Limits...
Microscopic observation of dye molecules for solar cells on a titania surface.

Koshiya S, Yamashita S, Kimoto K - Sci Rep (2016)

Bottom Line: A single dye molecule on the titania nanosheet was visualized for the first time.The quantitative STEM images revealed an inhomogeneous dye-molecule distribution at the early stage of its absorption, i.e., the aggregation of the dye molecules.The majority of the titania surface was not covered by dye molecules, suggesting that optimization of the dye molecule distribution could yield further improvement of the DSC conversion efficiencies.

View Article: PubMed Central - PubMed

Affiliation: Surface Physics and Structure Unit, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.

ABSTRACT
The lateral distribution and coverage of Ru-based dye molecules, which are used for dye-sensitized solar cells (DSCs), were directly examined on a titania surface using high-resolution scanning transmission electron microscopy (STEM). The clean surface of a free-standing titania nanosheet was first confirmed with atomic resolution, and then, the nanosheet was used as a substrate. A single dye molecule on the titania nanosheet was visualized for the first time. The quantitative STEM images revealed an inhomogeneous dye-molecule distribution at the early stage of its absorption, i.e., the aggregation of the dye molecules. The majority of the titania surface was not covered by dye molecules, suggesting that optimization of the dye molecule distribution could yield further improvement of the DSC conversion efficiencies.

No MeSH data available.


Related in: MedlinePlus

Experimental and simulated ADF images of titania nanosheet.(a) ADF image of monolayer titania nanosheet. The line profile of A–A′ is shown in inset. (b,c) Experimental (b) and simulated (c) ADF image of monolayer titania nanosheet. The directions of the a and b axes are indicated in (b,c). The intensity of these images is given as the quantitative ADF contrast QADF, and the QADF scales for the experimental and simulated images were set in the same range of 0–0.5%. The mean quantitative contrasts of the monolayer titania nanosheet in (a–c) are 0.25 ± 0.01%, 0.21 ± 0.01%, and 0.28%, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4834531&req=5

f1: Experimental and simulated ADF images of titania nanosheet.(a) ADF image of monolayer titania nanosheet. The line profile of A–A′ is shown in inset. (b,c) Experimental (b) and simulated (c) ADF image of monolayer titania nanosheet. The directions of the a and b axes are indicated in (b,c). The intensity of these images is given as the quantitative ADF contrast QADF, and the QADF scales for the experimental and simulated images were set in the same range of 0–0.5%. The mean quantitative contrasts of the monolayer titania nanosheet in (a–c) are 0.25 ± 0.01%, 0.21 ± 0.01%, and 0.28%, respectively.

Mentions: Titania nanosheets in a colloidal suspension are surrounded by tetrabutylammonium (TBA, (C4H9)4N+) ions, which can be removed by photocatalytic reaction, resulting in free-standing nanosheets with clean surfaces (see Methods and Supplementary Figs S1–S4). Here, we confirm the crystal structure of the pristine titania nanosheets using high-resolution ADF imaging, which has not been previously achieved. Figure 1a presents the ADF images, whose quantitative contrasts QADF were scaled by the ratio of the ADF signal to the incident electron intensity18. As demonstrated in the inset in Fig. 1a, the intensity profile along A–A′ exhibits a stepwise feature; the averaged intensities are 0%, 0.25%, and 0.46%, which are considered to be the vacuum, monolayer, and bilayer areas, respectively. The numbers of the titania nanosheet layers could be counted using quantitative ADF imaging.


Microscopic observation of dye molecules for solar cells on a titania surface.

Koshiya S, Yamashita S, Kimoto K - Sci Rep (2016)

Experimental and simulated ADF images of titania nanosheet.(a) ADF image of monolayer titania nanosheet. The line profile of A–A′ is shown in inset. (b,c) Experimental (b) and simulated (c) ADF image of monolayer titania nanosheet. The directions of the a and b axes are indicated in (b,c). The intensity of these images is given as the quantitative ADF contrast QADF, and the QADF scales for the experimental and simulated images were set in the same range of 0–0.5%. The mean quantitative contrasts of the monolayer titania nanosheet in (a–c) are 0.25 ± 0.01%, 0.21 ± 0.01%, and 0.28%, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834531&req=5

f1: Experimental and simulated ADF images of titania nanosheet.(a) ADF image of monolayer titania nanosheet. The line profile of A–A′ is shown in inset. (b,c) Experimental (b) and simulated (c) ADF image of monolayer titania nanosheet. The directions of the a and b axes are indicated in (b,c). The intensity of these images is given as the quantitative ADF contrast QADF, and the QADF scales for the experimental and simulated images were set in the same range of 0–0.5%. The mean quantitative contrasts of the monolayer titania nanosheet in (a–c) are 0.25 ± 0.01%, 0.21 ± 0.01%, and 0.28%, respectively.
Mentions: Titania nanosheets in a colloidal suspension are surrounded by tetrabutylammonium (TBA, (C4H9)4N+) ions, which can be removed by photocatalytic reaction, resulting in free-standing nanosheets with clean surfaces (see Methods and Supplementary Figs S1–S4). Here, we confirm the crystal structure of the pristine titania nanosheets using high-resolution ADF imaging, which has not been previously achieved. Figure 1a presents the ADF images, whose quantitative contrasts QADF were scaled by the ratio of the ADF signal to the incident electron intensity18. As demonstrated in the inset in Fig. 1a, the intensity profile along A–A′ exhibits a stepwise feature; the averaged intensities are 0%, 0.25%, and 0.46%, which are considered to be the vacuum, monolayer, and bilayer areas, respectively. The numbers of the titania nanosheet layers could be counted using quantitative ADF imaging.

Bottom Line: A single dye molecule on the titania nanosheet was visualized for the first time.The quantitative STEM images revealed an inhomogeneous dye-molecule distribution at the early stage of its absorption, i.e., the aggregation of the dye molecules.The majority of the titania surface was not covered by dye molecules, suggesting that optimization of the dye molecule distribution could yield further improvement of the DSC conversion efficiencies.

View Article: PubMed Central - PubMed

Affiliation: Surface Physics and Structure Unit, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.

ABSTRACT
The lateral distribution and coverage of Ru-based dye molecules, which are used for dye-sensitized solar cells (DSCs), were directly examined on a titania surface using high-resolution scanning transmission electron microscopy (STEM). The clean surface of a free-standing titania nanosheet was first confirmed with atomic resolution, and then, the nanosheet was used as a substrate. A single dye molecule on the titania nanosheet was visualized for the first time. The quantitative STEM images revealed an inhomogeneous dye-molecule distribution at the early stage of its absorption, i.e., the aggregation of the dye molecules. The majority of the titania surface was not covered by dye molecules, suggesting that optimization of the dye molecule distribution could yield further improvement of the DSC conversion efficiencies.

No MeSH data available.


Related in: MedlinePlus