| Popis: |
Two-dimensional covalent organic frameworks (2D COFs) are promising for gas sensing owing to the large surface area, size-tunable pores, abundant active sites, and their semiconducting nature. However, 2D COFs are usually produced in the form of insoluble micro crystallites. Their poor contacts between grain boundaries severely suppress the conductivity, which are too low for chemresistive gas sensing. Here, we demonstrate that halide perovskite nanocrystals can be employed as electric glues to bond 2D COF crystallites to significantly improve their conductivity by two orders of magnitude, activating them to detect NO2 with high selectivity and sensitivity. Resonant microcantilever (RMC), grand canonical Monte Carlo (GCMC), density functional theory (DFT) and sum-frequency generation (SFG) analyses prove that 2D COFs can enrich and transfer electrons to NO2 molecules, leading to increased device conductivity. Our work gives a new approach to improving the conductivity of 2D COF films and expands the applications of 2D COF micro crystallites. |
