantum Dots Exhibiting Unusual Nonblinking Single Photon Emission at Room Temperature

Area of Science:

• Materials Science
• Nanotechnology
• Quantum Optics

Background:

• Semiconductor nanocrystals, or quantum dots (QDs), are highly emissive and used in displays, labeling, and quantum communication.
• Existing QDs show high photoluminescent quantum yields (PLQYs) in ensembles but lack non-blinking, high-intensity emission at the single-dot level at room temperature.
• Achieving non-blinking single-photon emission with high purity remains a critical challenge for quantum emitters.

Purpose of the Study:

• To demonstrate infrared-emissive MAPbI₃-based halide perovskite quantum dots (QDs).
• To investigate their photoluminescent quantum yields (PLQYs) and single-dot emission properties.
• To explore the underlying mechanisms for non-blinking behavior and high single-photon purity.

Main Methods:

• Synthesis of MAPbI₃-based halide perovskite QDs.
• Measurement of ensemble and single-dot photoluminescence quantum yields (PLQYs).
• Characterization of absorption cross-section, single-photon purity, and blinking behavior.
• Fluence-dependent transient absorption measurements.
• Stability testing under electron irradiation using high-resolution transmission electron microscopy.

Main Results:

• Perovskite QDs exhibit ≈100% PLQY at the ensemble level and high emission intensity at the single-dot level.
• Demonstrated non-blinking single-photon emission with 95.3% purity and a large absorption cross-section (1.80 × 10^-12 cm²) at room temperature.
• Absence of trion formation and band-edge carrier trapping, attributed to repulsive exciton-exciton interactions suppressing biexciton formation and photocharging.
• QDs show excellent stability under continuous electron irradiation.

Conclusions:

• MAPbI₃ perovskite QDs overcome the limitations of conventional QDs by providing non-blinking, high-purity single-photon emission at room temperature.
• The observed properties are due to suppressed photocharging via strong exciton-exciton repulsion.
• These findings represent a significant milestone toward realizing practical non-blinking single-photon emitters for advanced applications.