New LbL‐TiO₂/ZnO Compact Films to Improve Performance of Dye‐Sensitized Solar Cells

Abstract

The preparation of nanostructured thin films consisted of TiO 2 / ZnO bilayers (BL) and their application in dye-sensitized solar cells (DSCs) are reported. The film was prepared by the Layerby-Layer (LbL) technique using, respectively, acid and basic sols of TiO 2 and ZnO nanoparticles. The particles in the sols were characterized by dynamic light scattering (DLS) and the compact morphology of the LbL films were probed by scanning electronic (SEM) and atomic force (AFM) microscopies. The photoelectrochemical parameters of DSCs with 0, 15 and 20 BL were assessed by current-voltage (JxV) curves, incident photon-to-current efficiency (IPCE), electron lifetime and electrochemical impedance spectroscopy (EIS). These results revealed a significant improvement (up to 67%) on the DSC conversion efficiency promoted by LbL film underlayers, with enhancements ascribed to an efficient blocking effect preventing the FTO/I 3 À charge recombination and improved contact between the mesoporous-TiO 2 and the conducting substrate (FTO).

Supramolecular Approach in Energy Conversion Devices

“…This film revealed a significant improvement in the J SC and V OC , leading to a remarkable 67% improvement in the conversion efficiency of N3-sensitized DSCs. 242 The innovative ultrathin LbL all-nano-TiO 2 film as an interfacial layer created excellent adhesion of the TiO 2 layer on the FTO substrate 245 leading to an efficient electronic transport from TiO 2 to FTO and consequent impressive enhancement up to 62% in performances of N719-sensitized DSCs. 243 This nano-TiO 2 compact layer when employed in DSCs sensitized by mulberry, jaboticaba's skin, java plum and pomegranate fruit led to enhanced global efficiencies up to 66%.…”