Novel in-situ embedded SnO₂-ZnO heterojunction for highly sensitive and selective gas sensors for lung cancer screening applications

The detection of n-propanol, a crucial biomarker for lung cancer in respiratory gases, is vital for the early diagnosis of this disease. Our research presents a novel approach to enhance n-propanol detection sensitivity through the synthesis of SnO₂-ZnO heterojunctions derived from ZIF-8. In this study, SnO₂ is in-situ embedded within the pores of ZnO obtained from ZIF-8, forming a heterojunction. This unique structure endows the SnO₂-ZnO heterojunctions with a large specific surface area and abundant active sites. Moreover, the formation of the in-situ embedded heterojunction significantly increases the adsorption energy of n-propanol on the material's surface while reducing the dissociation energy for oxygen, thereby improving gas-sensing performance. The in-situ embedded SnO₂-ZnO heterojunction sensor demonstrates remarkable sensitivity to n-propanol, with a response range of 128 to 20 ppm at an operating temperature of 200 °C. Notably, this method achieves an exceptionally low detection limit of 0.05 ppm, along with excellent selectivity and reliable stability. In addition, the sensing device can effectively differentiate between the expiratory breaths of simulated lung cancer patients and healthy individuals, offering promising opportunities for real-time, non-invasive detection of lung cancer. This advancement paves the way for future innovations in the early detection and diagnosis of lung cancer.