Atomically dispersed Pb ionic sites in PbCdSe quantum dot gels enhance room-temperature NO₂ sensing

Area of Science:

• Materials Science
• Environmental Science
• Chemistry

Background:

• Atmospheric nitrogen dioxide (NO2) poses significant risks to human health and the environment.
• Current low-cost NO2 sensors struggle with low sensitivity at parts-per-billion (ppb) levels and slow recovery times.
• A need exists for advanced materials enabling efficient NO2 detection and remediation.

Purpose of the Study:

• To develop a high-performance room-temperature NO2 sensor with improved sensitivity and recovery.
• To investigate the potential of atomically dispersed metal ions in quantum dot (QD) materials for gas sensing.
• To understand the mechanism behind enhanced NO2 detection using bimetallic QD gels.

Main Methods:

• Synthesis of bimetallic PbCdSe quantum dot (QD) gels with atomically dispersed Pb ionic sites.
• Fabrication and characterization of a p-type semiconductor NO2 sensor using the QD gel.
• Performance evaluation including limit of detection, sensitivity, stability, response, and recovery times.
• Theoretical calculations to elucidate the role of Pb ionic sites in NO2 binding.

Main Results:

• The PbCdSe QD gel demonstrated an optimal balance of strong sensor response and fast recovery.
• The sensor exhibited an ultra-low limit of detection, high sensitivity, and excellent stability at room temperature.
• Fast response and recovery times were achieved, addressing a key limitation of existing sensors.
• Theoretical analysis confirmed that Pb ionic sites enhance NO2 binding to neighboring Cd sites.

Conclusions:

• Atomically dispersed Pb ionic sites in PbCdSe QD gels are effective for high-performance NO2 sensing.
• This strategy overcomes the typical trade-off between sensor response and recovery time.
• The developed sensor offers a promising solution for sensitive and rapid room-temperature NO2 detection.