Enhanced Open‐Circuit Photopotential in Quasi‐Solid‐State Dye‐Sensitized Solar Cells Based on Polymer Redox Electrolytes Filled with Anodic Titania Nanotubes

Abstract

Dye-sensitized solar cells (DSCs), are already in the top ten photovoltaic devices attaining the largest overall power-conversion effi ciencies ( > 10% under 1 sun AM1.5G illumination [ 1 ] ), due mainly to their potentially low-cost fabrication, the possibility of transparency and color selectivity, effi cient light absorption by all incident angles and their ability to be integrated into building and automobile applications. [ 2 ] To make the next step towards full commercialization and compete on equal terms with silicon and thin fi lm solar cells, DSCs have to demonstrate enhanced long term stability under thermal and light stress conditions. The most effi cient DSCs utilize a liquid electrolyte consisted of the I − /I 3 − redox couple, dissolved in an organic solvent (e.g., acetonitrile); this kind of volatile solvent (resulting in partial liquid leakage and/or evaporation) is recognized to be the main limiting factor shortening the lifetime of the devices. [ 3 ] To overcome these problems, two alternatives have been proposed: i) the use of solvent-free ionic-liquid-based electrolytes, [ 4 , 5 ] and ii) the application of solidifi ed electrolytes based on organic [6][7][8][9] and inorganic [ 10 ] polymers, nanoparticles, [ 11 , 12 ] and liquid crystals, [ 13 ] attaining maximum effi ciencies on the order of 7-8%. [ 14 ] Following this direction, hybrid composite polymer electrolytes have been prepared by our group in the past: a linear polymer with high viscosity (polyethylene oxide) was used in order to solidify the common liquid electrolytes and a fi ller consisted of a powder of titania nanoparticles was further embodied in the polymer electrolytes to enhance amorphicity. [ 15 ] The obtained photovoltaic effi ciencies (2.5-4.5%) of the DSCs incorporating such solidifi ed polymer electrolytes were (at the time) among the best reported in literature. [16][17][18] These efforts to incorporate metal oxide nanoparticles between the polymer chains has since motivated a lot of research groups to use similar semiconducting nanostructures (TiO 2 , SiO 2 , carbon nanotubes, graphite etc.) to fi ll various polymer electrolytes. [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] Among others, special mention should be made on recently prepared advanced composite polymer (polyethylene glycol and nafi on) electrolytes using hydrothermally prepared titania nanotubes (NTs) as fi llers. [ 34 , 35 ] In this work, taking advantage of the strong experience in the electrochemical preparation of ordered metal oxide nanostructures, [36][37][38] we have prepared novel nanocomposite polymer electrolytes based on potentiostatically grown nanotubular titania fi llers incorporated into polyethylene oxide matrices. The polymeric electrolyte without a fi ller (used as a reference) presented an overall power conversion effi ciency ( η ) of 4.4%, when incorporated in a DSC. When this electrolyte was fi lled with the nanotubular anodic powder, the effi ciency was increased by more than 18% (reaching values up to 5.4%), mai...

Fabrication of Stable Dye Sensitized Solar Cell with Gel electrolytes Using Poly(ethylene oxide)-Poly(ethylene glycol)

“…The overall conversion efficiency of 4.2% was reported for the PEO based gel electrolyte with TiO2 nanoparticles [26] and for anodized TiO2 nanotubes filled PEO the efficiency of 5.4% was achieved [27].Supramolecular ionic liquid gel based DSSC has been reported for its long term stability with a PCE of 4.79% [28].Yanto Shi et al had reported that PEO based gel electrolyte have showed the PCE of 6.4% using ZnO based photoanodes [29].Polyaniline (PANi) filled PEO electrolytes have showed better catalytic activity towards the triiodide reduction and a PCE of 6.1% was demonstrated [30]. Numerous attempts have been made to fabricate PEO based gel electrolytes and its application in DSSC such as using various alkali iodide salts, filler particles, aqueous solvents [31].…”

Solid state metal-free eosin-Y dye sensitized solar cell based on PVdF-HFP electrolytes: combined effect of surface modified TiO2 and plasticizer on electrochemical and photovoltaic properties

“…have been used as fillers in electrolytes for dye-sensitized solar cell applications [27][28][29][30][31][32][33][34][35][36][37][38]. Among them, TiO 2 nanoparticles are considered as one of the most promising fillers because of their availability in nature, UV resistance, photocatalytic activity for pollutant removal, photoelectrochemical conversion, and anti-bacterium properties and polymorph crystalline structures like anatase, brookite, and rutile [39,40].…”

Dye molecules in electrolytes: new approach for suppression of dye-desorption in dye-sensitized solar cells

“…One of the reason for poor long-term stability of DSSCs is weakly bound dye molecules on TiO 2 surface12. Recently, the long-term stability of DSSCs has been improved through molecular engineering of a sensitizer in conjunction with the use of a nonvolatile electrolyte13141516. However, the cell efficiencies of the DSSCs were lower than those of conventional DSSCs, and the material is too expansive because of the use of ionic liquid.…”