DEVELOPMENT OF NANOSTRUCTURED MATERIALS FOR SOLAR CELL APPLICATIONS

Abstract

The present work is based on the synthesis of nanostructures of wide band gap semiconductor material “titania” using sol gel refluxing method for the application in dye sensitized solar cells (DSSC). The precursor Titanium Tetraisopropoxide (TTIP) was modified by acetic acid giving Titanium Acetato Tris Isopropoxide (TATIP) and acetyl acetone giving Titanium Acetylacetonato Tris Isopropoxide (TAATIP). The effect of refluxing time (24 hrs (Tit 1, Ta 1), 70 hrs (Tit 2, Ta 2) and 120 hrs (Tit 3)) as well as precursor modifier on synthesis of titania was studied. The characterized nanoparticles were then used to make sintered films over TCO coated glass to make photoanode of DSSC. The characterization was performed using XRD, surface area measurement by BET method, TGA/DTA and SEM. Anatase phase is predominant in all the samples. The particle size range in annealed films is from 50 to 70 nm. In Tit 1 film there are about 500 nm sized spongy particles having around 50 nm sized pores. In Tit 2 although the particle size is in the same 50 nm range but they are clustered showing poor porosity and low surface area, in Tit 3 there are well dispersed particles of diameter around 50 nm. The film has high porosity and also there is proper connectivity between the particles to allow the efficient charge flow if used as photoanode. The best results were obtained from nanoparticles prepared by acetic acid modification and refluxing time of 120 hours (Tit 3), also the film obtained from Tit 1 (24 hr reflux) offers good porosity and linking among the particles but it is not so continuous at micro and macro level. The film from Tit 3 was then used to make a prototype DSSC and its testing was performed.