Enhanced performance of dye-sensitized solar cells with TiO2blocking layers and Pt counter electrodes prepared by physical vapordeposition (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 innature and have tetragonal structure with preferred orientation along the (101) direction. The surfacemorphological studies by FESEM and AFM reveal the uniform surface coverage of the grains on the surfaceof the films. An optical transmittance value of 80% in the visible light region with the optical band gapvalue of 3.2 eV is measured. This sputtered TiO2thin film is used as a blocking layer over which a thicklayer of TiO2of about 10 �m was prepared using TiO2paste and this stack is used as the photoanode of aDSSC cell. Electron beam evaporated platinum thin film on FTO coated glass substrate is used as counterelectrode. The performance of the cell with a Vocof 0.698 V, a Jscof 6.8 mAcm−2and an efficiency of 4.2%was achieve