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Quasi‐2D perovskite quantum wells are increasingly recognized as promising candidates for direct‐conversion X‐ray detection. However, the fabrication of oriented and uniformly thick quasi‐2D perovskite films, crucial for effective high‐energy X‐ray detection, is hindered by the inherent challenges of preferential crystallization at the gas‐liquid interface, resulting in poor film quality. In addressing this limitation, a carbonyl array‐synergized crystallization (CSC) strategy is employed for the fabrication of thick films of a quasi‐2D Ruddlesden‐Popper (RP) phase perovskite, specifically PEA2MA4Pb5I16. The CSC strategy involves incorporating two forms of carbonyls in the perovskite precursor, generating large and dense intermediates. This design reduces the nucleation rate at the gas‐liquid interface, enhances the binding energies of Pb2+ at (202) and (111) planes, and passivates ion vacancy defects. Consequently, the construction of high‐quality thick films of PEA2MA4Pb5I16 RP perovskite quantum wells is achieved and characterized by vertical orientation and a pure well‐width distribution. The corresponding PEA2MA4Pb5I16 RP perovskite X‐ray detectors exhibit multi‐dimensional advantages in performance compared to previous approaches and commercially available a‐Se detectors. This CSC strategy promotes 2D perovskites as a candidate for next‐generation large‐area flat‐panel X‐ray detection systems. The carbonyl array‐synergized crystallization strategy is used to reduce the nucleation rate of solution‐processed quasi–2D perovskites and passivate vacancy defects at the same time. The resultant quasi‐2D perovskite film, boasting a thickness exceeding half a hundred micrometers, demonstrates a vertically oriented structure and a pure well‐width distribution, thereby exhibiting commendable efficacy for direct X‐ray detection.

This work demonstrates the fabrication, characterization, and energy storage capacity of high calcium-doped strontium titanate thick films (Sr 0.60 Ca 0.40 TiO 3 ) for the first time. The thick films were fabricated using the screen-printing technique and densified using uniaxial pressing. The effect of densification on the structural, morphological, and surface chemical compositional of the materials was studied. The densified thick film revealed a notable frequency stability of dielectric permittivity (ε′) ≈ 198 with a low dielectric loss tangent (tanδ) in the order of 10 − 3 between 100 Hz and 1 MHz and was characterized by slim P-E loops signifying its paraelectric nature. A high energy recovery density (U e ) of 4.1 J/cm 3 and a high energy efficiency of 96% were simultaneously reached.

This paper presents the results of the synthesis and evaluation of thick thermoelectric films that may be used for such applications as thermoelectric power generators. Two types of electrochemical deposition methods, constant and pulsed deposition with improved techniques for both N-type bismuth telluride (Bi2Te3) and P-type antimony telluride (Sb2Te3), are performed and compared. As a result, highly oriented Bi2Te3 and Sb2Te3 thick films with a bulk-like structure are successfully synthesized with high Seebeck coefficients and low electrical resistivities. Six hundred-micrometer-thick Bi2Te3 and 500-µm-thick Sb2Te3 films are obtained. The Seebeck coefficients for the Bi2Te3 and Sb2Te3 films are −150 ± 20 and 170 ± 20 µV/K, respectively. Additionally, the electrical resistivity for the Bi2Te3 is 15 ± 5 µΩm and is 25 ± 5 µΩm for the Sb2Te3. The power factors of each thermoelectric material can reach 15 × 10−4 W/mK2 for Bi2Te3 and 11.2 × 10−4 W/mK2 for Sb2Te3.

In this work, CuO-loaded tetragonal SnO2 nanoparticles (CuO/SnO2 NPs) were synthesized using precipitation/impregnation methods with varying Cu contents of 0–25 wt% and characterized for H2S detection. The material phase, morphology, chemical composition, and specific surface area of NPs were evaluated using X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller analysis. From gas-sensing data, the H2S responses of SnO2 NPs were greatly enhanced by CuO loading particularly at the optimal Cu content of 20 wt%. The 20 wt% CuO/SnO2 sensor showed an excellent response of 1.36 × 105 toward 10 ppm H2S and high H2S selectivity against H2, SO2, CH4, and C2H2 at a low optimum working temperature of 200 °C. In addition, the sensor provided fast response and a low detection limit of less than 0.15 ppm. The CuO–SnO2 sensor could therefore be a potential candidate for H2S detection in environmental applications.

