Abstract: The nonlinear optical(NLO) properties of [Mo₆O₁₉]^2-decorated single wall carbon nanotubes(SWCNT) were investigated by density functional theory(DFT). These special organic-inorganic hybrids possess a large second-order NLO response. It is noteworthy that the second-order NLO behavior can be switched by the variable angle between [Mo₆O₁₉]^2- and CNT and the stability of systems shows the regular trends. The characteristic of the charge-transfer transition corresponding to the dominant contributions to the static second-order polarizibility(β_vec) values indicates that the variable anchoring angles of [Mo₆O₁₉]^2- can influence the intramolecular donor or acceptor character. When the anchoring angle of [Mo₆O₁₉]^2- becomes 30°, the complex exhibits the largest β_vec value; besides, the polyoxometalate(POM) cluster acts as the acceptor and the CNT as the donor. Furthermore, the incorporation of an electron donor(the amido group) leads to a larger β_vec value at the end of the CNT segment.

Key words: Carbon nanotube, Polyoxometalate, Second-order nonlinear optical property, Density functional theory