Dye-sensitized Solar Cell Fabricated by Electrostatic Layer-by-Layer Assembly of Amphoteric TiO₂ Nanoparticles

Abstract

Nanocrystalline TiO2 amphoteric colloidal charged particles and polyelectrolytes have been used to fabricate a dye-sensitized solar cell. Two weak polyelectrolytes, poly(allylamine hydrochloride) and poly(acrylic acid), and two strong polyelectrolytes, poly(dimethyldiallylammonium chloride) (PDAC) and poly(sodium 4-styrenesulfonate), have been utilized to assemble polyion/TiO2 nanocomposite multilayered films by the electrostatic layer-by-layer deposition technique. The layer-by-layer assembly of the TiO2 nanoparticles proceeds linearly as shown by sequential UV−vis absorption and thickness measurements. The morphology of these assemblies was characterized using atomic force microscopy. The nanoporous polyion/TiO2 films were sintered and used as working electrodes for cis-di(thiocyanato)-N,N-bis(2,2‘-bipyridyldicarboxylate)-ruthenium(II) (N3) sensitized solar cells. I−V characteristics of the solar cells made by the calcinated polyelectrolyte/TiO2 electrodes show several interesting results. (i) The short-circuit current does not linearly increase with the thickness of the TiO2 electrode, even though the adsorption behavior of the N3 dye shows a linear increase. (ii) The precursor polyelectrolytes used to assemble TiO2 play a major role in the photovoltaic performance of the solar cells. Thermogravimetric analysis studies show that the thermal stability of the polyelectrolytes may have a direct effect on the overall device efficiency. (iii) The photovoltaic performance of these solar cells is comparable to that of cells made by other methods such as spin casting, the layer-by-layer technique offers unsurpassed control in manipulating the final device thickness. An efficiency of 7.2% was obtained for the solar cell made from PDAC/TiO2 (200 bilayers) precursor film, under 1 sun at simulated Air Mass 1.5 direct irradiation.

Form and Function in Multilayer Assembly: New Applications at the Nanoscale

“…At this time, optimization of these systems to create higher efficiency second generation photovoltaic systems on flexible substrates is under study. A number of other studies have incorporated LBL thin films into either the electrode or the photoactive components of organic and organic-inorganic photovoltaics as well, [70,73,74] indicating the promise that layerby-layer technology has to offer in this area due to the ease with which different components can be juxtaposed. Photovoltaic and battery devices exhibit longer lifetimes in dry environments; however, fuel cells operate best at relatively high humidities.…”

Charge injection and trapping in TiO2 nanoparticles decorated silicon nanowires arrays

“…18 TiO 2 is one of the important oxide semiconductors and is proved to be suitable for photocatalytic, optical, and sensing applications. 19,20 Hybrid SiNWs and TiO 2 nanoparticles (NPs) have shown enhanced electrical and photodetection properties. 12 Other nanoparticles decorated nanostructures have also been investigated to improve electrical, dielectric, thermoelectric, and photodetection properties.…”

Preliminary Study of Performance of Dye-Sensitized Solar Cell of Nano-TiO<SUB>2</SUB> Coating Deposited by Vacuum Cold Spraying

“…4) High porosity is also beneficial for diffusion of reversible redox couples through TiO 2 membranes. 5) Several processing methods, including doctor blading, 2) spin coating, 6) screen printing 7,8) and layer by layer deposition, 9) have been employed to deposit nanocrystalline TiO 2 coatings applied to DSC. With all those processes, TiO 2 films are prepared from TiO 2 slurry or suspension in water with other additives such as detergent 9) and composite polyanion.…”

“…5) Several processing methods, including doctor blading, 2) spin coating, 6) screen printing 7,8) and layer by layer deposition, 9) have been employed to deposit nanocrystalline TiO 2 coatings applied to DSC. With all those processes, TiO 2 films are prepared from TiO 2 slurry or suspension in water with other additives such as detergent 9) and composite polyanion. 8) The film is formed through evaporation of water in the ambient atmosphere, which leads to the agglomeration TiO 2 particles in nanometer.…”