Pentagon formation induced by BN co-doping in graphite

Shimoyama, Iwao; Baba, Yuji; Sekiguchi, Tetsuhiro; Uddin, M. N.*; Nagano, Masamitsu*

no journal, , 

Heteroatom doping has been expected to control properties of carbon materials. However, the correlation between structures and bulk properties has not been well clarified because of the complicated structures around dopants. We studied local structure of B- and N-doped graphite by NEXAFS spectroscopy and molecular orbital calculations. Multiple peaks in NEXAFS spectra showed graphite-like polarization dependence. Among them, the peak of h-BN had larger polarization dependence than the other peaks of BCN moiety. We considered that the decrease of polarization dependence is attributed to distorted planar structure which includes pentagon. To verify this idea, we compared structural stabilities of two kinds of model clusters. Heat of formation of the model clusters showed that buckled structures become more stable by B and N co-doping than before doping. This supports our idea that pentagon is introduced by BN co-doping in graphite.