Flexible dye-sensitized solar cells (FDSSCs) have good potential in future photovoltaic technology. The spin coating method deposited the ZnO films on indium-tin-oxide-coated polyethylene terephthalate (ITO-PET) flexible plastic substrates. These films are implanted with Cu-ions with 1 × 1013 ions/cm2, 1 × 1014 ions/cm2, and 1 × 1015 ions/cm2. All the films have a hexagonal structure. The film irradiated with 1 × 1014 ions/cm2 showed high crystallinity and crystallite size. Important optical properties like bandgap energy (Eg), band edges, refractive index, extinction coefficient, and dielectric constants are measured by UV–Vis spectroscopy. Bandgap energy decreases, and the refractive index increases at the fluence of Cu ions. The maximum decrease in Eg is observed at the 1 × 1014 ions/cm2 dose. Photoluminescence spectra suggest that defects-related emission peaks are decreased at 1 × 1014 ions/cm2 Cu ions fluency. J-V measurements have significantly improved photovoltaic performance compared to pristine ZnO-based solar cells. The highest efficiency (2.30%) is observed at a 1 × 1014 ions/cm2 dose. The efficiency increase is related to improving the charge transfer ratio and shifting the fermi level toward the conduction band. 相似文献
A metallurgical evaluation of a FeCrAlMo alloy was carried out after observing low temperature fracture in several purge lines made of this material. The unexpected material embrittlement was attributed to high temperature phase transformations occurred during a previous exposure of the components at 800 °C. The microstructural analysis showed extensive Mo-rich precipitates and Cr-rich carbides at grain boundaries associated with the failed components. The study also showed by means of compression tests carried out at room temperature evident loss of ductility in the samples exposed at high temperatures as a consequence of the material aging. 相似文献
The effect of Cr content on the microstructure and cyclic oxidation behavior of Nb–10W–XCr alloys with four different compositions has been investigated. Experiments were conducted in air at 900 °C and 1300 °C; the oxidation kinetics have been evaluated in terms of weight change per unit area with respect to exposure time. Alloy's microstructure consists of Nb solid solution phase regions surrounded by a network of NbCr2 Laves phase. A trend of improvement in oxidation resistance with increase of the intermetallic phase is observed at 1300 °C and oxidation kinetics follow a parabolic behavior. At 900 °C, alloys with higher Cr content exhibit higher oxidation rates than alloys with lower Cr content. The oxidation products are a mixture of CrNbO4, and Nb2O5 and the amount of each oxide present in the mixture is related to the intermetallic phase content. Results delineate the influence of microstructure and composition on the oxidation mechanisms of these alloys that represent a promising base for high-temperature intermetallic alloy development. 相似文献
Microstructure and crystal orientation distribution of two-phase NiAl(β)/Ni3Al(γ′) alloys obtained by thermomechanical processing were investigated. Cylindrical Ni-36 and 38 at.%Al alloy single crystals with various initial loading axes were hot-compressed at a high strain rate of 1.0 s−1 and subsequently annealed in the (β/γ′) two-phase region. After the hot deformation, relatively uniform subgrain structures were formed in initial 〈111〉β-oriented crystals, while a number of deformation bands perpendicular to the compressive axis developed in 〈100〉β-, 〈110〉β- and 〈123〉β-oriented crystals. Two types of deformation bands with different crystal orientations were alternately arranged against the compressive axis. After annealing in the (β/γ′) two-phase region, a film-shaped γ′ phase with peculiar variants of the Kurdjumov–Sachs orientation relationship preferentially precipitated along the boundary between the deformation bands, resulting in the formation of a (β/γ′) two-phase lamellar structure. Formation process of the deformation bands in β phase and the crystallography of γ′ precipitates along deformation bands were discussed. 相似文献
Implementing pressure-assisted flash sintering of ZnO powder without pretreatment by a new experimental configuration is presented. Rapid and energy-concentrated heating of electrode-sample-electrode area by induction heating allows preheating and flash sintering of loose-pack powder in the die with pressure assistance. Using an insulated die enables the current to flow through the sample during flash sintering. ZnO ceramics with a relative density of 95.1% can be achieved in less than 3 min. The whole process includes 104 s of preheating by a low-power induction heating device and 30 s of flash sintering assisted by a pressure of 26 MPa using the pulsed direct current (DC). The process characteristics of pressure-assisted flash sintering using the pulsed DC are discussed. The effect of pressure on densification and grain size is analyzed in detail, and some potential mechanisms are provided. 相似文献
??The tensile creep of HT9 steel was measured at 700 and 800?? with different stress levels. Stress exponent was fitted by power law relation. Rupture time vs. minimum creep rate of HT9 steel was fitted by M- G relationship and modified M- G relationship. The fracture morphology after creeping and the creep mechanism and damage mechanism were analyzed by scanning electron microscopy, transmission electron microscopy and X- ray diffraction. The results showed that the minimum creep rate and creep rupture time of HT9 steel obeyed a linear relationship with the stress in double logarithmic coordinates, which could be described by M- G and modified M- G relationship. The stress exponent increased with the temperature. The dislocations bypassed the second phase particles during the creep process according to the Orowan mechanism. The fracture had a distinct dimple structure, and some of the second phase particles coarsened. The oxidation of HT9 steel was obvious during the creep at 800??. The main precipitates were M23C6 during the creep, which showed different forms, with significant differences in the size of the precipitated phases. The damage mechanism of HT9 steel included external cross- sectional area loss, material microstructure degradation, environmental damage, etc. There may also be internal sectional area loss. 相似文献
In the present work, Tungsten (W)/oxide dispersion strengthened (ODS) steel joints were fabricated by the direct solid state diffusion bonding (SSDB) technology with a multistage cooling process, and the microstructure and tensile strength of the bonded interfaces and parent materials were experimentally investigated. The results show that W and ODS steel can be successfully bonded at the temperature ranging from 900 °C to 1050 °C, without severe macroscopic deformation or obvious microscopic defects. Reaction layers generated at the bonded interfaces are evolutive with the bonding temperature, result in different fracture locations of the bonded joints. In the joint bonded at 950 °C, a higher interfacial strength of ~ 234.2 MPa is achieved, due to the formation of nano-scale intermetallic compound FeW. Microstructure of W remains stable after all the SSDB processes, while the lath structure of ODS steel is completely broken and transformed into the equiaxed grains, which should be responsible for the deterioration of strength. When the bonding temperature is higher than 950 °C, the pinning effect of precipitates M23C6 and nano-oxide particles on the movement of dislocations is observed.