No abstract

Due to its excellent thermal stability and high performance, inorganic cesium lead mixed halide (ABX3, where A = Cs, B = Pb, and X = I/Br) all‐inorganic perovskite solar cells (IPVSCs) have attracted much interest in optoelectronic applications. However, the film quality, enough absorption by desired film thickness, and nature of partial replacement of cations determine the stability of the CsPbI2Br perovskite films. Herein, a hot air method is used to control the thickness and morphology of the CsPbI2Br perovskite thin film, and the A‐site (herein, Cs+) cation is partially incorporated by rubidium (Rb+) cations for making the stable black phase under ambient conditions. The Rb cation‐incorporated Cs1−xRbxPbI2Br (x = 0–0.03) perovskite thin films exhibit high crystallinity, uniform grains, extremely dense, and pinhole‐free morphology. The fabricated device with its Cs0.99Rb0.01PbI2Br perovskite composition with poly(3‐hexylthiophene‐2,5‐diyl) as a hole‐transporting layer exhibits a power conversion efficiency (PCE) of 17.16%, which is much higher than that of CsPbI2Br‐based IPVSCs. The fabricated Cs0.99Rb0.01PbI2Br‐based IPVSC devices retain >90% of the initial efficiency over 120 h at 65 °C thermal stress, which is much higher than that of CsPbI2Br samples.

No abstract

Nanostructured titanium dioxide (TiO2) has a potential platform for the removal of organic contaminants, but it has some limitations. To overcome these limitations, we devised a promising strategy in the present work, the heterostructures of TiO2 sensitized by molybdenum disulfide (MoS2) nanoflowers synthesized by the mechanochemical route and utilized as an efficient photocatalyst for methyl orange (MO) degradation. The surface of TiO2 sensitized by MoS2 was comprehensively characterized by X-ray diffraction (XRD), Raman spectroscopy, Fourier transform–infrared spectroscopy (FT–IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), UV–vis diffuse reflectance spectroscopy (UV–vis DRS), photoluminescence spectroscopy (PL), Brunauer–Emmett–Teller (BET) surface area, and thermogravimetric analysis (TGA). From XRD results, the optimized MoS2–TiO2 (5.0 wt %) nanocomposite showcases the lowest crystallite size of 14.79 nm than pristine TiO2 (20 nm). The FT–IR and XPS analyses of the MoS2–TiO2 nanocomposite exhibit the strong interaction between MoS2 and TiO2. The photocatalytic results show that sensitization of TiO2 by MoS2 drastically enhanced the photocatalytic activity of pristine TiO2. According to the obtained results, the optimal amount of MoS2 loading was assumed to be 5.0 wt %, which exhibited a 21% increment of MO photodegradation efficiency compared to pristine TiO2 under UV–vis light. The outline of the overall study describes the superior photocatalytic performance of 5.0 wt % MoS2–TiO2 nanocomposite which is ascribed to the delayed recombination by efficient charge transfer, high surface area, and elevated surface oxygen vacancies. The context of the obtained results designates that the sensitization of TiO2 with MoS2 is a very efficient nanomaterial for photocatalytic applications.

Inorganic cesium lead halide perovskite (CsPbX 3 ) is a promising lightharvesting material to increase the thermal stability and the device performance as compared to the organic−inorganic hybrid counterparts. However, the photoactive stability at ambient conditions is an unresolved issue. Here, we studied the influence of Nb 5+ ions' incorporation in the CsPbI 2 Br perovskite processed at ambient conditions. Our results exhibited that 0.5% Nb-incorporated CsPb 1−x Nb x I 2 Br (herein x = 0.005) thin films show excellent uniformity and improved grain size because of the optimum concentration of Nb 5+ doping and hot-air flow. The improved grain size and uniform film thickness deliver a superior interface between the CsPb 1−x Nb x I 2 Br layer and the hole-transporting material. The fabricated all-inorganic perovskite solar cell (IPVSC) devices exhibited the Nb 5+ cation incorporation which enables decreased charge recombination, leading to negligible hysteresis. The champion device produces an open-circuit voltage (V OC ) as high as 1.317 V. The IPVSC device containing a CsPb 0.995 Nb 0.005 I 2 Br composition delivers the highest power conversion efficiency of 16.45% under a 100 mW cm −2 illumination and exhibits a negligible efficiency loss over 96 h in ambient conditions.