Effect of polyaniline (PANI) on efficiency enhancement of dye-sensitized solar cells fabricated with poly(ethylene oxide)-based gel polymer electrolytes

Journal of Solid State Electrochemistry - Ionically conducting gel polymer electrolytes can be used effectively to improve the problems associated with liquid electrolytes in dye-sensitized solar...     

Efficient passivation of SnO2 nano crystallites by Indoline D-149 via dual chelation

For the first time in SnO₂ based dye solar cells, here we report, efficiency exceeding 3% of the cells consisting with Indoline D-149 dye with unmodified SnO₂ nano-crystallites. The cells sensitized with metal free D-149 dye together with liquid electrolyte comprising with 0.5 M tetrapropyl ammonium iodide and 0.05 M iodine in a mixture of acetonitrile and ethylene carbonate (1:4 by volume) delivered a short circuit current density of 10.4 mA cm^?2 with an open circuit voltage of 530 mV under the illumination of 100 mW cm^?2 (AM1.5) having an efficiency of 3.1%. As evident from the FTIR measurement, strong surface passivation of recombination centers of SnO₂ crystallites due to the dual mode of attachment of dye molecules to the surface of SnO₂ via both COOH and S–O direct bond might be the possible reason for this enhancement in these SnO₂ based cells.     

Highly efficient,PbS:Hg quantum dot–sensitized,plasmonic solar cells with TiO2 triple-layer photoanode

Journal of Solid State Electrochemistry - Highly efficient, PbS:Hg quantum dot–sensitized, plasmonic solar cells with TiO2 triple-layer photoanode were fabricated by successive ionic layer...     

Mixed cation effect and iodide ion conductivity in electrolytes for dye sensitized solar cells

Dye-sensitized solar cells (DSSCs) offer an alternative to conventional silicon solar cell because of low cost and easy fabrication. However, one major drawback in DSSCs is their low efficiency. This paper reports the effect of using a binary iodide salt mixture with different size cations on the efficiency enhancement in dye sensitized solar cells based on polymer gel electrolytes. Several different polymers, such as polyacrylonitrile (PAN), polymethylmethacrylate (PMMA), poly (vinylidenefluoride (PVdF)), and polyethylene oxide (PEO) have been used as host polymers. A binary iodide mixture consisting of an alkaline iodide salt (small cation) and a quaternary ammonium iodide salt such as tetrapropyl ammonium iodide (Pr₄NI) (large cation) has been used as the iodide ion source. In some of these systems, efficiency enhancement of more than 25% has been reached due to the “mixed cation effect”. From these studies, it was established that the variation of the power conversion efficiency with the concentration ratio of the two iodide salts follows the same trend as the short circuit current density (J _sc) and goes through a maximum at a particular salt concentration ratio. The maximum efficiency was found to be higher than the efficiencies of the DSSCs with only a single iodide salt in the electrolyte. The J _sc in these DSSCs appears to be governed by the iodide ion conductivity of the gel electrolyte. The observed efficiency enhancement has been explained on the basis of the electrode effects as well as electrolyte effects where the cations play a dominant role.

     

A novel tricyclic polyketide and its biosynthetic precursor azaphilone derivatives from the endophytic fungus Dothideomycete sp

Azaphilone derivatives 1 and 2 and a novel tricyclic polyketide 3, together with a known azaphilone, austdiol (4), were isolated from the endophytic fungus Dothideomycete sp., which was isolated from a Thai medicinal plant, Tiliacora triandra. Compound 3 is the first polyketide having a tricyclic 6,6,6 ring system, which is similar to that of a terpenoid skeleton. The absolute configurations of stereogenic centers in 1-3 were addressed by Mosher's method and biosynthetic analogy with a known azaphilone isolated from the same fungus. Cytotoxic and antimicrobial activities of the isolated compounds were evaluated.     

Sensitization of aluminum chloride adsorbed tin(IV) oxide nanocrystalline films with Rose Bengal

The anionic dye Rose Bengal was found to surface chelate more strongly to SnO2 nanocrystalline films previously kept immersed in a solution of washed and dried AlCl3. Dye-sensitized photoelectrochemical cells made from such films exhibit enhanced quantum and energy conversion efficiencies. The result is explained as caused by binding of AlCl3 to SnO2 surface by elimination of Cl atoms and stronger bonding of Rose Bengal to Al, enhancing dye adsorption and suppression of back electron transfer by bridging of an Al atom between Sn and the dye molecule.     

Efficiency enhancement in dye-sensitized solar cells using hierarchical TiO2 submicron size spheres as a light scattering layer

Journal of Solid State Electrochemistry - The photoanode of a dye-sensitized solar cell (DSSC), usually made with a nanoporous TiO2 semiconductor layer sensitized with N719 dye, plays a crucial...     

Volatile solvent-free solid-state polymer-sensitized TiO2 solar cells with poly(3,4-ethylenedioxythiophene) as a hole-transporting medium

Novel, volatile solvent free, solid-state solar cells were fabricated with mesoporous TiO2 electrodes sensitized using thiophene derivatives containing carboxyl groups and in situ electropolymerized poly(3,4-ethylenedioxythiophene) as a hole-transporting material together with the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide and lithium bis(trifluoromethanesulfone)imide as additives for charge transport promotion.     

Dependence of photovoltaic parameters on the size of cations adsorbed by TiO2 photoanode in dye-sensitized solar cells

The effects of “pre-adsorbed cations” in photoanodes on the performances of dye-sensitized solar cells (DSSCs) were studied using two different size cations (K⁺ and guanidine cation (G⁺)). While the DSSCs with optimized K⁺ ions pre-adsorbed photoanodes showed a maximum efficiency of 7.04%, the DSSCs with G⁺ ions pre-adsorbed photoanodes showed an efficiency of 6.73%. DSSCs fabricated with conventional photanodes (without pre-cation adsorption) showed an efficiency of 6.21%. Differences in efficiencies are very likely due to the cation pre-adsorption effects and could be due to a higher number of K⁺ cation adsorption per unit area of TiO₂ surface of the photoanode compared to a smaller number of G⁺ cation adsorption in TiO₂, due to their difference in sizes. This pre-cation adsorption technique can be used to improve the overall efficiency of a DSSC by about 14% fold over the conventional photoanodes use in DSSCs, specially using smaller cations.