Flexible Nano-TiO2 Sheets Exhibiting Excellent Photocatalytic and Photovoltaic Properties by Controlled Silane Functionalization-Exploring the New Prospects of Wastewater Treatment and Flexible DSSCs.

TiO2 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 TiO2 (M-TiO2) 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 TiO2, M-TiO2 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-TiO2 can be recycled with negligible reduction in photocatalytic activity. Further, the photovoltaic properties of the developed M-TiO2 sheets were assessed using UV-visible absorption spectroscopy, electrochemical impedance spectroscopy (EIS), and photochronoamperometry. Dye-sensitized solar cells (DSSC) fabricated using M-TiO2 as the photoanode exhibited a photoconversion efficiency of 4.1% under direct sunlight. These experiments suggested that M-TiO2 sheets show enhanced photovoltaic properties compared to unmodified TiO2 sheets, and that, when N-719 dye is incorporated, the dye-TiO2 interaction is more favorable for M-TiO2 than bare TiO2. The simple solution processing method demonstrated in this paper rendered a highly flexible photoanode made of M-TiO2 with superior charge-separation efficiency to an electrode made of bare TiO2. We propose that our findings on the photovoltaic properties of M-TiO2 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.

Low cost, high efficiency flexible supercapacitor electrodes made from areca nut husk nanocellulose and silver nanoparticle embedded polyaniline.

Energy storage is a key aspect in the smooth functioning of the numerous gadgets that aid easy maneuvering through modern life. Supercapacitors that store energy faradaically have recently emerged as potential inventions for which mechanical flexibility is an absolute requirement for their future applications. Flexible supercapacitors based on nanocellulose extracted from easily available waste materials via low cost methods have recently garnered great attention. In the present work, we discuss the construction of flexible, binder-free supercapacitive electrodes using nanocellulose extracted from locally available areca nut husks and polyaniline embedded with silver nanoparticles. The prepared electrodes were characterized using SEM, TEM, XRD, FTIR, EDX and electrochemical characterization techniques such as CV, galvanostatic charge-discharge, chronoamperometry and EIS. A specific capacitance of 780 F g-1 was obtained for the silver nanoparticle embedded polyaniline-nanocellulose (Ag-PANI-NC) substrate supported electrodes, which is ∼4.2 times greater than that of bare polyaniline-nanocellulose electrodes. We attributed this enhancement to a lowering of the activation energy barrier of correlated electron hopping among localized defect states in the composite matrix by the Ag nanoparticles. An energy density value of 15.64 W h kg-1 and a power density of 244.8 W kg-1 were obtained for the prepared electrodes. It was observed that the Ag-PANI-NC based electrode can retain ∼98% of its specific capacitance upon recovery from mechanical bending to extreme degrees.

Scope of surface-modified molecular and nanomaterials in gel/liquid forms for developing mechanically flexible DSSCs/QDSSCs.

The advanced lifestyle of the human race involves heavy usage of various gadgets which require copious supplies of energy for uninterrupted functioning. Due to the ongoing depletion of fossil fuels and the accelerating demand for other energy resources, renewable energy sources, especially solar cells, are being extensively explored as viable alternatives. Flexible solar cells have recently emerged as an advanced member of the photovoltaic family; the flexibility and pliability of these photovoltaic materials are advantageous from a practical point of view. Conventional flexible solar cell materials, when dispersed in solvents, are usually volatile and create severe stability issues when incorporated in devices. Recently, non-volatile, less viscous functional molecular liquids/gels have been proposed as potential materials for use in foldable device applications. This perspective article discusses the scope of surface-modified non-volatile molecular and nanomaterials in liquid/gel forms in the manufacturing and deployment of flexible photovoltaics.

Synthesis and electrochemical characterization of electroactive IoNanofluids with high dielectric constants from hydrated ferrous sulphate.

An iron oxide based-electroactive IoNanofluid with a high dielectric constant, high stability and low viscosity was synthesized from ferrous sulphate heptahydrate via a facile microwave assisted one-step route in 1-butyl-4-methylpyridinium chloride. The IoNanofluid exhibited CE coupled faradaic redox reactions involving reversible chemical reaction and reversible electron transfer steps. A transition from diffusion controlled to surface controlled capacitive processes was observed at varying scan rates. The efficiency of the charge-discharge process was greater than 94% even after 100 cycles.