Structural and Optical Analysis of Ag Nanoparticles assisted Vertically Aligned TiO2 Nanowires based photoanode for Dye-sensitized Solar Cells Application

Abstract

In this work, vertically aligned TiO 2 -Nanowires (TiO 2 -NWs) and Ag Nanoparticles assisted TiO 2 Nanowires (TAT-NWs) were deposited on glass and flexible PET substrates using the Glancing Angle Deposition (GLAD) technique. The morphology and structural analysis of the samples manifest the successful deposition of vertically aligned TiO 2 -NWs and TAT-NWs. The HR-TEM image of TiO 2 -NWs shows the polycrystalline nature. Further, the XRD result confirms the polycrystalline nature of both the TiO 2 -NWs and TAT-NWs samples. Besides, the HR-TEM image confirms the presence of small crystal grains of Ag Nanoparticles (Ag-NPs) at the mid of the annealed TAT-NWs. It is evident from the Selective Area Electron Diffraction (SAED) analysis of the TiO 2 -NWs and annealed TAT-NWs that the crystallinity of TiO 2 present in the annealed TAT-NWs improves after annealing. The absorption spectrum analysis of TAT-NWs deposited on glass substrate shows enhance absorption peak in the visible region with a maximum peak at ~463 nm wavelength compare to the TiO 2 -NWs, which may be attributed to the Surface Plasmon Resonance (SPR) effect of Ag-NPs. Further, it is interesting to observe that the TAT-NWs deposited on PET substrate show further absorption enhancement in the UV and visible region. In addition, the Photoluminescence analysis reveals that the bandgap of the TiO 2 -NWs is ~3.12 eV, which supports the bandgap extracted from the Tauc plot. Therefore, the proposed method of fabricating TAT-NWs on glass and flexible ITO coated PET substrate using the GLAD technique may be applicable for developing novel photoanode for Dye-sensitized Solar Cells (DSSCs) and other optoelectronic applications.