P-type binary copper oxide semiconductor films for various O₂ flow rates and total pressures (P_t) were prepared using the reactive magnetron sputtering method. Their morphologies and structures were detected by X-ray diffraction, Raman spectrometry, and SEM. A phase diagram with Cu₂O, Cu₄O₃, CuO, and their mixture was established. Moreover, based on Kelvin Probe Force Microscopy (KPFM) and conductive AFM (C-AFM), by measuring the contact potential difference (V_CPD) and the field emission property, the work function and the carrier concentration were obtained, which can be used to distinguish the different types of copper oxide states. The band gaps of the Cu₂O, Cu₄O₃, and CuO thin films were observed to be (2.51 ± 0.02) eV, (1.65 ± 0.1) eV, and (1.42 ± 0.01) eV, respectively. The resistivities of Cu₂O, Cu₄O₃, and CuO thin films are (3.7 ± 0.3) × 10³ Ω·cm, (1.1 ± 0.3) × 10³ Ω·cm, and (1.6 ± 6) × 10¹ Ω·cm, respectively. All the measured results above are consistent.

A novel peeling process was introduced to effectively remove the harmful SnS ₂ secondary phase formed on the surface, which used a sticky tape without using any wet-chemical solution. Such a green surface treatment largely improved the performance of CZTS device.

In this paper, we adopt first-principles calculations based on density functional theory and kinetic Monte Carlo simulations to investigate the adsorption and diffusion of lithium in bilayer graphene (BLG) as anodes in lithium-ion batteries. Based on energy barriers directly obtained from first-principles calculations for single-Li and two-Li intercalated BLG, a new equation was deduced for predicting energy barriers considering ${\mathrm{Li}}^{{}^{\prime }}\mathrm{s}$ interactions for multi-Li intercalated BLG. Our calculated results indicate that Li energetically prefers to intercalate within rather than adsorb outside the BLG. Additionally, lithium exists in a cationic state in the BLG. More excitingly, ultrafast Li diffusion coefficient ($\sim {10}^{-5}{\mathrm{cm}}^2{\mathrm{s}}^{-1}$) within AB-stacked BLG near room temperature was obtained, which reproduces the ultrafast Li diffusion coefficient measured in recent experiment. However, ultrafast Li diffusion was not found within AA-stacked BLG near room temperature. The analyses of potential distribution indicate that the stacking structure of BLG greatly affects its height of potential well within BLG, which directly leads to the large difference in Li diffusion. Furthermore, it is found that both the interaction among Li ions and the stacking structure cause Li diffusion within AB-stacked BLG to exhibit directional preference. Finally, the temperature dependence of Li diffusion is described by the Arrhenius law. These findings suggest that the stacking structure of BLG has an important influence on Li diffusion within BLG, and changing the stacking structure of BLG is one possible way to greatly improve Li diffusion rate within BLG. At last, it is suggested that AB-stacked BLG can be regarded as an excellent candidate for anode material in lithium-ion batteries.