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The in situ photoelectropolymerization technique is used for synthesizing poly(3,4-ethylenedioxythiophene) (PEDOT) and the effect of different doping anions on overall solar cell performance is examined. The results have shown that a careful selection of the doping anions and the use of their lithium salts have improved the overall cell efficiency

The electron transport processes in Ti[O.sub.2] electrodes are analyzed by using stepped light induced transient measurements of photocurrent and voltage (SLIM-PCV). The effective filling of poly(3,4-ethylenedioxythiophene) (PEDOT) in the mesopores of dyed Ti[O.sub.2] layers is important in achieving the respectable conversion efficiency of PEDOT/dye-sensitized solar cells( DSCs) that is comparable with iodide/DSCs.

A high work function material such as titanium deposited by sputtering on fluoride-doped tin oxide (FTO) is investigated as an effective blocking layer for preventing electron leakage from FTO without affecting electron injection. The results have shown that thin films of titanium species (Ti[O.sub.x]) work as a compact blocking layer between FTO and Ti[O.sub.2] nanocrystalline film, improving [V.sub.oc] and the fill factor, finally giving better conversion efficiency for dye-sensitized Ti[O.sub.2] solar cells with ionic liquid electrolytes.

In order to explain the higher short-circuit current (Jsc) with comparable open-circuit voltage (Voc) from dye-sensitized solar cells (DSCs) based on gallium-modified ZnO (ZnO:Ga) porous electrodes, the diffusion coefficient (D) and electron lifetime (τ) in DSCs with and without Ga-modified ZnO were studied by stepped light-induced transient measurements of photocurrent and voltage. In comparison to DSCs based on ZnO electrodes, the ZnO:Ga-based solar cells provided lower D and higher τ values. The results were interpreted according to the transport-limited recombination model, where the Ga modification induced a higher density of intraband charge traps. At matched electron densities, a decrease in Voc from DSCs based on ZnO:Ga was observed, suggesting a positive shift of the ZnO:Ga conduction band edge. The higher Jsc can be explained by the positive shift of the ZnO:Ga conduction band edge in addition to the increased roughness factor of the electrode due to the Ga modification. [ABSTRACT FROM AUTHOR]

The higher short-circuit current ([J.sub.sc]) with comparable open-circuit voltage ([V.sub.oc]) from dye-sensitized solar cells (DSCs) based on gallium-modified ZnO (ZnO:Ga) porous electrodes is explained by studying diffusion coefficient (D) and electron lifetime in DSCs with and without Ga-modified ZnO by using stepped light-induced transient measurements of photocurrent and voltage. The higher [J.sub.sc] is explained with the help of positive shift of the ZnO:Ga conduction band edge in addition to the increased roughness factor of the electrode due to the Ga modification.

The charge transport properties of the unique ionic liquid crystal electrolyte (ILC) system ([C.sub.12]MImI/[I.sub.2]) are analyzed by investigating the exchange reaction-based diffusion coefficients. It is observed that model exhibited higher short-circuit current density and the higher light-to-electric conversion efficiency than the system utilizing the non-liquid crystalline ionic liquid because of the increased conductivity of ILC.

A series of panchromatic ruthenium sensitizers ( MJ sensitizers) with attached thiophene and phenyl units bearing alkyl chains was synthesized. A new synthetic route was used to examine all possible positions for the alkyl chains. The absorption spectra showed the sum of a ruthenium complex and peripheral organic chromophore units. The hypochromic effect and blueshift of the metal-to-ligand charge-transfer band observed in the modified ruthenium sensitizers were suppressed by changing the positions of the alkyl chains on the attached thiophene ring. Changing only one alkyl chain also influenced the performance of dye-sensitized solar cells. Ruthenium sensitizer MJ-10 with bulky substituent harvests visible and near-infrared light, and solar cells sensitized by MJ-10 exhibit an efficiency of 9.1 % under 1 sun irradiation. [ABSTRACT FROM AUTHOR]

A novel ruthenium-free organic dye, 3-(5-(4-(di-p-tolylamino)styryl)-2,3-dihydrothieno[3,4-b][1,4]dioxin-7-yl)-2-cyanoacrylic acid (coded as H01), is synthesized in a short sequence. The dye is composed of a di(p-tolyl)phenylamino moiety as an electron donor, a cyanoacrylate moiety as an electron acceptor, and an ethylenedioxythiophene unit as the spacer to bridge the donor and the acceptor. The as-prepared H01 dye is employed as a sensitizer in a dye-sensitized nanocrystalline TiO2solar cell, and the short-circuit photocurrent density (Jsc), open-circuit voltage (Voc), and fill factor (ff) of the device under AM 1.5 (100 mW cm−2) irradiation, are 15.22 mA cm−2, 0.67 V, and 0.72, respectively, corresponding to an overall conversion efficiency (Eff) of 7.33%. [ABSTRACT FROM AUTHOR]

Abstract: The preparation of a novel Nb2O5 blocking layer deposited between fluorine-doped tin oxide (FTO) and nanocrystalline TiO2 layer and its application for hydrophobic dye Z-907 sensitized ionic liquid-based solar cells have been studied. The Nb2O5 blocking layer prepared by spray pyrolysis method on FTO has been characterized by scanning electron microscope (SEM) equipped with energy dispersion X-ray analysis (EDX), transmit electron microscope (TEM), electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). Thin Nb2O5 films work as a potential blocking layer between FTO and nanocrystalline TiO2 layer in ionic liquid electrolyte cells, improving V oc and finally giving a better conversion efficiency of dye-sensitized TiO2 solar cells. Impedance spectroscopy indicates that the blocking layer can increase shunt resistance especially related with the charge transport at FTO–TiO2/dye/ionic liquid electrolyte and decrease the series resistance to some extent by constructing the potential barrier. Analysis of diffusion coefficient and lifetime of electrons in the cells confirms that they compensate each other when the blocking layer was introduced, leading to a little influence on the diffusion length (L). The remarkable improvements of V oc and fill factor for the DSCs suggest that the thin Nb2O5 is an effective blocking layer at FTO and TiO2 interface, contributing to unidirectional transport of electrons in the ionic liquid-based dye-sensitized nano-TiO2 solar cells. [Copyright &y& Elsevier]