Doping effects of higher fullerene in conducting polymer

Doping effects of higher fullerenes such as C70 on electrical and optical properties of conducting polymers such as poly(3-alkylthiophene), poly(2,5-dialkoxy-p-phenylene vinylene) and poly(9,9-dialkylfluorene) have been studied and compared with those by C60 doping. Fluorescence intensity was quenched and photoconductivity was enhanced upon doping of higher fullerenes in the conducting polymers just as the case of C60 doping. However, there also exist differences in detailed aspects in quenching of photoluminescence and enhancement of photoconductivity between C60 doping and higher fullerenes dopings. These results are interpreted by taking into account the electronic energy states of C60 and higher fullerenes.