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Lead-free thin film capacitors, simultaneously possessing a large energy storage density, ultrahigh efficiency and an extra wide working temperature range, are desirable in applications. In this work, A2Bi4Ti5O18 (A = Ba and Sr) thin films were successfully deposited onto Pt/Ti/SiO2/Si by chemical solution deposition. A large energy storage density (Ure) of 37.1 and 17.2 J cm−3 and a high efficiency (η) of 91.5% and 80.8% were achieved in Ba2Bi4Ti5O18 and Sr2Bi4Ti5O18 thin films, respectively. Moreover, these two thin films show excellent thermal abilities under an extra wide working temperature range from −100 °C to 180 °C. Additionally, high cycling fatigue endurance with a variation of the energy storage density of less than 3.7% and efficiency less than 2.1% after 2 × 108 charge–discharge cycles is obtained for these two thin films. These results indicate that A2Bi4Ti5O18 thin film capacitors have strong potential applications in equipment in harsh working environments.

We show for the first time that a magnetic field can act as an independent parameter to accelerate the Kirkendall effect in a liquid reaction system. By taking silicon-based nanospheres as a model, it was demonstrated that a magnetic field could efficiently reduce the time of the Kirkendall effect processes at relatively low reaction temperatures. The hollow structure of the product obtained after 5 h under a magnetic field of 1 T is the same as that obtained after 24 h without a magnetic field.

Recent progress in transparent conducting components stimulates the extensive exploration of p-type transparent conducting oxide (TCO) materials. Here, we report the synthesis of a class of p-type delafossite Ag-based TCO thin films, AgCrO2 (ACO), using a facile chemical solution route in an open condition. Firstly, the evolution of microstructure, morphology, and optical properties with respect to annealing temperature is reported. The stoichiometric ACO thin films show self-assembled c-axis orientation. The 500 °C-annealed ACO thin film presents a relatively high quality, dense surface and good optical transmittance amongst all the derived thin films. Then, to improve the conductivity, Mg doping effects are investigated. Upon Mg doping, p-type conductivity is obtained for thin films of AgCr1−xMgxO2 (0.04 ≤ x ≤ 0.20). The conductivity initially increases from 3.1 × 10−3 to 67.7 × 10−3 S cm−1 with x increasing from 0.04 to 0.12 and then slightly decreases with further increasing Mg concentration. The Hall results display that the hole concentration gradually increases with increasing Mg dopant concentration, and the carrier mobility first increases with x increasing from 0.04 to 0.12, while decreases with x further increasing from 0.12 to 0.20. A high magnitude of optical transmittance near 60% in the visible region and wide optical bandgaps (3.41–3.66 eV) of the AgCr1−xMgxO2 thin films are observed. The facial fabrication of ACO thin films in an open condition will provide a start for the synthesis of Ag-based delafossite thin films.

Multiferroic BiFeO3 (BFO) thin films with a thickness larger than 400 nm are grown on solution-derived LaNiO3 coated Si substrates via chemical solution deposition. The prepared BFO/LaNiO3/Si thin films are strongly (00l)-oriented with a distorted rhombohedral structure of R3c symmetry. The effects of the annealing temperature within the temperature range of 500–650 °C on the microstructures and properties are investigated. With an annealing temperature increasing to 600 °C, the (00l) orientation is enhanced and the grain size is increased, whereas a higher annealing temperature will lead to the deterioration of the orientation and microstructures. The annealing temperature dependent dielectric, leakage and ferroelectric properties are investigated, showing excellent properties for the low temperature annealed BFO thin films. The mechanisms about annealing temperature effects are discussed. The results will provide an effective route to realize the integration of large-area BFO thin films on Si wafers by an all-solution approach with low cost.

As the most-studied multiferroic material, (111)-oriented BiFeO3 (BFO) thin films are desirable due to the highest polarization in the (111) plane. The difficulty of achieving large-area (111)-oriented BFO films on silicon wafers towards implementation with silicon technology has hindered the development of BFO films. Herein, we report the annealing temperature effects on chemical solution deposition (CSD) derived BFO films on Pt(111)/Ti/SiO2/Si substrates without any buffer layer. The derived BFO films shows a strong (111) orientation with a distorted rhombohedral structure and R3c space group. The annealing temperature effects on the microstructures as well as the properties were investigated. A dense and crack-free surface was obtained in the low-temperature annealed films. Relatively high room-temperature remnant polarization 2Pr (120–140 μC cm−2) could be obtained with low leakage (∼10−5 A cm−2 at 200 kV cm−1). Scanning electron microscopy and transmission electron microscopy showed that this is an available route for fabricating large-area (111)-oriented BFO films on silicon-based wafers with high 2Pr using low-cost solution processing.

