The Preparation of Other Chalcogenides and Pnictide Nanomaterials - Semiconductor Quantum Dots: Organometallic and Inorganic Synthesis - page 108

resulting solid using acetone. The resulting hollow Ni 2 P particles were 5 - 15

nm in diameter, with a wall thickness of 2 3 nm. Further work revealed that

nickel particles formed initially, which then reacted with the phosphorus,
forming an Ni 2 P layer through which the remaining nickel di

-

used, reacting
with the available reagents, forming the hollow particle. Tributylphosphine
(TBP) was also found to work as a precursor, and CoP hollow spheres were
prepared in a similar manner. A detailed study reported the P : Ni ratio was
a key factor in determining the product outcome using essentially the same
reaction. 100 A ratio of 1 : 3 resulted in nickel particles forming below 240 C,
converting to the hollow mixed-phase Ni 2 P/Ni 12 P 5 particles at 300 C and
above. Reactions with a ratio of 1 : 6 were found to generate a mixture of
hollow and solid mixed-phase particles, whereas reactions with a larger ratio
(>1 : 9), resulted in a Ni

d n 1 y 4 n g | 2

TOP complex, and ultimately in the direct synthesis
of the mixed phase which was amorphous below 240 C and crystalline above
300 C. Again TBP was found to be an e

-

ective precursor as was triphenyl-
phosphine. The use of TOPO instead of TOP did not generate the phosphide,
but did improve the solubility of the product when compared to the use of
ODE. Triphenylphosphine was again used in a similar study, resulting in the
formation of Ni/Ni 2 P core/shell particles by preparing nickel particles at
200 C followed by the reaction with the surface triphenylphosphine ligand at
280 C, giving the core/shell structure. 101 The reduced temperature can be
used to explain the di

ering reaction product. Solid Ni 2 P particles have
also been made by the reaction of either nickel particles or Ni(C 8 H 12 ) 2
with P 4 . 102,103
In this chapter, we have shown how the chemistry described previously can
be applied to the synthesis of more unusual materials. This demonstrates
how general the chemistry is and how most materials should be accessible
using the synthetic pathways described.

.

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