Theoretical studies on the electronic structures and spectra of single silicon-doped SWCNTs

Abstract

Abstract:The equilibrium geometries and electronic structures of a series of SWCNTs doped with a silicon atom were studied by using density function theory (DFT). The most stable doping site of silicon predicted at B3LYP/6-31G(d,p) level was located near the boundary of the SWCNTs. The energy gaps of (3,3) C 48 , (3,3) C 60 and (3,3) C 72 were respectively decreased by 0.43, 0.25 and 0.14 eV after doping. Based on the B3LYP/6-31G(d) optimized geometries, the electronic spectra of the doped SWCNTs were computed using the INDO/CIS method. The first UV absorption at 973.9 nm of (5,5)-Si(L) (C 59 Si) compared with that at 937.5 nm of (5,5) (C 60 ) was red-shifted. The