N719 Sensitized Solar Cell Features of Photoanodes Prepared with CDS Coated Hydrothermally Derived Anatase Tio2 Nanobelts

Abstract

Herein, DSSC performance of the photo-anodes of (i) TiO2 powders derived from simple basic precipitation (SP) reaction (SP-TiO2-1), (ii) TiO2 powders derived from conventional hydrothermal reaction (CH-TiO2-2) and (iii) hydrothermally derived TiO2 coated with CdS by dip method (CdS-CH-TiO2-3) is reported. The XRD, UV-visible spectroscopy, FESEM and HRTEM techniques are used for the characterization of resultant films. The characterization studies indicated the crystallization of anatase TiO2 in all resultant films and CdS with hexagonal symmetry in case of CdS-CH-TiO2-3 film. The crystallization of spherical agglomerates having average size of 36.05 nm with nearly uniform size distribution is realized in case of SP-TiO2-1 by using FESEM. Further, HRTEM indicated the coating of CdS nanoparticles with average particle size of 15.86 nm on hydrothermally crystallized anatase TiO2 nanobelts of width 200 nm in case of CdS-CH-TiO2-3 films. The N719 sensitized solar cell properties these photoanodes obtained at 1000 W/m2 input power indicated the enhancement of photoconversion efficiency (η) by 95.83 % in case of CH-TiO2-2 (η = 1.41) as compared to SP-TiO2-1 (η = 0.72) photoanode whereas 34.75 % in case of CdS-CH-TiO2-3 (η = 1.90) as compared to CH-TiO2-2 photoanode. The improvement in photoconversion efficiency (η) in case of CH-TiO2-2 and CdS-CH-TiO2-3 can be attributed due to increase in charge transfer current density (J) and decrease in re-combination rate of electron at electrode-electrolyte/dye contact. This is due to blocking of back scattered electrons and effective electron-hole charge separation created by co-sensitizer CdS nanoparticles coated on TiO2 nanobelts.