PbSe quantum dots-based chemiresistors for room-temperature NO2 detection

Abstract

2018) PbSe quantum dotsbased chemiresistors for room-temperature NO2 detection. Sensors and Actuators B: Chemical, 256. AbstractColloidal quantum dots (CQDs) are promising building blocks for low-cost and high-performance gas sensors due to their excellent solution processability and extremely small size. Among chalcogenide CQDs, PbSe has a large exciton Bohr radius and exhibits strong confinement energies, facilitating the fast charge-carrier transport. However, CQDs-based devices are susceptible to degrade due to the poor stability of CQDs. Here, in order to obtain air-stable PbSe CQDs for gas sensing application, we synthesized PbSe CQDs using a cation exchange method with in situ chloride and cadmium passivation. The sharp absorption peak in UV-vis absorption spectra confirmed strong quantum confinement in the PbSe CQDs and their average diameter was estimated to be 2.87 ± 0.23 nm. To construct gas sensors, PbSe CQDs were spin-coated onto ceramic substrates and then Pb(NO 3 ) 2 treatment was carried out to remove the long-chain ligands surrounding PbSe CQDs. At 25 °C, the sensor was highly sensitive and selective to NO 2 with a response of 22.3 at 50 ppm and a fast response time of 7 s. Moreover, the sensor response showed a 85.2% stability as the time increased up to 20 days, suggesting the potential applications of PbSe CQDs for NO 2 monitoring at room temperature.Highly sensitive gas sensors for detecting tiny amounts of toxic and hazardous gases play a vital role in our daily life for public safety, industrial processes, medical diagnosis, and continuous monitoring of environmental pollution [1,2]. To date, worldwide effort has been made to develop reliable gas sensors with high sensitivity and selectivity, and rapid progress has been achieved driven by the emerging nanoscience and nanotechnology [3][4][5].Recently, low-dimensional nanostructured materials with tailored structures have expressed great potential for serving as the sensing layer of gas sensors [6][7][8][9]. Their performance can be significantly enhanced through reducing the dimension of the gas-sensing materials. Specifically, zero-dimensional nanoparticles were extensively used to make gas sensors because of their unique electrical and optical properties. For example, Pd nanoparticles [10] were used in surface acoustic wave H 2 sensor, ZnO [11] and BaTiO 3 [12] nanoparticles were used for detection of formaldehyde and H 2 S, respectively. However, one of the major challenges faced in the development of nanoparticlebased gas sensors is the difficulty in obtaining various sizes of nanoparticles below 10 nm as well as the lack of precise control of their size distribution, because smaller particles are expected to have more gas adsorption sites.Colloidal quantum dots (CQDs), semiconductor nanoparticles synthesized and suspended in the solution phase, display certain merits due to their special structures and properties. First, being highly tunable material, CQDs possess flexible adjustability of sizes, with advantages of extremely small siz...

N-Doped Graphene Quantum Dot-Decorated Three-Dimensional Ordered Macroporous In2O3 for NO2 Sensing at Low Temperatures

“…Nitrogen dioxide (NO 2 ), released mainly from motor vehicle exhausts and fossil fuel combustion, is a common toxic and harmful gas . NO 2 emissions can not only lead to acid rain, which have severe negative impacts on water, terrestrial, and artificial ecosystem but also result in the formation of ground-level photochemical smog that is extremely harmful to human health. , Recent epidemiological studies have documented that the respiratory and cardiovascular systems of human will be damaged even if exposed to low concentrations of NO 2 . − Therefore, it is imperative to detect NO 2 concentration in the environment rapidly and precisely for protecting human health . However, quick and accurate detection of trace NO 2 in a complex environment remains a great challenge and has thus been the focus of ongoing research.…”

Lead sulphide colloidal quantum dots for room temperature NO2 gas sensors

“…The applicability of SnO 2 QDs based sensors to NO 2 10 , H 2 S 29 , ethanol 30 and LPG 31 , 32 detection has been demonstrated as well. Other relevant examples are a graphene QDs based sensor developed for NH 3 sensing 33 , PbSe QDs sensitive and selective to NO 2 34 and WO 3 QDs based sensor to detect H 2 S gas 35 .…”

“…The applicability of SnO 2 QDs based sensors to NO 2 10 , H 2 S 29 , ethanol 30 and LPG 31,32 detection has been demonstrated as well. Other relevant examples are a graphene QDs based sensor developed for NH 3 sensing 33 , PbSe QDs sensitive and selective to NO 2 34 and WO 3 QDs based sensor to detect H 2 S gas 35 . Despite the successful demonstration of several QDs based gas sensors, their performance has never been related to the geometrical characteristics of the proposed devices.…”

Nitric oxide sensors using nanospiral ZnO thin film deposited by GLAD for application to exhaled human breath

“…There is extensive research on developing sensitive and selective nitric oxide (NO x ) gas sensors for applications in the elds of high temperature combustion, environmental protection and clinical analysis. [1][2][3][4] In the clinical analysis application, nitrogen monoxide (NO) concentration in exhaled human breath is a biomarker for pulmonary inammation processes of the lower respiratory tract, e.g. asthma.…”