Enhanced efficiency of CdS/P3HT hybrid solar cells via interfacial modification

Abstract

The present paper examines the effects of surface modification of CdS with diverse dyes on fabricated CdSbasedhybrid solar cells. The X-ray diffraction results showed that CdS thin films had a hexagonal phase with a preferredorientation along the (101) plane. Scanning electron microscopy indicated that the CdS specimen was composed of agranular structure while a P3HT layer was formed from tiny grains. Band gaps of the CdS thin films and the P3HT layerwere 2.45 eV and 1.98 eV, respectively. The absorption spectra showed that different dye loading caused an increase inthe absorbance of CdS thin films in the wavelength range of 400–650 nm. The photoluminescence of the CdS/P3HTstructure including various dyes was lower than that of the pristine one, implying that efficient charge separation wasachieved upon surface modification. Current density–voltage curves showed that the ITO/CdS/N719/Ag hybrid solarcell exhibited the best overall efficiency of 0.082%, which can be attributed to improvements in both short circuit currentdensity (Jsc) and open circuit voltage (Voc) . These enhancements can be attributed to the creation of better interfacialcontact between CdS and P3HT layers after dye loading.