In-situ synthesis of stable ZnO-coated CsPbBr3 nanocrystals for room- temperature heptanal sensors

In this work, we coated perovskite quantum dots (CsPbBr3) with metal oxide (ZnO) by an in-situ oxidation strategy to obtain CsPbBr3@ZnO nanocrystals, which effectively improved the moisture sta-bility of the perovskite material. In addition, the ZnO layer can also transfer the interaction with gas molecules to the inner CsPbBr3, giving the CsPbBr3@ZnO nanocrystals good gas-sensing properties at room temperature. This study considered CsPbBr3@ZnO films' structural, morphological, and gas sensing properties; and simulated breath monitoring tests. Later a sensor based on CsPbBr3@ZnO nanocrystals was prepared and used to detect the presence of heptanal (a breath biomarker for lung cancer and COVID-19) in different gases, including air, artificial breath, and real breath. The sensor displayed a fairish sensitivity (S 1/4 0.36) alongside a brief response/recovery time (36.5 s/5.3 s) towards 200 ppm heptanal prepared with air, and the limit of detection could reach up to 2 ppm in the air and 3 ppm in artificial breath (made up of air, ethanol, isopropanol, 7-tridecanone, and n-tetradecane). Furthermore, the intelligent classification algorithms were used to identified the real breath samples containing heptanal (1-5 ppm) with an 82.5% accuracy rate in simulated breath monitoring tests. Theory calculation results showed that the good response to heptanal was attributed to both the positive adsorption energy ( thorn 3 eV) and the increased lattice distortion induced by heptanal. These sensors show great potential to be an effective method for early detection and treatment of lung cancer and COVID-19 for a healthy and prolonged life. We believe that this research will open the door toward more stable and practical perovskite-based sensors.(c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

In this study, perovskite quantum dots (CsPbBr3) were coated with metal oxide (ZnO) using an in-situ oxidation strategy to enhance the moisture stability and gas sensing properties. The CsPbBr3@ZnO nanocrystals exhibited good sensitivity and a quick response/recovery time towards heptanal, a breath biomarker for lung cancer and COVID-19. Intelligent classification algorithms achieved high accuracy in identifying heptanal in simulated breath monitoring tests. This research holds promise for the development of stable and practical perovskite-based sensors.