In this work, an alternative route to fabricating high-quality CH₃NH₃PbI₃ thin films is proposed. Single-source physical vapour deposition (SSPVD) without a post-heat-treating process was used to prepare CH₃NH₃PbI₃ thin films at room temperature. This new process enabled complete surface coverage and moisture stability in a non-vacuum solution. Moreover, the challenges of simultaneously controlling evaporation processes of the organic and inorganic sources via dual-source vapour evaporation and the heating process required to obtain high crystallization were avoided. Excellent composition with stoichiometry transferred from the powder material, a high level of tetragonal phase-purity, full surface coverage, well-defined grain structure, high crystallization and reproducibility were obtained. A PCE of approximately 10.90% was obtained with a device based on SSPVD CH₃NH₃PbI₃. These initial results suggest that SSPVD is a promising method to significantly optimize perovskite CH₃NH₃PbI₃ solar cell efficiency.

In this work, halide ion diffusion in lead-free halide double perovskites Cs ₂ AgBiX ₆ (X = Cl, Br), Cs ₂ AgSbCl ₆ and Cs ₂ AgInCl ₆ was investigated by first-principles calculations.

In this work, solvent annealing process for CH₃NH₃PbI₃ thin film prepared by single source evaporation was reported. Characterized by the scanning electron microscope (SEM), X-ray diffractometer (XRD), energy dispersive spectroscope (EDS), ultraviolet-visible (UV) spectrophotometer, and the photoluminescence (PL) spectrometer, our method ensured higher quality film with crystallinity, composition, well-defined grain structure, and reproducibility. The optimized solar cell device based on the structure of ITO/PEDOT:PSS/CH₃NH₃PbI₃/PCBM/Ag achieved better performance in power conversion efficiency from 2.64% to 9.92%, providing an effective method to optimize the quality of perovskite film for solar cell application.

Two-dimensional transition metal dichalcogenides are considered promising materials for next-generation photonics and nano-optical devices. Although many previous reports have shown saturable absorption of molybdenum diselenide (${\mathrm{MoSe}}_2$), these nonlinear optical (NLO) properties of ${\mathrm{MoSe}}_2$ were measured in separate works and under different conditions with their hot-carrier relaxations. Here, we conducted a series of coherent studies on the NLO properties of few-layer ${\mathrm{MoSe}}_2$ via open-aperture $Z$-scan and degenerate pump-probe techniques. These measurements were taken to test the materials’ capabilities as a slow-saturable absorber. A slow-absorber model was employed to analyze the NLO measurements, and the results show that the NLO modulation depth was modeled to be 7.4% and 15.1% for the linear absorption coefficients of $5.22{\mathrm{cm}}^{-1}$ and $6.51{\mathrm{cm}}^{-1}$, respectively. The corresponding saturated intensities were modeled to be $39.37\mathrm{MW}/{\mathrm{cm}}^2$ and $234.75\mathrm{MW}/{\mathrm{cm}}^2$, respectively. The excitation carrier recovery time of few-layer ${\mathrm{MoSe}}_2$ was measured by degenerate pump-probe techniques to be $\sim 220\mathrm{ps}$. These nonlinear optical performances make it a promising slow-saturable absorber for passive mode locking in femtosecond lasers.

In this work, using a conventional magnetron sputtering system, Al-doped ZnO (AZO) films with (110) and (0002) preferential orientations were grown on r-sapphire and a-sapphire substrates, respectively. The effect of substrate and deposition temperature on the growth of AZO films and their preferential orientations were investigated. The crystallographic characteristics of AZO films were characterized by X-ray diffraction (XRD). The surface morphology of AZO films was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). It is found that the lattice mismatch between AZO and substrate determines the growth of AZO films and their preferential orientations. The thermoelectric properties are strongly dependent on the crystal grain shape and the grain boundaries induced by the preferred orientation. The highly connected and elongated grains lead to high thermoelectric properties. The in-plane anisotropy performances of thermoelectric characteristics were found in the (110) preferential oriented ZnO films. The in-plane power factor of the (110) preferential oriented ZnO films in the [0001] direction was more than 1.5 × 10⁻³ W m⁻¹ K⁻² at 573 K, which is larger than that of the (0002) preferential oriented ZnO films.