In this paper, Bi2Sr2Co2Oy and Bi2Ba2Co2Oy thin films were prepared on Ca3Co4O9/polycrystalline Al2O3 thin films by chemical solution deposition. The results show that both of the bismuth-based cobaltate thin films are self-assembled c-axis oriented, which confirms that Ca3Co4O9/polycrystalline Al2O3 thin film can be used as an effective template to induce c-axis oriented grain growth in layered cobaltate thin films. The annealing temperature effects on Bi2Sr2Co2Oy thin films were investigated, and the resistivity and Seebeck coefficient decrease with the increasing annealing temperature. The results will provide an effective template to realize self-assembled c-axis oriented layered cobaltate thin films on polycrystalline substrates by chemical solution deposition.

Preparation of antiperovskite thin films is challenging work due to their complex phase diagram and easy decomposition during processing, which hinder the fundamental studies and applications. Herein, we report the preparation of antiperovskite CuNCo3 (CNC) thin films on several different single crystal substrates by chemical solution deposition. The results show that the derived CNC thin films are c-axis oriented regardless of the substrate orientation, suggesting the self-assembled c-axis orientation. The microstructures as well as the physical properties are investigated, showing that the CNC thin films are metallic and can be considered as a new type of soft-magnet with a ferromagnetic Curie temperature higher than 650 K. The results will provide an effective route for fabricating antiperovskite cobalt-based thin films as well as provide a prototype for the investigation of the growth mechanisms of complex metal nitride thin films by solution methods.

In this work, BiFeO3 (BFO) thin films were prepared on metallic Ni (200) tapes with and without a La0.5Sr0.5TiO3 (LSTO) buffer layer at different temperatures by chemical solution deposition. The effects of the annealing temperature as well as the LSTO buffer layer on the dielectric, leakage and ferroelectric properties have been studied in detail. The crystallite size, dielectric constant and leakage current density increase, while the coercive field decreases with increasing annealing temperature. The BFO thin films deposited directly on the Ni tapes are prone to wrinkling, while the wrinkles are smoothed by introducing a thin LSTO buffer layer. Decreased compressive microstrain as well as improved ferroelectric and leakage properties are observed in the BFO thin films deposited on the LSTO buffered Ni tapes. The results will provide an instructive route to optimize BiFeO3-based thin films on metallic tapes by chemical solution deposition methods.

CrN thin films are first prepared by a facile chemical solution deposition method. The results show that the derived CrN thin films are nanocrystalline with the grain size of 30–60 nm. X-ray photoelectron spectroscopy measurement shows the stoichiometry of the derived thin film. The temperature dependent resistivity within the range of 2–300 K shows a semiconductor-like behavior with dρ/dT < 0 and a discontinuity in resistivity at 253 K is observed due to the antiferromagnetic transition. At 10 K the magnetoresistance is as low as −0.06% under 45 kOe. The first growth of CrN thin films by the facile chemical solution deposition will provide an alternative route to prepare CrN thin films, especially for large-area CrN thin films with low-cost.

Transparent conducting p-type Bi2Sr2Co2Oy thin films have been first grown on SrTiO3 substrates by a chemical solution deposition, showing c-axis self-orientation. The figure of merit can reach as high as 800 MΩ−1, which is the highest value for p-type transparent conducting thin films by solution methods.

Bi(2)Sr(3)Co(2)O(y) thin films are prepared on SrTiO(3) (100), (110) and (111) single crystal substrates using the sol-gel method. All the thin films are c-axis oriented regardless of the orientation of the substrate suggesting self-assembled c-axis orientation, and X-ray photoelectron spectroscopy results give evidence of coexistence of Co(3+) and Co(2+) ions in the derived films. Transmission electronic microscopy observations reveal that all samples are c-axis oriented with no obvious differences for different samples, and the c-axis lattice constant is determined as ~15 Å suggesting the misfit structure. A phenomenological thermodynamic phase diagram for self-assembled c-axis orientation is established for misfit cobaltate-based films using chemical solution deposition. All samples behave like semiconductors due to the coexistence of Co(3+)/Co(2+) ions, and the resistivity at 350 K is ~47, 39 and 17 mΩ cm for the thin films on SrTiO(3) (100), (110) and (111), respectively, whereas the Seebeck coefficient at 300 K is 97, 89 and 77 μV K(-1). The successful attainment of Bi(2)Sr(3)Co(2)O(y) thin films with self-assembled c-axis orientation will provide an effective prototype for investigation of growth mechanisms in complex oxide thin films with a misfit structure.