Background: Nowadays, lung diseases become more and more serious no only due to some dusty occupational environment but also the polluted atmosphere. Considering the latent period of lung diseases and the high difficulty of medical image for early screening, breath analysis shows a high potential for lung disease screening. Volatile organic compounds in breath changes according to pulmonary lesions, which could be detected by sensors.
Aim: To design a breath sensor for lung diseases detection with good sensitivity, response time and anti-interference.
Methods: Metal halide perovskite CsPbBr₃ is a promising sensing material due to high carrier mobility. However, perovskite easily reacts with the water vapor in breath. In this work, inorganic CsPbBr₃ quantum dots (QDs) were embedded into ZnO nanocrystals through a facile room-temperature in situ coating strategy for enhancing its gas response and water resistance (See Figure 1). During the in situ coating process, n-Octanoic acid was used as the buffer layer for reducing the lattice mismatch between CsPbBr₃ and ZnO.
Results: The perovskite CsPbBr₃/ZnO heterostructure not only worked at room temperature and moisture, but also displayed a normalized sensitivity (0.36) together with response time (36.5 s) and recovery time (5.3 s) towards 200 ppm heptanal. A low heptanal concentration (20 ppm) and good water resistance was detected by the sensor based on this material (See Figure 2 and 3). In contrast, no response was achieved in the sensors fabricated with the single CsPbBr₃ QDs or ZnO films.
Conclusions: Our study suggests that the metal halide perovskite embedded ZnO might play an essential role in detecting the biomarker of lung diseases.
 

Lung disease,breath tests,gas sensing,heptanal detection,quantum dots,perovskite material