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In this paper, quaternary oxide semiconductor was applied as sensing material for the fabrication of gas sensors. One-step solvothermal method was utilized to synthesize the sensing material. Various characterization methods including XRD, XPS, SEM, HRTEM were employed to analyze the composition and structure of the sensing material. Composite composed of CuInW2O8 and CuWO4 was successfully prepared at last characterized by XRD result. The SEM result revealed the structure of the sensing material: nanoparticles assembled spindle-like nanostructure with ~200 nm long axis and ~60 nm short axis. Sensor based on the spindle-like nanostructures was systemically tested to acquire the information about the sensing properties. The sensor exhibited responses to acetone at the operating temperatures from 190 to 275 °C. The results showed that the sensor was more sensitive to acetone compared with other gases at the optimal operating temperature of 210 °C. The response of the sensor was also tested under the relative humidity from 25 RH% to 95 RH% at the operating temperature of 210 °C. The response variation was only 13.9%, demonstrating that the sensor possessed strong anti-humidity ability. It was worth noting that the sensor showed acceptable long-term stability compared with other acetone sensors. The gas sensing mechanism was also discussed here. This work might provide ideas for the development of novel sensitive materials for the application of gas sensors.

A uniform CH3NH3PbI3 layer was successfully deposited on a mesoporous TiO2 layer (mp-TiO2) via a two-step low-voltage room-temperature electrochemical deposition method without annealing. The deposited perovskite crystals were applied to cover a surface mp-TiO2 electron transport material and fill the nanoscale blank of mp-TiO2. A mesoporous electron transport material and a platinum sheet were used as working and counter electrodes, respectively. The obtained film was then utilized to fabricate a mesoporous hybrid perovskite solar cell (PSC) with the configuration of a fluorine-doped tin oxide/compact TiO2/mp-TiO2/perovskite/Spiro-OMeTAD/Au electrode. An efficiency of 15% was achieved by adjusting Pb and MAI deposition and by using champion cells with an active area of 2 mm × 2 mm at 1 sun under an AM 1.5 condition. The perovskite layers and PSCs were analyzed through several characterization methods. Results demonstrated that this deposition technology could be applied to easily control the morphological characteristics of perovskite layers. Thus, a high power conversion efficiency was obtained. This study proposed a possible perovskite deposition process and demonstrated that electrochemical deposition could have potential for application in PSC fabrication.

A series of different facile modification layers (MLs) was designed to gradually increase the electrochemical sensing performance of glassy carbon electrode (GCE) for simultaneously detecting Pb2+ and Cu2+. ML designs were mainly a different combination of ZIF-67, MWCNT and Nafion, and their different electrochemical sensing performances were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), square wave stripping voltammetry (SWSV) and chronocoulometry. The fabricated sensor, which modified with ZIF-67/MWCNT and Nafion layer, exhibited the biggest response peak current to Pb2+ and Cu2+. In addition, it displayed a wide linear detection range of 1.38 nM–5 μM for Pb2+ and 1.26 nM–5 μM for Cu2+, a detection accuracy of about 1 nM for both Pb2+ and Cu2+, and an excellent stability for both Pb2+ and Cu2+. We also analyzed the real water sample taken from Changchun’s Sanjia Lake and Yan Lake. We believe this ML design provides instruction for building high-performance electrochemical sensing systems.

In this paper, the Pt/SnO2 nanostructures were prepared via a facile one-step microwave assisted hydrothermal route. The structure of the introduced Pt/SnO2 and its gas-sensing properties toward CO were investigated. The results from the TEM test reveal that Pt grows on the SnO2 nanostructure, which was not found for bulk in this situ method, constructing Pt/SnO2. The results indicated that the sensor using 3.0 wt% Pt/SnO2 to 100 ppm carbon monoxide performed a superior sensing properties compared to 1.5 wt% and 4.5 wt% Pt/SnO2 at 225 °C. The response time of 3.0 wt% sensor is 16 s to 100 ppm CO at 225 °C. Such enhanced gas sensing performances could be attributed to the chemical and electrical factors. In view of chemical factors, the presence of Pt facilitates the surface reaction, which will improve the gas sensing properties. With respect to the electrical factors, the Pt/SnO2 plays roles in increasing the sensor’s response due to its characteristic configuration. In addition, the one-step in situ microwave assisted process provides a promising and versatile choice for the preparation of gas sensing materials.

The sliver (Ag) modified zinc oxide (ZnO) nanorods were successfully obtained with a simplified and environmentally friendly solvothermal method. Materials characterization indicated that the metallic Ag was located on the outside of ZnO nanorods after annealing. In comparison with ZnO nanorods, Ag modified ZnO (Ag–ZnO) nanorods exhibited a considerably enhanced response to C2H2. The response of the 3 at% Ag–ZnO based sensor operating at 175 °C is 539 (Ra/Rg), which is the highest value among all the sensors in detecting 100 ppm C2H2. The Ag–ZnO based sensors exhibited fast response speed, lower operation temperature and higher selectivity.

Metal−organic frameworks (MOFs) with porous structures, high surface areas, diverse compositions, and functional linkers are promising materials and good carriers for building high-performance devices. In this work, uniform cobalt-doped ZnO nanoparticles (Co-doped ZnO NPs) derived from a MOF mold were synthesized, demonstrating the first example of synthesizing doped semiconductor metal oxide nanostructures using such strategy. The synthesis method produced Co-doped ZnO NPs that had a controllable doping mode, adjustable surface status, good dispensability, ferromagnetism and catalytic activity. The Co-doped ZnO NPs were evaluated as a sensing material for diabetes biomarker detection; the obtained sensors showed a high response to trace acetone (18.2 at 5 ppm), fast response/recovery times, a low detection limit (170 ppb), and long-term stability for 4 months. The enhanced sensing performance can be attributed to the increased number of active sites, additional impurity energy levels, and the catalytic ability of elemental Co. Moreover, the optimized sensor could distinguish between simulated diabetic breath and healthy human breath samples. The MOF-derived Co-doped ZnO NPs are a good candidate for the low-cost and noninvasive diagnosis of diabetes, and the proposed synthesis strategy can be extended to other types of extrinsically doped oxide materials.