Synthesis of InP nanofibers from tri(m-tolyl)phosphine: an alternative route to metal phosphide nanostructures.

The synthesis of InP nanofibers via a new Ullmann-type reaction of indium nanoparticles with tri(m-tolyl)phosphine (P(PhMe)(3)) was typically performed to illustrate an alternative route for the preparation of nanostructured metal phosphides, including III-V (13-15) and transition-metal phosphides. Triarlyphosphine compounds such as other two tri(m-tolyl)phosphine isomers, diphenyl(p-tolyl)phosphine, and triphenylphosphine were comparably employed to synthesize InP nanocrystals. From the aspect of the carbonization of triarlyphosphines, Raman spectroscopy and thermo-gravimetric analysis (TGA) investigations of the InP products showed that the stability of these triarlyphosphines conformed to the order of tri(p-tolyl)phosphine approximately tri(o-tolyl)phosphine < diphenyl(p-tolyl)phosphine < tri(m-tolyl)phosphine < triphenylphosphine. The correlation between the stability of triarlyphosphines and the growth of InP nanocrystals was investigated, and experimental results showed that the relatively stable triarlyphosphines (tri(m-tolyl)phosphine and triphenylphosphine) were favorable for the preparation of one-dimensional (1D) InP nanostructures (nanofibers and nanowires). The reactivity (stability) of triarlyphosphines was also compared with those of P(SiMe(3))(3) (typically see: J. M. Nedeljković, O. I. Mićić, S. P. Ahrenkiel, A. Miedaner and A. J. Nozik, J. Am. Chem. Soc., 2004, 126, 2632) and P(C(8)H(17))(3) (C. Qian, F. Kim, L. Ma, F. Tsui, P. D. Yang and J. Liu, J. Am. Chem. Soc., 2004, 126, 1195) according to the difference in preparative temperature for phosphide synthesis. Raman and photoluminescence properties of the as-synthesized InP nanocrystals were further studied, and the synthetic mechanism of our method was reasonably investigated by GC-MS analysis. Moreover, the current route was successfully extended to prepare GaP, MnP, CoP and Pd(5)P(2) nanocrystals.