Search

Single-chamber solid oxide fuel cell made of conventional materials with two gas tubes located at the different sides of the cell was fabricated and tested in a diluted methane-oxygen mixture to evaluate the influence of various operating parameters on cell performance. The traditional gas supply method was also studied for comparison. Experimental results showed that the cell performance was greatly enhanced by using the dual gas supply method. At a furnace temperature of 700 °C, the maximum power density was 459.2 mW cm−2 for a CH4/O2 ratio of 1.5, which was 67% higher than that of the traditional gas supply method. Additionally, the dual gas supply method could provide the required reactant gas for each electrode by changing the gas composition of both the gas tubes separately. The highest power density of 493.9 mW cm−2 was obtained at the anode and cathode CH4/O2 ratios of 1.5 and 1, respectively. A cell with dual gas supply method will generate a more attractive power output than that of the traditional method in a single-chamber condition.

In this work, we focus on the optical super-resolution effect induced by strong nonlinear saturation absorption (NSA) of graphene oxide (GO) membranes. The third-order optical nonlinearities are characterized by the canonical Z-scan technique under femtosecond laser (wavelength: 800 nm, pulse width: 100 fs) excitation. Through controlling the applied femtosecond laser energy, NSA of the GO films can be tuned continuously. The GO film is placed at the focal plane as a unique amplitude filter to improve the resolution of the focused field. A multi-layer system model is proposed to present the generation of a deep sub-wavelength spot associated with the nonlinearity of GO films. Moreover, the parameter conditions to achieve the best resolution (∼λ/6) are determined entirely. The demonstrated results here are useful for high density optical recoding and storage, nanolithography, and super-resolution optical imaging.

Solution-processable, single-crystalline perovskite nanowires are ideal candidates for developing low-cost photodetectors, but their detectivities are limited due to a high level of unintentional defects. Through the surface-initiated solution-growth method, we fabricated high-quality, single-crystalline, defects-suppressed MAPbI 3 nanowires, which possess atomically smooth side surfaces with a surface roughness of 0.27 nm, corresponding to a carrier lifetime of 112.9 ns. By forming ohmic MAPbI 3 / Au contacts through the dry contact method, high-performance metal–semiconductor–metal photodetectors have been demonstrated with a record large linear dynamic range of 157 dB along with a record high detectivity of 1.2 × 10 14 Jones at an illumination power density of 5.5 nW / cm 2 . Such superior photodetector performance metrics are attributed to, first, the defects-suppressed property of the as-grown MAPbI 3 nanowires, which leads to a quite low noise current in the dark, and second, the ohmic contact between MAPbI 3 and Au interfaces, which gives rise to an improved responsivity compared with the Schottky contact counterpart. The realized high-performance MAPbI 3 nanowire photodetector advances the development of low-cost photodetectors and has potential applications in weak-signal photodetection.

Perovskites are widely used in various kinds of optoelectronic devices, including solar cells, photodetectors, light-emitting diodes, etc., due to their excellent properties such as long carrier diffusion length, high absorption coefficient, low trap state density and so on. Functional materials such as layered two-dimensional materials (graphene, transition metal dichalcogenides, etc.),low-dimensional semiconductor nanostructures (nanoparticles, quantum dots, nanowires, nanotubes,nanorods,nanopieces,etc.), metallic nanostructures(Au,Ag, etc.) and insulating materials (insulating polymer, organic amine, inorganic insulating film, etc.) have attracted more and more attention due to their special chemical, electrical and physical properties.In order to broaden the application of perovskites in photovoltaic devices, perovskites can be combined with various functional materials to form heterostructures so as to combine the advantages of the two types of materials.The heterostructures of perovskites/functional materials can be used as the interface modification layer in halide perovskites photovoltaic devices, to improve the crystallinity of perovskite, effectively reduce the surface defects and suppress the carrier recombination loss at the interface. The heterostructures of perovskites/functional materials can be used as the charge transporting layer in halide perovskites photovoltaic devices, can match well with the perovskite energy levels, which is beneficial to the efficient extraction of holes and electrons. The heterostructures of perovskites/functional materials also can be used as encapsulation layer in halide perovskites photovoltaic devices, to reduce the contact between water and perovskite, it can effectively prevent the degradation of perovskite, to improve the device stability.In addition, the semiconductor with narrow bandgap or array structure can be used to broaden the spectral response and to improve the light absorption of the perovskite photovoltaic devices.In a word, the heterostructures of perovskites/functional materials are applied to devices is an effective way to obtain high performance and low cost photovoltaic devices.In this review, recent works on the applications of the heterostructures in halide perovskite photovoltaic devices are comprehensively presented and discussed. The progress and advantages of the heterostructures as the interface modification layer, charge transporting layers and encapsulation layer in halide perovskite photovoltaic devices are systemically reviewed. Finally, we summarize the whole paper and give a prospect for the development of heterostructures based perovskite photovoltaic devices in the future.