Flexible Nano-TiO(2) Sheets Exhibiting Excellent Photocatalytic and Photovoltaic Properties by Controlled Silane Functionalization—Exploring the New Prospects of Wastewater Treatment and Flexible DSSCs

[Image: see text] TiO(2) nanoparticles surface-modified with silane moieties, which can be directly coated on a flexible substrate without the requirement of any binder materials and postsintering processes, are synthesized and characterized using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, Brunauer–Emmett–Teller, X-ray photoelectron spectroscopy, Raman spectroscopy, photoluminescence spectroscopy, time-correlated single-photon counting, and transmission electron microscopy. The viability of the prepared surface-modified TiO(2) (M-TiO(2)) sheets as a catalyst for the photo-induced degradation of a model dye, methylene blue, was checked using UV–visible absorption spectroscopy. The data suggest that, compared to unmodified TiO(2), M-TiO(2) sheets facilitate better dye-degradation, which leads to a remarkable photocatalytic activity that results in more than 95% degradation of the dye in the first 10 min and more than 99% of the degradation in the first 50 min of the photocatalytic experiments. We also demonstrate that M-TiO(2) can be recycled with negligible reduction in photocatalytic activity. Further, the photovoltaic properties of the developed M-TiO(2) sheets were assessed using UV–visible absorption spectroscopy, electrochemical impedance spectroscopy (EIS), and photochronoamperometry. Dye-sensitized solar cells (DSSC) fabricated using M-TiO(2) as the photoanode exhibited a photoconversion efficiency of 4.1% under direct sunlight. These experiments suggested that M-TiO(2) sheets show enhanced photovoltaic properties compared to unmodified TiO(2) sheets, and that, when N-719 dye is incorporated, the dye–TiO(2) interaction is more favorable for M-TiO(2) than bare TiO(2). The simple solution processing method demonstrated in this paper rendered a highly flexible photoanode made of M-TiO(2) with superior charge-separation efficiency to an electrode made of bare TiO(2). We propose that our findings on the photovoltaic properties of M-TiO(2) open up arenas of further improvement and a wide scope for the large-scale production of flexible DSSCs on plastic substrates at room temperature in a cost-effective way.