Enhanced performance of dye-sensitized solar cells with TiO2 blocking layers and Pt counter electrodes prepared by physical vapor deposition (PVD)

Titanium dioxide (TiO2) thin films as block layers are prepared by DC reactive magnetron sputtering. X-ray diffraction (XRD) and TEM-(SAED) analyses of the films reveal that they are polycrystalline in nature and have tetragonal structure with preferred orientation along the (101) direction. The surface morphological studies by FESEM and AFM reveal the uniform surface coverage of the grains on the surface of the films. An optical transmittance value of 80% in the visible light region with the optical band gap value of 3.2 eV is measured. This sputtered TiO2 thin film is used as a blocking layer over which a thick layer of TiO2 of about 10 μm was prepared using TiO2 paste and this stack is used as the photoanode of a DSSC cell. Electron beam evaporated platinum thin film on FTO coated glass substrate is used as counter electrode. The performance of the cell with a Voc of 0.698 V, a Jsc of 6.8 mAcm−2 and an efficiency of 4.2% was achieved