Dye Sensitized Solar cell

... sensitizing complex, like the parent N719 polypyridyl−ruthenium complex, most widely used in high-performance DSC devices ... Raman measurements, implemented via the application of an external bias voltage, allow a comparative spectroscopic evaluation of the ...

Mesoporous films made of titanium dioxide nanowires are desirable for dye-sensitized solar cells because nanowires provide direct conduction pathways for photogenerated electrons. Anatase titanium dioxide nanowires with polycrystalline microstructure were synthesized on titanium foil using a three-step process. First, the top surface of the titanium foil was transformed to Na(2)Ti(2)O(4)(OH)(2) nanotubes through hydrothermal oxidation in NaOH. Next, the Na(2)Ti(2)O(4)(OH)(2) nanotubes were converted to H(2)Ti(2)O(4)(OH)(2) nanotubes by ion exchange. Finally, the H(2)Ti(2)O(4)(OH)(2) nanotubes were converted to polycrystalline anatase nanowires through a topotactic transformation. The film morphology evolution, crystal structure transformations and growth mechanism are described in detail. Titanium foil reacts with NaOH to form Na(2)Ti(2)O(4)(OH)(2) sheets, which exfoliate and spiral into nanotubes. The Na(2)Ti(2)O(4)(OH)(2) nanotubes are immersed in HCl solution to replace the Na(+) ions with H(+) ions. During the topotactic transformation of H(2)Ti(2)O(4)(OH)(2) nanotubes to anatase TiO(2) nanowires, the sheets made of edge bonded TiO(6) octahedra in the H(2)Ti(2)O(4)(OH)(2) nanotubes dehydrate and move towards each other to form anatase crystals oriented along the nanotube axis which creates a polycrystalline nanowire. These mesoporous TiO(2) nanowire films were suitable for use as dye-sensitized solar cell photoanodes.

We report the synthesis, electrochemical and photovoltaic properties of triphenylamine based novel organic sensitizer, comprising donor, electron-conducting and anchoring group. Different triphenylamines were synthesized as donor unit and connected to cyano-acidic acid acceptor over vinyl group. In this work, we studied on two novel dyes (TPA2, TPA3) by attaching methyl to m-position and diphenylamine to p-position of the basic triphenylamine

Zinc oxide (ZnO) nanorods decorated with gold (Au) nanoparticles have been synthesized and used to fabricate dye-sensitized solar cells (DSSC). The picosecond-resolved, time-correlated single-photon-count (TCSPC) spectroscopy technique was used to explore the charge-transfer mechanism in the ZnO/Au-nanocomposite DSSC. Due to the formation of the Schottky barrier at the ZnO/Au interface and the higher optical absorptions of the ZnO/Au photoelectrodes arising from the surface plasmon absorption of the Au nanoparticles, enhanced power-conversion efficiency (PCE) of 6.49% for small-area (0.1 cm2) ZnO/Au-nanocomposite DSSC was achieved compared to the 5.34% efficiency of the bare ZnO nanorod DSSC. The TCSPC studies revealed similar dynamics for the charge transfer from dye molecules to ZnO both in the presence and absence of Au nanoparticles. A slower fluorescence decay associated with the electron recombination process, observed in the presence of Au nanoparticles, confirmed the blocking of the electron transfer from ZnO back to the dye or electrolyte by the Schottky barrier formed at the ZnO/Au interface. For large area DSSC (1 cm2), ~130% enhancement in PCE (from 0.50% to 1.16%) was achieved after incorporation of the Au nanoparticles into the ZnO nanorods.

Dye sensitized solar cells (DSSC) on flexible substrates are ideal for making low-cost PV products available for a wide range of low power applications. In addition to lower material costs, a flexible solar cell also offers economies of scale through high volume roll-to-roll manufacturing. A disadvantage of using flexible polymer substrates, stems from their poor stability and degradation of both electrical and optical qualities when subjected to thermal processing steps required to make high efficiency TiO2 photoelectrodes. This study evaluates the potential of indium doped tin oxide (ITO) coated flexible glass, known as Corning® Willow® Glass, as an alternative to polymer substrates for fabricating flexible DSSCs. The strain point and bend radius of this glass allows it to withstand high sintering temperatures and also makes it potentially suitable for roll-to-roll manufacturing.

DSSCs fabricated using a 10 µm TiO2 mesoporous layer and sensitized with N719 dye demonstrate that flexible glass DSSCs show a power conversion efficiency of 4.53% compared to the 3.09% efficiency value obtained for DSSCs fabricated using commercially available ITO coated thick glass. The enhanced performance of the Willow Glass DSSC is reflected in the improved fill factors (FF). As expected, cells fabricated with similar procedures using fluorine doped tin oxide (FTO) coated glass substrates yielded a higher power conversion efficiency of 7.42% since its sheet resistance remains substantially lower even after the heat treatment unlike ITO. With FTO, instead of ITO, flexible glass DSSCs could potentially achieve higher efficiencies comparable to standard thicker glass DSSCs. This is expected when suppliers are able to produce FTO coated willow glass with reproducible electrical conductivity.

This study demonstrates for the first time that DSSCs can be fabricated using light weight, flexible glass substrates with comparable efficiencies to the standard thicker glass based DSSCs.