Herein,viathe first-principles density functional theory, CASTEP code, we investigated the 15 vibrational normal modes of ferroelectric hydrogen-ordered phase of ice Ic and the two peaks of hydrogen bond are clarified.
Here, we choose (C 4 H 9 NH 3 ) 2 PbI 4 to represent the two-dimensional layered hybrid organic−inorganic perovskites and investigate its excellent moisture resistance by theoretical analyses. (C 4 H 9 NH 3 ) 2 PbI 4 adsorbs H 2 O molecules easily on all surfaces. However, the most energetic surface, i.e., C 4 H 9 NH 3 -terminated surface, provides an energy barrier of 3.46 eV to prevent the penetration of H 2 O molecules, which is 1 order higher than the barrier in MAPbI 3 surface. This obstacle for the invasive H 2 O molecule comes from the methyl/ methylene radicals of C 4 H 9 NH 3 groups. These methyl/methylene radicals are chemically inactive and only generate repulsive interactions with the H 2 O molecule, leading to the outstanding moisture resistance of (C 4 H 9 NH 3 ) 2 PbI 4 . Herein, we propose a practical strategy to obtain good moisture-resistant perovskite solar cell materials, i.e., modulate the shape and symmetry of organic molecules in perovskites to let as many methyl radicals as possible prevent the penetration of adsorbed H 2 O molecules from the surface.
Nitrogen-doped indium tin zinc oxide (ITZO:N) thin film transistors (TFTs) were deposited on SiO2 (200 nm)/p-Si〈1 0 0〉 substrates by RF magnetron sputtering at room temperature. The structural, chemical compositions, surface morphology, optical and electrical properties as a function of the active layer thickness were investigated. As the active layer thickness increases, Zn content decreases and In content increases gradually. Meanwhile, Sn content is almost unchanged. When the thickness of the active layer is more than 45 nm, the ITZO:N films become crystallized and present a crystal orientation along InN(0 0 2) plan. No matter what the thickness is, ITZO:N films always display a high transmittance above 80% in the visible region. Their optical band gaps fluctuate between 3.4 eV and 3.62 eV. Due to the dominance of low interface trap density and high carrier concentration, ITZO:N TFT shows enhanced electrical properties as the active layer thickness is 35 nm. Its field-effect mobility, on/off radio and sub-threshold swing are 17.53 cm2 V−1 · s−1, 106 and 0.36 V/dec, respectively. These results indicate that the suitable thickness of the active layer can enhance the quality of ITZO:N films and decrease the defects density of ITZO:N TFT. Thus, the properties of ITZO:N TFT can be optimized by adjusting the thickness of the active layer.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.