Modification Of SnO₂-based Photoanode To Boost Photoelectric Properties For Dye-sensitized Solar Cells

Dye-sensitized solar cell (DSSC) based on semi-conductor nanocrystal hasbeen taken attention widely for low cost and high conversion efficiency. TiO2iscommonly used as photoanode of DSSCs. SnO2with larger band gap and fasterelectron mobility is a promising photoanode material. But the performance ofSnO2-based DSSCs is much less than TiO2-based DSSCs. Thus, in this workefforts have been made to improve photoelectric performance of SnO2-basedDSSCs.Three-dimensional flower-like SnO2crystal has been fabricated bysolvothermal method through controlling the reaction condition. And crystalgrowth process was followed with the change of hydrothermal time. The crystalstructure and microscopic morphology have been characterized with X-raydiffraction (XRD), scanning electron microscope (SEM), transmission electronmicroscope (TEM) and infrared radiation (IR). According to the results, theflower-like SnO2architecture consists of independent SnO2nanorods whichgrow respectively along c-axes direction with enclosed (110) lattice faces. Thegrowth of flower-like SnO2crystal is a dynamics process with internal structurecharacteristics based on thermodynamics.Colloid solution of SnO2with various morphologies has been prepared bytraditional fabrication method for photoanode colloid. Thin film of SnO2photoanode was coated on FTO conductive glass through blade coatingtechnology, and treated using various concentrations of TiCl4solutions. Themorphology and light absorption of prepared SnO2photoanodes were tested andcharacterized with SEM and Ultraviolet-visible spectroscopy (UV-Vis), andphotoelectric performance (J-V curves) and charge transfer behavior (Electrochemical Impedance Spectroscopy, EIS) for assembled DSSCs.According to the results, DSSC with flower-like SnO2as the photoanode exhibitsbetter photovoltaic performance than SnO2particle. Photoelectric conversionefficiency of0.65%reaches and acquires increase of38%. And conversionefficiency of SnO2-TiO2-DSSC fabricated through TiCl4solution increases fourtimes than which of pure SnO2-DSSC. Energy efficiency reaches the maximum,3.24%, when TiCl4concentration is0.15M, and charge transfer behavior isoptimal. Thus, changing the microscopic morphology of SnO2and the treatmentof TiCl4solution are advantaged to improve the photoelectric performance ofSnO2-based DSSCs.