Layer In Dye-sensitized Solar Cells Research Articles

Microwave processing of TiO2 blocking layers for dye-sensitized solar cells

The microwave heat treatment of blocking layers for dye-sensitized solar cells has been investigated. It has been found that the solar cell efficiencies achieved with microwave heating were considerably higher than those achieved with conventional heating at low temperatures (100°C). This was attributed to microwave heating providing better sintering of the blocking layer and better interfacial contact between the substrate and the TiO2 layers. These results are promising with regard to the application of microwave heating to the production of dye-sensitized solar cells on flexible polymer substrates.

Improved Voltage and Fill Factor by Using Zinc Oxide Thin Filmas a Barrier Layer in Dye-Sensitized Solar Cells

A series of dye-sensitized solar cells based on ZnO-modifiedTiO2 nano-porous films have been prepared. The current–voltagecharacteristics of the cells show that the ZnO-modification can improvethe open-circuit voltage and the fill factor but can decrease theshort-circuit current. Dark current and transient photovoltagemeasurements are used to study the back reaction. It is indicated thatthe recombination process is suppressed by blocking the holetransporting from the nano-porous TiO2 since the surface of thesemiconductor is almost fully covered with ZnO as a barrier layer.

TiO2 sol–gel blocking layers for dye-sensitized solar cells

Abstract The application of a thin, compact layer of TiO 2 on the conductive glass substrate in a dye-sensitized solar cell can prevent short-circuits in the solar cell and, therefore, prevent the back transfer of electrons by blocking direct contact between the electrolyte and the conductive substrate. In this work, it has been found that compact films of TiO 2 , produced by a sol–gel method and applied by dip-coating, increased the short-circuit current and efficiency of the solar cells. As the number of TiO 2 coatings increased, the solar cell efficiency increased, due to the film becoming thicker and more smooth and uniform. To cite this article: J.N. Hart et al., C. R. Chimie 9 (2006) .

Low-temperature Fabrication of Nano-porous TiO2 Layers for Dye-sensitized Solar Cells. Fabrication of Ion-diffusion Paths

Abstract In dye-sensitized solar cells, it is required to build up both of ion paths and electron paths in TiO2 layers for low-temperature fabrication process. In this report, ion paths are focused on. Semiconductive layers are composed of TiO2 nanocrystals (P25) and needle-shape TiO2 crystals (FTL 100). By adding 20% of the needles into P25, photocurrent increased from 5.3 to 7.7 mA/cm2. Pore distributions, surface areas, Cole–Cole plot and currents passing through TiO2 layers were measured. These results suggest that the increase in the photocurrent is associated with the formation of ion paths in TiO2 layers.

Ionic liquid crystal as a hole transport layer of dye-sensitized solar cells

Use of a new ionic liquid crystal, 1-dodecyl-3-methylimidazolium iodide, and iodine as an electrolyte of dye-sensitized solar cells leads to a high short circuit photocurrent density and a high light-to-electricity conversion efficiency, due to a self-assembled structure of the imidazolium cations, resulting in high conductivity of the electrolyte.

Effect of Semiconductor and Dye Interfacial Properties in Dye-Sensitized Solar Cells

ABSTRACTThe back recombination processes of electrons from the semiconductor to the oxidized dye and the oxidized redox species can dramatically reduce the efficiency of conventional dyesensitized solar cells (DSSCs). In this work, we have used the electrostatic layer-by-layer (ELBL) assembly technique to specifically manipulate and control the interface between the semiconductor and adsorbed dye layers in DSSCs to potentially minimize this recombination behavior. The interfacial modification has been achieved by applying different combinations and thicknesses of polyelectrolytes using the ELBL method and the performance of the cells has been monitored by measuring the I-V characteristics and the efficiency of the solar cells. The results indicate that an ultrathin polyelectrolyte film, on the order of a few Angstroms, between the semiconductor and the dye layer plays a crucial role on the performance of the solar cell. More specifically, the efficiencies of the DSSCs do not show any improvement after the interfacial treatment when compared to untreated samples. Surprisingly, the efficiency of the cells decreases to some degree, depending on the thickness of the polyelectrolyte films. This suggests that incorporation of a thin (several Angstroms) passive layer between the semiconductor and dye layer in these devices results in an increased resistance of the device and do not significantly reduce the back electron recombination as was originally anticipated. These results show interesting mechanistic information regarding the interfacial interactions of semiconductor/dye interfaces in DSSCs.