Glancing angle deposited titania films for dye-sensitized solar cells

A series of sculptured porous nano-columnar titanium oxide films were prepared by glancing angle deposition (GLAD) method using an electron-beam evaporation system. The films were deposited on ITO glasses at various incident angles from 53° to 86°and used as photoanode in a dye-sensitized solar cell (DSSC). The as-deposited TiO2 films are comprised of helical nano-columns and assembled in an orderly manner with gaps or pores in between. The porous nanostructured films provide a synergetic effect of high surface area, effective route for electron transfer, tight interfaces, and enhanced light trapping, which are all beneficial for higher cell efficiency. The DSSCs incorporated with the GLAD films of 4 μm thick exhibited a high fill factor (FF) up to 0.77. The TiO2 film deposited at an incident angle of 73° provides the largest internal surface area and the largest amount of dye absorption and results in the highest light conversion efficiency of 2.78%.