Page 464 - Book Hosokawa Nanoparticle Technology Handbook

APPLICATIONS 5 A DYE-SENSITIZED SOLAR CELL UTILIZING METAL NANOPARTICLE
and the electronic circuit pattern formation on the sur- References
face of housing.
[1] M. Oda: J. Jpn. Inst. Electron. Packaging, 5(6),
4. Application as the joining materials 523–528 (2002).
[2] M. Nakamoto: Mater. Stage, 3(11), 35–40 (2004).
The approach of silver nanoparticle pastes to the join- [3] Y. Matsuba: J. Japn. Inst. Electron. Packaging, 6(2),
ing technique [11] has been proposed as the new type 130–135 (2003).
of lead-free solder materials in the field of microelec- [4] H. Saito, M. Ueda and Y. Matsuba: Proceedings of
tronics packaging. Silver nanoparticle pastes are used microelectronics symposium, p. 189–192 (2004).
for the copper–copper, silver–silver, and gold–gold [5] M. Nakamoto, M. Yamamoto, Y. Kashiwagi,
joinings under the condition of 300 C for 300 s and H. Kakiuchi, T. Tsujimoto and Y. Yoshida: Proceedings
the pressure at 5 MPa, resulting in the joining strength
of 40 MPa. Silver and the joining materials are joined of microelectronics symposium, p. 241–244 (2005).
through metallic binding by the firing process of the [6] Y. Ohsako: Abstract of chemical engineering, 34th
silver nanoparticle pastes at 300 C. The joining meeting, K122 (2001).
strength by silver nanoparticle pastes becomes [7] K. Murata: Mater. Stage, 2(8), 23–26 (2002).
stronger than that of the copper–copper joining by [8] M. Furusawa: SID international symposium digest of
lead-rich high temperature solders. technical papers, p. 753 (2002).
The technology of metal nanoparticle paste is now [9] K. Mizugaki, K. Wada: Proceedings of microelec-
going to be developed. Both screen printing and inkjet tronics symposium, p. 249–252 (2005).
printing show the possibility of metal nanoparticle [10] K. Koiwai, T. Sakuma, H. Kawamura, S. Yamaguchi,
pastes as the new materials for fine pitch circuit pat- K. Wada, K. Sakurada and T. Kobayashi: Proceedings
tern and multi-layers formation and also for the sys-
tem in package (SiP) [3] preparing the components of microelectronics symposium, p. 245–248 (2005).
such as capacitor, resistance, and external terminal all [11] E. Ide, S. Angata, A. Hirose and K.F. Kobayashi: Acta
at once. Mater., 53, 2385–2393 (2005).

APPLICATION 5
5 A DYE-SENSITIZED SOLAR CELL UTILIZING METAL NANOPARTICLE

In nanoparticles of metals such as silver, the “Surface TiO film sintering on the conductive glass and
2
plasmon” is excited, which involves free electrons on including a porous structure some dozens of nanome-
the surface of the nanoparticle collectively vibrating ters thick, and the other conductive glass serving as an
with irradiation of light of a specific wavelength. It is opposing electrode. A photo of the titania porous film
known that interaction with the surface plasmon of a dye-sensitized solar cell, taken by an electron
causes phenomena, such as enhancing the Raman microscope, is shown in Fig. 5.1, while a conceptual
scattering intensity of a semiconductor. diagram of the dye-sensitized solar cell (DSC) is
In this section, the following are explained: results shown in Fig. 5.2.
successfully achieved utilizing this phenomenon to The ease of production and relatively high conver-
enhance the light absorbance of a dye used for dye- sion efficiency (reportedly about 11% [1]) have raised
sensitized solar cells; the effect of enhancement in a expectations of the potential for economical and
TiO porous thin film, indispensable for enhancing highly efficient solar cells. However, even in the case
2
the efficiency of solar cells; and the potential for solar of a ruthenium dye, which is known to have excellent
cells which utilize this enhancement effect. performance as a sensitized dye, since it is adsorbed
only on the surface of the TiO porous film, the light
2
absorption coefficient of a light absorption layer is
1. What is a dye-sensitized solar cell? lower than that of semiconductors such as silicon,
which consequently hampers efforts to enhance effi-
A dye-sensitized solar cell is a wet solar cell, com- ciency. Therefore, if the light absorption coefficient
posed of two conductive glasses, filled between with of the TiO film (light absorption layer) carrying a
2
an interim electrolyte solution, one of the conductive dye could be improved, enhanced efficiency of the
glasses having a titania (TiO ) film carrying a dye, the DSC would be possible.
2
438