Scanning Tunneling Microscopy Study of Black Dye and Deoxycholic Acid Adsorbed on a Rutile TiO₂(110)

Abstract

Trithiocyanato(4,4',4''-tricarboxy-2,2':6',2''-terpyridine)ruthenium(II), "black dye", was adsorbed on a rutile TiO(2)(110) surface and imaged by an ultrahigh vacuum scanning tunneling microscope. The TiO(2)(110)-(1 x 1) surface was prepared in a vacuum, covered with pivalate monolayer, and immersed in acetonitrile containing black dye. Black dyes exchanging preadsorbed pivalates were observed on the surface as protrusions with lateral dimensions from 2 to 10 nm. Protrusions with a minimum lateral dimension of 2 nm were assigned to single, isolated black dyes, and larger protrusions were attributed to aggregated dyes. When deoxycholic acid was added to the dye solution, the number ratio of the single dyes to the aggregated dyes increased, while adsorbed deoxycholic acid was not observed.

Acid Treatment of Titania Pastes to Create Scattering Layers in Dye-Sensitized Solar Cells

“…Firstly, the pore size drops from ca 40 nm to around 10-15 nm on immersion in acid for 60 minutes. Since the dye itself typically has a size of ca 2 nm [25] this will result in poor dye uptake which aligns with the observations of lower coloration of the acid exposed face shown in Figure 4. In addition the data shows an expanded pore size at larger values (ca 200 nm) and above which correlates with the FEGSEM images and leads to the scattering effect.…”

Quasi Solid-State Dye-Sensitized Solar Cell Incorporating Highly Conducting Polythiophene-Coated Carbon Nanotube Composites in Ionic Liquid

“…The electrodes were impregnated with a 0.05 M titanium tetrachloride solution and sintered at 500 • C. A dye solution of 3 × 10 −4 M N719 was prepared in 1 : 1 acetonitrile and tert-butyl alcohol solvents. Deoxycholic acid (20 mM) was added to the dye solution as a coadsorbent to prevent aggregation of the dye molecules [31,32]. The electrodes were immersed in the N719 solution and then kept at 25 • C for 20 h to adsorb the dye onto the TiO 2 surface.…”

Self-Organized One-DimensionalTiO2Nanotube/Nanowire Array Films for Use in Excitonic Solar Cells: A Review

“…N-719 dye forms a nonagglomerated monolayer [104]. Since black dye agglomerates, coadsorption of deoxycholic acid was employed to form the black dye coating and reduce agglomeration [105]. The dilution of black dye in the monolayer reduced the concentration of acceptors available for energy transfer and resulted in lower critical distance and lower energy transfer efficiencies for black dye relative to N-719 despite the higher spectral overlap of black dye absorption with the emission spectrum of ZnPc.…”