For fabricating brazed inserts in machining difficult-to-machine materials, chemical vapor deposition (CVD) diamond thick films are potential candidates for polycrystalline diamond (PCD). In the present study, monolayer microcrystalline diamond (MCD), monolayer nanocrystalline diamond (NCD), and multilayer diamond thick films were respectively deposited on the Si 3 N 4 substrates by the high-power density (HPD) microwave plasma CVD (MPCVD) technique, which were then brazed on WC–Co. Their microstructures, growth rates, and film quality were systematically studied. Within the multilayer film, in order to enhance the secondary nucleation on as-deposited MCD layers and promote the consecutive growth of NCD layers, increasing the nitrogen addition level was much more effective than increasing the methane/hydrogen ratio. The NCD interpositions could guarantee layer thickening, while suppressing the growing up of individual micro diamond grains. As revealed by Raman spectra, the multilayer structure could help restrain the accumulation of the residual stress with increasing the thickness. Besides, the multilayer diamond thick film also presented much enhanced erosive wear resistance, as compared with the monolayer MCD or NCD, because the NCD interlayers could prevent intergranular cracks from further propagating. Finally, cutting performances of various brazed inserts were evaluated, in the case of dry-turning the high-silicon aluminum alloy (40 wt.% Si), demonstrating that the multilayer structure could result in the enhancement of the impact toughness of cutting edges, and improve the machining quality.

Lead zircon titanate (PZT) composite films were advantageously prepared by a novel hybrid method of sol-gel and electrohydrodynamic jet (E-jet) printing. PZT thin films with thicknesses of 362 nm, 725 nm and 1092 nm were prepared on Ti/Pt bottom electrode via Sol-gel method, and then the PZT thick films were printed on the base of the PZT thin films via E-jet printing to form PZT composite films. The physical structure and electrical properties of the PZT composite films were characterized. The experimental results showed that, compared with PZT thick films prepared via single E-jet printing method, PZT composite films had fewer micro-pore defects. Moreover, the better bonding with upper and lower electrodes and higher preferred orientation of crystals were examined. The piezoelectric properties, dielectric properties and leakage currents of the PZT composite films were obviously improved. The maximum piezoelectric constant of the PZT composite film with a thickness of 725 nm was 69.4 pC/N, the maximum relative dielectric constant was 827 and the leakage current was reduced to 1.5 × 10−6A at a test voltage of 200V. This hybrid method can be widely useful to print PZT composite films for the application of micro-nano devices.

The piezoelectric thick film of the active component that works at high temperatures for space and aeronautics has been in significant demand. The thick film has great technological importance as its thickness lies between the thin film and bulk material. The application, such as sensors and actuators, require a thickness that is not less than thin film or not more than bulk to be sufficiently powerful and sensitive. While the thick film is exposed to a temperature higher than room temperature, the piezoelectricity and elastic properties should not be degraded. Thus researchers have been investigating high-temperature thick films for the past decade. This review focuses on the detailed study of high-temperature piezoelectric thick films of lead-based and lead-free based materials and their composites, highlighting fabrication methods. Other important areas, such as substrates for thick film properties achieved and targeted applications, are also discussed. This discussion shows that selecting the high-temperature piezoelectric material, fabrication method, substrates, etc., are essential for fabricating a high-temperature piezoelectric transducer.

This paper is focused on the study of internal stress in thick films used in hybrid microelectronics. Internal stress in thick films arises after firing and during cooling due to the differing coefficients of thermal expansion in fired film and ceramic substrates. Different thermal expansions cause deflection of the substrate and in extreme cases, the deflection can lead to damage of the substrate. Two silver pastes and two dielectric pastes, as well as their combinations, were used for the experiments, and the internal stress in the thick films was investigated using the cantilever method. Further experiments were also focused on internal stress changes during the experiment and on the influence of heat treatment (annealing) on internal stress. The results were correlated with the morphology of the fired thick films. The internal stress in the thick films was in the range of 8 to 21 MPa for metallic films and in the range from 12 to 16 MPa for dielectric films. It was verified that the cantilever method can be successfully used for the evaluation of internal stress in thick films. It was also found that the values of deflection and internal stress are not stable after firing, and they can change over time, mainly for metallic thick films.

The direct growth of ferroelectric films onto flexible substrates has garnered significant interest in the advancement of portable and wearable electronic devices. However, the search for an optimized bottom electrode that can provide a large and stable remnant polarization is still ongoing. In this study, we report the optimization of an oxide-based LaNiO3 (LNO) electrode for high-quality Pb(Zr0.52Ti0.48)O3 (PZT) thick films. The surface morphology and electrical conductivity of sol-gel-grown LNO films on a fluorophlogopite mica (F-mica) substrate were optimized at a crystallization temperature of 800 °C and a film thickness of 120 nm. Our approach represents the promising potential pairing between PZT and LNO electrodes. While LNO-coated F-mica maintains stable electrical conductivity during 1.0%-strain and 104-bending cycles, the upper PZT films exhibit a nearly square-like polarization–electric field behavior under those stress conditions. After 104 cycles at 0.5% strain, the remnant polarization shows decreases as small as ~14%. Under flat (bent) conditions, the value decreases to just 81% (49%) after 1010 fatigue cycles and to 96% (85%) after 105 s of a retention test, respectively.