Facile Synthesis of Ultrathin 2D Tungsten Oxide Nanosheet as a Next-Generation Material for Enhanced Solar Conversion Efficiency
Mohammad Muaz, Farasha Sama, Tokeer Ahmad, M. Shahid, Absar Ahmad
Abstract
The global energy crisis and dependency on fossil fuels have compelled us to rely on renewable energy-based technology, a more sustainable, eco-friendly energy source. Dye-sensitized solar cells (DSSCs) are one such promising technology. Owing to its unique features, the two-dimensional (2D) tungsten oxide nanosheet is a top-notch photoactive material for DSSC applications. However, their extensive commercialization is limited by cost-efficient and environmentally benign synthesis of an ultrathin 2D nanosheets. In this work, an easily scalable and high-yield mechanochemical synthesis of ultrathin nanosheets has been proposed at ambient temperature. The phase evolution and formation mechanism of the WO 3 nanosheet has been investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) images. The as-synthesized WO 3 nanosheets were structurally characterized by multiple techniques like XRD, Fourier-transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), Raman, and ultraviolet–visible (UV–vis), while the nanoplate-like surface morphology was characterized by microscopic techniques like field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscope (HRTEM), and atomic force microscopy (AFM). The synthesized nanosheet was combined with a highly conductive graphene sheet (GS) in different doping percentages, and such modified hybrid systems were tested for DSSC application. Under the simulation of one-sun illumination, the DSSC using pristine photoelectrode material demonstrated a solar-power conversion efficiency of 9.31%, while the optimal doping of 0.6 wt % GS exhibited excellent performance with the highest power conversion efficiency of 10.47%, improved IPCE, and long term stability. A device prototype of the DSSC was developed utilizing the same, which continued to perform well for almost 3 months with a meagre loss in its performance. This work provides a promising approach for increasing the efficiency of solar cells by altering the WO 3 photoelectrode with GS, which acted as a next-generation material for commercializing DSSCs.