Fig. 2

Structure characterization of AlOOH. a Low-magnification TEM image of AlOOH nanosheets. b The corresponding element mapping of Al and O in AlOOH nanosheets. c AFM topography image of AlOOH film illustrating distribution and arrangement of AlOOH nanosheets in the film. d High-resolution TEM image showing the crystal lattice of AlOOH. The AlOOH crystal surface spacing is 0.63 nm, corresponding to the (0 2 0) crystal orientation. Inset: the corresponding FFT pattern. e XRD patterns of AlOOH film. f XPS analysis of AlOOH film. g O 1s core level spectra for the AlOOH film. h FTIR images of AlOOH film. i Transmittance spectra of Glass/AlOOH in the visible region; the CSU logo beneath the devices is clearly visible without any distortion owing to the excellent transparent properties of the device structure