Assembly&Properties Of Quasi-solid DSSC With Gel As Electrolyte&Conjugated Polymer As Counter Electrode

Dye-sensitized solar cell (DSSC) has attracted wide interest due to their high efficiency,low cost, environmental friendliness, simple assembly process and possible flexiblity.Conventional DSSC contains three parts of dye-sensitized photoanode, electrolyte andelectrodes. However, the liquid electrolyte has some disadvantages, such as volatility, fluidityand easy leakage. Traditional Pt counter electrode is relatively expensive and is not good forthe large scale production. In view of the above question, quasi-solid DSSC was assembledwith the gel electrolyte instead of liquid electrolyte and conjugated polymer electrode insteadof Pt electrode. The preparation process, structure and properties of gel electrolytes andconjugated polymer film electrode were systematically researched. Photoelectrictransformation performances of assembled DSSC were studied and the transmissionconditions of photo-induced charges in the interface of DSSC were analyzed. The mainresearch results are listed as follows:1) The gel electrolyte with high ionic conductivity was obtained with PVDF, NMP, I2/NaIand EC/PC as the gelling agent, solvent, redox and plasticizer, respectively. The best formulaof gel electrolyte is gained that NaI concentration is0.6mol/L, I2concentration is0.05mol/L,EC/PC mass ratio is2/1, mass content of PC/EC and PVDF in NMP is15wt%, respectively.Gel electrolyte membranes have abundant and large channels for electrolyte ion migration.Some hydrogen bonds between EC, PC and PVDF are beneficial for the freedom of I/I3migration. It also has the smaller Rct(charge transportation resistance) and higher conductivityof2.63mS/cm. Photoelectric conversion efficiency of DSSC assembled with gel electrolyteplasticized by PC/EC could reach to1.316%and was higher of50.74%than that of the gelelectrolyte without plasticizer.2) Rct of polyaniline (PANI), polyprrole (PPY) and polythiophene (PTh) prepared by theelectrochemical methods followed a gradual increase sequence. Wherein, PANI electrode has higher catalytic activity, lower surface resistance and better conductivity. PANI and PPYelectrode showed better reducibility. PANI electrode has the lowest body resistance of47.12Ωthat is closed to the Pt electrode. It is attributed to the microparous structure of PANI surface,which provides plenty of channels for the ion migration of electrolyte and guarantees for goodphotoelectric properties. Photovoltaic conversion efficiency of quasi-solid DSSC is about0.113%,0.046%and0.001%for PANI, PPy and PTh as the courter electrodes, respectively.The best preparation process of PANI electrode is monomer concentration of0.2mol/L,potential scan range of-0.2~0.85V, scan rate of10mV/s and scan circles of10. Under thiscondition, the photovoltaic conversion efficiency can be reached to0.113%. The bestpreparation process of PPY electrode is monomer concentration of0.1mol/L, scan voltage of0.8V and electrodeposition for15min and the assembed quasi-solid DSSC photovoltaicconversion efficiency is0.063%.3) Pt electrode prepared by the electrodeposition method has the more uniform surface andthe adaptable gap between particles which were more convenient for ion migration than thatobtained by the thermal decomposition method. The body resistance is42.47Ω, lower than Ptelectrode by thermal decomposition. Its Jscis6.63mA·cm2and η reaches to1.79%, whichwas all higher than Pt electrode prepared by thermal decomposition.4) Anatase TiO2nanopowders with regular microshape, particle size about20nm and lightabsorption occurred in the range of200~350nm were prepared successfully by sol-gel method.The volume ratio of raw materials is about1.00/3.30/0.30/0.26ofTetrabutyltitanate/Ethanol/Acetic acid/Distilled water and the calcination temperature wascontrolled at the range of450~550℃.