Structural and Optical Properties of Nanocrystalline TiO2 with Multiwalled Carbon Nanotubes and Its Photovoltaic Studies Using Ru(II) Sensitizers

In this study, the in situ sol-gel method has been deployed to prepare the titanium dioxide/multiwalled carbon nanotubes (TiO 2 /MWCNTs) nanocomposite (NCs) powders with varying content of MWCNTs (0.01-1.0 wt %), to construct the dye-sensitized solar cells (DSSCs). First, binder-free NCs were deposited on a transparent-conducting F:SnO 2 (FTO) glass substrate by a doctor-blade technique and then anchored with Ru(II)-based dyes to either N719 or ruthenium phthalocyanine (RuPc). The structural and optical properties and interconnectivity of the materials within the composite are investigated thoroughly by various spectral techniques (XRD, XPS, Raman, FT-IR, and UV-vis), electron microscopy (HRTEM), and BET analysis. The experimental results suggest that the ratio of MWCNTs and TiO 2 in NCs, morphology, and their interconnectivity influenced their structural, optical, and photovoltaic properties significantly. Finally, the photovoltaic performances of the assembled DSSCs with different content of MWCNTs to TiO 2 films anchored with two different dyes were tested under one sun irradiation (100 mW/cm 2 ). The measured current-voltage ( IV ) curve and incident photon-to-current conversion efficiency (IPCE) spectra of TiO 2 /0.1 wt % MWCNTs (T@0.1 C) for N719 dye show three times more power conversion efficiency (η = 6.21%) which is opposed to an efficiency (η = 2.07%) of T@0.1 C for RuPc dye under the same operating conditions.