Fullerene bisadducts for organic photovoltaics

PhD ceremony: Mr. R.K.M. Bouwer, 12.45 uur, Senaatskamer Academiegebouw, Broerstraat 5, Groningen

Dissertation: Fullerene bisadducts for organic photovoltaics

Promotor(s): prof. J.C. Hummelen

Faculty: Mathematics and Natural Sciences

In 1985 the discovery of a soluble form of carbon, the so-called fullerenes, started a new, still expanding field of research in chemistry. Carbon exist naturally in different forms, the so-called allotropes of carbon; graphite (the well know black carbon), diamond and fullerene. Fullerenes are spherical molecules existing entirely of carbon atoms. A fourth form are the so-called carbon nanotubes; tubular carbon molecules.

Fullerenes are a very suitable material for electronics, for they are exceptionally good in accepting and conducting electrons. Electrics based on organic molecules is called organic electronics. Examples of organic electronics include organic transistors, organic LEDs (OLEDs), and organic solar cells, which are the subject of this thesis.

Because fullerenes do not have all the properties desired for use in organic solar cells, they need to be modified first. We can differentiate between three groups of modified fullerenes. Those with only one side group attached to the ball, so-called monoadducts, those with two side groups, so-called bisadducts, or even more side groups attached to the ball, so-called higher adducts.

In this thesis the emphasis is on the development of fullerene bisadducts and their use as electron accepting material in organic solar cells. This form of modified fullerenes is only recently being used in solar cells. Therefore little is yet known about the properties and performance of such materials. With this thesis a contribution to the understanding and further development of this promising class of material is made.