Highly sensitive humidity sensor based on sub-micron level TiO2 flowers structure

In this study, we successfully synthesized TiO 2 micro-flowers (T-MFs) and investigated their performance in humidity sensing. The T-MFs possess a unique three-dimensional petal morphology with a large surface area and high crystallinity. The T-MFs-based humidity sensors demonstrated the highest sensor response of S R  ∼ 1 × 10 7 , significantly outperforming TiO 2 nano-discs (T-NDs) with S R  ∼ 1 × 10 5 , and TiO 2 nano-particles (T-NPs) with S R  ∼ 9 × 10 4 . These findings highlight the superior sensitivity of T-MFs-based sensors in terms of response, regardless of the humidity level. The sensors exhibit remarkable linearity (R 2  > 0.98), minimal hysteresis (0.4 %), and exceptional repeatability and reproducibility (verified through six cycles at 44 % RH and 90 % RH). Additionally, T-MFs showed long-term stability in aging tests conducted over 100 days at humidity levels ranging from 9 to 90 RH%. These results indicate that T-MFs have potential advantages in high-performance humidity sensing applications and provide new opportunities for the development of breath analyzers.