Preparation and electrochromic properties of flexible transparent WO3/AgNWs decorated nanofiber composite film

It is well-known that tungsten oxide (WO3) is extensively used for electrochromic (EC) devices due to their special properties such as high coloration/bleaching response time, good coloration efficiency and so on. The preparation of flexible EC devices is highly desirable for various applications. However, the fabrication of flexible EC devices with improved performance is still major task due to their limited experimental protocols. In this work, we have prepared thr highly flexible transparent films consisting of WO3 and silver nanowires coated on nanofiber-reinforced composite films (WO3/AgNWs-NCF). The novel flexible transparent WO3/AgNWs-NCF is used for the electrochromic (EC) applications. The as-fabricated EC device based on WO3/AgNWs-NCF demonstrated a good coloration efficiency (161.3 cm2/C), excellent stability (81.5 %), and rapid respone time for coloration (2.9 sec) and bleaching (3.2 sec). The fabricated transparent flexible EC device may be potentially useful to design an outstanding EC device for a smart window application.

The Room Temperature Highly Sensitive Ammonia Gas Sensor Based on Polyaniline and Nitrogen-Doped Graphene Quantum Dot-Coated Hollow Indium Oxide Nanofiber Composite

Hollow indium trioxide (In2O3) nanofibers fabricated via an effectively combined method of electrospinning and high-temperature calcination were coated with nitrogen-doped graphene quantum dots (N-GQDs) prepared by a hydrothermal process through electrostatic interaction. The N-GQD-coated hollow In2O3 nanofibers served as a core for the synthesis of polyaniline (PANI)/N-GQD/hollow In2O3 nanofiber ternary composites using in situ chemical oxidative polymerization. The chemical structure and morphology of the fabricated ternary composites were characterized using Fourier transform infrared, field-emission scanning electron microscopy, and transmission electron microscopy. The gas-sensing performances of the ternary composites were estimated by a homemade dynamic test system which was supplied with a real-time resistance acquisition platform at room temperature. The response value of the PANI/N-GQD/hollow In2O3 nanofiber sensor with a loading of 20 wt% N-GQD-coated hollow In2O3 nanofiber and an exposure of 1 ppm NH3 was 15.2, which was approximately more than 4.4 times higher than that of the PANI sensor. This ternary composite sensor was proved to be very sensitive in the detection of NH3 at a range of concentration between 0.6 ppm and 2.0 ppm at room temperature, which is crucial in the detection of hepatic or kidney disease in human breath. The PANI/N-GQD/hollow In2O3 nanofiber sensor also revealed higher selectivity and repeatability when exposed to 1.0 and 2.0 ppm NH3 at room temperature. Because of the excellent selectivity and repeatability in the detection of 1.0 and 2.0 ppm NH3 at room temperature achieved in this study, it is considered that the PANI/N-GQD/hollow In2O3 nanofiber composite sensor will be a favored gas-sensing material applied on human breath for the detection of hepatic or kidney disease.