Dye-sensitized solar cells (DSSCs) belong to the group of thin-film solar cells which have been under extensive research for more than two decades due to their low cost, simple preparation methodology, low toxicity and ease of production. Still, there is lot of scope for the replacement of current DSSC materials due to their high cost, less abundance, and long-term stability. The efficiency of existing DSSCs reaches up to 12%, using Ru(II) dyes by optimizing material and structural properties which is still less than the efficiency offered by first- and second-generation solar cells, i.e., other thin-film solar cells and Si-based solar cells which offer ~ 20–30% efficiency. This article provides an in-depth review on DSSC construction, operating principle, key problems (low efficiency, low scalability, and low stability), prospective efficient materials, and finally a brief insight to commercialization.

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Dye-Sensitized Solar Cells: Fundamentals and Current Status

Hydrogen production from water splitting by photo/photoelectron-catalytic process is a promising route to solve both fossil fuel depletion and environmental pollution at the same time. Titanium dioxide (TiO2) nanotubes have attracted much interest due to their large specific surface area and highly ordered structure, which has led to promising potential applications in photocatalytic degradation, photoreduction of CO2, water splitting, supercapacitors, dye-sensitized solar cells, lithium-ion batteries and biomedical devices. Nanotubes can be fabricated via facile hydrothermal method, solvothermal method, template technique and electrochemical anodic oxidation. In this report, we provide a comprehensive review on recent progress of the synthesis and modification of TiO2 nanotubes to be used for photo/photoelectro-catalytic water splitting. The future development of TiO2 nanotubes is also discussed.

One‐dimensional TiO2 Nanotube Photocatalysts for Solar Water Splitting

Dye-Sensitized Solar Cells

Review on polymer electrolyte in dye-sensitized solar cells (DSSCs)

Dye sensitized solar cells are attractive as simple and low cost renewable energy source. In dye sensitized solar cells, photo-anode plays significant role for collection and transportation of photo-excited electrons from dye to external electric circuit. Usually, wide band gap semiconducting metal oxides like titania, zinc oxide etc are deposited over transparent conducting substrate to prepare the photo-anodes. The performances of the photo-anodes depend on the band gap, morphology, composition of metal oxides and thickness of metal oxide layers. Enormous research efforts have been accomplished for studying the photo-voltaic characteristics of the dye sensitized solar cells by varying the aforementioned influencing parameters. However, the research activities executed towards the modification of photo-anode for dye sensitized solar cell application are quite scattered. It seems therefore important to summarize the research efforts executed towards the development of photo-anode for dye sensitized solar cell. In the present review, the effect of influencing parameters on the photo-voltaic characteristics of photo-anode for dye sensitized solar cell application is discussed. The descriptions have been made by summarizing the relevant literature reports.

Effects of doping, morphology and film-thickness of photo-anode materials for dye sensitized solar cell application – A review

Mechanism of titania nanograss formation during anodization

In TiO2 nanoparticle based dye sensitized solar cells (DSSC), the electron injected from the dye has to cross multiple interparticle boundaries in random directions before reaching the electrode. For application in DSSCs, the directional pathway for electron transport through the nanotubes is known to reduce the recombination rate. In the present study, titania nanotubes with nanograss layer have been fabricated by anodization of titanium foil in fluoride containing organic electrolyte. Dye sensitized solar cells with photoanode made of titania nanotubes covered with nanograsswas found to have a higher efficiency than ones made with only titania nanotubes of the same length.This can be attributed to enhanced dye adsorption on nanotubes with nanograss. The efficiency of DSSC using titania nanotubes is also affected by the annealing conditions such as duration, temperature.

Effect of Nanograss and Annealing Temperature on TiO2 Nanotubes Based Dye Sensitized Solar Cells

Though researchers worldwide have attempted to fabricate faceted titania nanoparticles with a higher fraction of {001} facets, which have high surface energy, the approaches have focused on use of either a very aggressive heating schedule or highly corrosive chemicals like HF. The current article reports a simple method for the transformation of the titania nanotubes to faceted nanoparticles (size varying from 15–120 nm) at relatively low temperatures and heating rates, without the use of any other corrosive chemicals, utilizing only the electrolyte inside the titania nanotubes remnant from the anodization of the titanium substrate. The formation of faceted nanoparticles was found to be strongly dependent on fluorine concentration and on initial state of titania nanotubes (amorphous/crystalline) and annealing temperature. The formation of the unique “nanorod in nanoporous” structures has been reported for the first time. The current article deals with a detailed study of the formation of these unique nano...

Mechanism of Formation of Faceted Titania Nanoparticles from Anodized Titania Nanotubes

Simple electrochemical synthesis of black metal oxides for enhanced visible light absorption

Antimony doped and undoped nanostructured thin films of AgIn1 − xGaxSe2 and Ag(InGa)5Se8 on optically flat soda lime glass substrates are prepared by a three stage co-evaporation process. Energy dispersive analysis of X-rays (EDAX) and X-ray photoelectron spectroscopy in conjunction with atomic force microscopic technique and scanning electron microscopic technique are used, respectively, for compositional and surface morphological analysis of the films. X-ray diffraction (XRD) data on the films are analysed to estimate the influence of antimony doping and indium replacement by gallium, on the structure of the films, by determining the anion–cation bond lengths and anion displacement in the thin films. The obvious dependence of band gap on the composition of the films establishes the possibility of band gap tailoring of the films. Low temperature optical absorbance measurements in the temperature regime 90–301 K are used for investigating the effect of doping on the temperature coefficient of band gaps of the films. Rutherford scattering spectra quantify the thickness of the films for conductivity (σ) measurements. The films exhibit n-type conductivity with two linear regions in the ln(σ) versus temperature inverse graphs, which indicate a defect activated conduction and intrinsic conduction, respectively, in the near room temperature and high temperature regions.

Johns Naduvath

Papers

Mechanism of titania nanograss formation during anodization

Effect of Nanograss and Annealing Temperature on TiO2 Nanotubes Based Dye Sensitized Solar Cells

Mechanism of Formation of Faceted Titania Nanoparticles from Anodized Titania Nanotubes

Simple electrochemical synthesis of black metal oxides for enhanced visible light absorption

Structural, optical and electrical properties of Sb doped and undoped AgIn1 − xGaxSe2 and Ag(InGa)5Se8 thin films