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

Xin Geng,Alina Shafikova,Chathuranga C Hewa-Rahinduwage,Bingwen Wang,Tao Ma,Mohamed Kilani,Lu Ma,Shuwei Li,Eranda Nikolla,Liang Zhang,Long Luo,Guangzhao Mao,Lalani Mawella-Vithanage,Stephanie L Brock

doi:10.1038/s41467-021-25192-4

Abstract

Atmospheric NO2 is of great concern due to its adverse effects on human health and the environment, motivating research on NO2 detection and remediation. Existing low-cost room-temperature NO2 sensors often suffer from low sensitivity at the ppb level or long recovery times, reflecting the trade-off between sensor response and recovery time. Here, we report an atomically dispersed metal ion strategy to address it. We discover that bimetallic PbCdSe quantum dot (QD) gels containing atomically dispersed Pb ionic sites achieve the optimal combination of strong sensor response and fast recovery, leading to a high-performance room-temperature p-type semiconductor NO2 sensor as characterized by a combination of ultra–low limit of detection, high sensitivity and stability, fast response and recovery. With the help of theoretical calculations, we reveal the high performance of the PbCdSe QD gel arises from the unique tuning effects of Pb ionic sites on NO2 binding at their neighboring Cd sites.

Highlights

Atmospheric NO2 is of great concern due to its adverse effects on human health and the environment, motivating research on NO2 detection and remediation
Density functional theory (DFT) calculations suggest that the high performance of the PbxCd1−xSe quantum dot (QD) gel is caused by the unique tuning effects of atomically dispersed Pb ionic sites on NO2 binding at their neighboring Cd sites
PbxCd1−xSe QD gels were synthesized via a cation exchange process wherein x is controlled by the concentration of Pb(NO3)[2] in the exchange solution[48,51]: a greater Pb (NO3)[2] concentration leads to more Pb incorporation in the PbxCd1−xSe QD gels

Summary

Introduction

Atmospheric NO2 is of great concern due to its adverse effects on human health and the environment, motivating research on NO2 detection and remediation. We discover that bimetallic PbCdSe quantum dot (QD) gels containing atomically dispersed Pb ionic sites achieve the optimal combination of strong sensor response and fast recovery, leading to a high-performance room-temperature p-type semiconductor NO2 sensor as characterized by a combination of ultra–low limit of detection, high sensitivity and stability, fast response and recovery. We reported the high NO2 sensing performance of a CdS QD gel at room temperature, which demonstrated high selectivity, an ultra-low (measured, not extrapolated) limit of detection (LOD = 11 ppb), a short response time (tres = ~29 s) and recovery time (trec = ~28 s)[26]. We show the bimetallic PbxCd1−xSe QD gels with only atomically dispersed Pb sites result in the ideal combination of high response and short recovery time, leading to a highperformance room-temperature p-type semiconductor NO2 gas sensor with a combination of ultra-low LOD (3 ppb), high sensitivity (0.06%/ppb), short tres (~28 s), and trec (~60 s). Density functional theory (DFT) calculations suggest that the high performance of the PbxCd1−xSe QD gel is caused by the unique tuning effects of atomically dispersed Pb ionic sites on NO2 binding at their neighboring Cd sites

Methods

Results

Conclusion