Performance analysis of dye sensitized solar cells annealed by microwave processing

Abstract

In the present work Dye sensitized solar cells (DSSCs), sensitized with natural newlinecoloring pigments extracted from Argemona Mexicana, Grapes, Beta vulgaris, Piper newlinebetel leaves Spinach leaves and red Malabar spinach fruit were prepared. These dyes newlinewere prepared using ethanol as solvent. Different dye extracts were used as sensitizer newlinefor the photo electrode and incorporated in the DSSCs. UV-Visible spectra were newlinerecorded for the different natural dyes and the corresponding peak absorbance newlinewavelength, absorbance, photon energy and absorption coefficient for the dyes were newlinecalculated. UV-Visible spectra show varying peak absorbance wavelength ranging newlinefrom 328 to 544 for different dyes used. Functional group present in the dyes were newlineidentified using FTIR studies as intermolecular hydrogen bond (H-bond)., C-H newlinestretching bonds, C=C stretching bonds and CO-O-CO stretching bonds. Different newlineDSSCs were prepared under same processing condition and by using different newlinenatural dyes. These DSSCs were calcined using conventional heating method. Photoelectrochemical newlineperformances of these DSSCs were evaluated under a scanning newlinevoltage +1 V to -1V. The short circuit current (ISC) varies from 7.5 to 2.45 mA, with newlineopen circuit voltage (VOC) ranging from 0.25 to 0.42 V and efficiency of Beta newlinevulgaris, Betel leaves, Grapefruit, Spinach leaves and Argemona Mexicana flower newlineare 1.20,1.22 ,1.46, 1.64 and 1.29 respectively for the 100 mW/cm2 light intensity. newlineThis reveal DSSCs prepared using dyes extracted from Beetle leaves show least newlineefficiency and the DSSC prepared using spinach showing increased efficiency. newlineThe cells were fabricated using TiO2 as semiconducting newlinelayer deposited on the transparent fluorine doped tin oxide (FTO) conductive glass. newlineMicrowave processing is used for annealing the TiO2 coated FTO glass, keeping newlineconstant microwave power and by varying microwave exposure times from 1 to 10