Wetting and drying dynamics for TiO2 with PbS quantum dots.

Abstract

Initial solar cells utilized silicon and alloys for their economic viability. Photoelectrochemical photovoltaic cells were discovered with technological advancement which increased solar efficiency and further improved economic feasibility leading to quantum dot sensitized solar cells. Lead sulfide quantum dots and titanium dioxide were studied for wetting and drying effects. Zeta potential, pH values, SEM, and optical microscopes quantified or observed the colloidal suspension and dried sample behavior. Combined mixtures of lead sulfide and titania were dried at 3.6 pH and 12.56 pH values. This due to the observed zeta potential isoelectric point of titania, and behavior showed increased stability occurring for those pH values, respectively. SEM imaging was optimized to achieve a thin layer of dried material. Lab microscope imaging further confirmed what was occurring in SEM imaging; the materials were falling out of suspension with lead sulfide settling to the bottom (black or grey material) and titania (white) on the top surface of the dried droplet at both pHs. This work completed further establishes behavioral evaluation of individual materials related to creating third generation solar devices made with quantum dots verses that of current materials used for second generation materials like CdS, CdSe, and CdTe. This work contributes to general knowledge of material characteristics of lead sulfide as a nanoparticle as a potential quantum dot in a titanium dioxide microparticle system.