Stability study of organometal halide perovskite and its enhanced X-ray scintillation from the incorporation of anodic TiO nanotubes.

Organometal halide perovskite-based optoelectronic devices are currently a hot research area owing to their unique properties, but widespread commercialization is plagued by their poor long-term stability. So far, the degradation mechanism of organometal halide perovskites is still indistinct due to limited real time systematic study. In this work, we study the crystal evolution of an organometal halide perovskite CHNHPbI, which is prepared on different kinds of framework substrates. Based on the grazing incidence X-ray diffraction and X-ray near absorption edge spectrum, we observe the formation of some 2D networks of [PbI] octahedra intermediates during CHNHPbI degradation in a moist environment at the early step of the degradation mechanism. We also show that the structural stability of CHNHPbI deposited anodic TiO nanotube substrates is relatively better than that of prepared perovskite on TiO nanoparticles in moisture. The confinement of the 3D [PbI] octahedral crystal network probability reduces the ion migration by regular pores of crystalline TiO nanotubes, improving the stability of the organometal halide perovskite. Furthermore, the X-ray excited luminescence intensity of CHNHPbI fabricated on TiO nanotubes is boosted 88% compared with that of conventional TiO nanoparticle substrates, which demonstrates its potential application in scintillation detectors.