Fig. 5: Characterization of the sensing mechanism.
From: Dimensional reduction in Cs2AgBiBr6 enables long-term stable Perovskite-based gas sensing
a The charge difference density of adsorption of CO on BA4AgBiBr8 (200) surface. The electron accumulation and depletion are represented with yellow and cyan contours, with iso-surfaces being 0.003 e/Å3. The black, white, purple, yellow, green, and pink balls refer to C, H, N, Bi, Ag, and Br atoms, respectively. Corresponding atomic coordinates are available in Supplementary Data 1. b Sum frequency generation (SFG) spectra of (BA)4AgBiBr8 film before and after CO adsorption. c The Electron Localization Function (ELF) diagram for adsorption of CO on BA4AgBiBr8 surface. The black, white, purple, yellow, green, and pink balls refer to C, H, N, Bi, Ag, and Br atoms, respectively. Corresponding atomic coordinates are available in Supplementary Data 2. d The Crystal Orbital Hamilton Population (COHP) and the corresponding Integrated Crystal Orbital Hamilton Population (ICOHP) value for C-Bi bond in the configuration of CO absorbed on BA4AgBiBr8 (200). The Fermi level (Ef) was set to 0.00 eV. e Total density of states (TDOS) of BA4AgBiBr8 (200) surface, and BA4AgBiBr8 (200) surface with CO molecule. The Ef is set to 0.00 eV. f Projected density of states (PDOS) of 6p orbitals of Bi in the BA4AgBiBr8 (200) surface with a CO molecule absorbed and Bi in the clean BA4AgBiBr8 (200) surface. The Ef is set to 0.00 eV. g PDOS of p orbitals of a CO molecule on the BA4AgBiBr8 (200) surface and an isolated CO molecule. The Ef is set to 0.00 eV. The insets are the partial charge densities with isosurface level set to 0.02 e/Å. The electron accumulation is represented with yellow contour. Source data are provided as a Source Data file.
