Nanomaterials: Properties, Preparation and Applications - Environmental and Human Health Impacts of Nanotechnology - page 69

Table 2.5 A list of used and proposed nanomaterials for dye sensitised solar cell (DSSC)
and thin fi lm solar cell devices.

Material Formula Cell type Reference

Cadmium telluride CdTe Thin fi lm a

Cadmium sulfi de CdS Thin fi lm a

Copper indium gallium selenide CuIn x Ga (1 − x) Se 2 Thin fi lm a

Fullerenes C 60 Thin fi lm b

Cadmium selenide CdSe Thin fi lm c

Copper indium selenide CuInSe 2 Thin fi lm c

Indium sulfi de InSe Thin fi lm c

Zinc oxide ZnO Thin fi lm & DSSC c & d

Titanium dioxide TiO 2 DSSC e

References: a: Elliott and Zhang, 2001; b: Afzaal and O'Brien, 2006; c: Hua and Dong, 2007; d: Li et al. , 2006;
e: Nohynek et al. , 2007.

candidates for the decomposition of organic wastes, especially chloro-hydrocarbons
(Wang and Zhang, 1997; Phenrat et al. , 2007). Field tests of these materials have
shown that they can be effi cient in decomposing these contaminants. However,
there is some concern regarding the depletion of dissolved oxygen during treatment
(Elliott and Zhang, 2001). Similar results are now being reported for nickel/iron
nanoparticles (Tee et al. , 2005). Titanium dioxide has also been used in self-cleaning
glass (Parkin and Palgrave, 2005) and waste water treatment (Andersson et al. ,
2002). Both of these applications depend on the ability of titanium dioxide to pho-
tolytically generate radicals which can then catalyse the decomposition of organic
materials.

2.6.2.5 Fuel Additives

The use of cerium oxide has been shown to improve the effi ciency of diesel fuels
vehicles by up to 11%. Ceria nanoparticles are currently manufactured commer-
cially have been tested on some coaches used in normal service. The reported
results show excellent properties in increasing fuel effi ciency and reduction in the
production of ultrafi ne particles (UFPs).

2.6.2.6 Bactericides

Nanoparticles of silver have been generally suggested as suitable biocidal materials.
These would have the advantage over silver salts because they may be immobilised
in a material and therefore not be consumed with time. Whilst there are several
products on the market at the moment, the exact mechanism of the biocidal effects
has yet to be determined and current speculation suggests either a radical mecha-
nism causing cell death or possible immobilisation of sulfur containing proteins
(Kim et al. , 2007 ; Jeon et al. , 2003). Either mechanism seems possible and should
also include the possibility of dissolution of silver ions from the nanoparticles