Nanostructured Silicon Containing Materials Derived from Solid State Pyrolysis of Sililated Polyphosphazene Derivatives

Abstract

Pyrolysis of the silicon-containing polymer {(NP[O2C12H8])0.5[NP(OC6H4 x SiMe3)2]0.5-x [NP(OC6H5) x (OC6H4SiMe3)]x}n (1) (x = 0.13), (2) (x = 0.3), and (3) {(NP[O,2C12He])0.5[NP(OC6H4SiMe2Ph),2]0.2 [NP(OC6H5)(OC6H4SiMe2Ph)]0.3}n in air at 600 degrees C, 800 degrees C and 1000 degrees C results in the formation of nanostructured SiP,2O7, along with P4O7. The morphology as well as the size and shape of the nanostructures is observed to depend on both the mole fraction of silicon, the polymer precursor and the temperature of the pyrolysis. The first observation of nanotube formation using polyphosphazenes as a template, was noted during pyrolysis of the precursor (1) at 600 degrees C. The surface morphology of the Si or SiO2, studied by AFM, depends strongly on the crystallinity of the wafer surface used during deposition. Regular lance or point-like structures were obtained from SiP2O7 deposited on SiO2 from its precursor (2). The unique formation of micro and nanostructured SiP2O7 is discussed and a mechanism of the formation of the nanostructured materials is proposed.

Nanostructured copper oxides and phosphates from a new solid-state route

“…This corroborates our previous results that pyrolysis of organometallic derivatives of cyclotriphosphazenes yields metallic nanostructured phosphates or pyrophosphates [19][20][21][22][23][24][25][26]. The results from precursor II also corroborate this hypothesis even if no cyclophosphazenes are present since the phosphine acts as the source of phosphorus atoms.…”

“…These precursors are depicted in Scheme 1 and will be denoted throughout the paper as precursors (I) -(VII). As we previously reported, the use of metallic derivatives of phosphazenes as precursors leads to the formation of phosphorus-containing nanoparticles of phosphates or pyrophosphates [19][20][21][22][23][24][25][26]. With the aim of designing an alternative method to obtain nanostructured materials of metal oxides without using phosphorus, we show that this is possible using precursors I, II, VI and VII (see Scheme 1).…”

“…In this way, the diffraction from the grid is avoided and the observed area is minimized. The pyrolysis experiments were carried out, as previously reported [19][20][21][22][23][24][25][26], by pouring a weighed portion (0.05-0.15 g) of the solid on aluminum oxide boats placed in a furnace (Lindberg/Blue Oven model STF55346C-1) under a flow of air, heated from 25 to 300 °C and then to 800 °C, and annealed for 2 h. Raman spectra (using a 50 × objective)…”

Solid-state synthesis of embedded single-crystal metal oxide and phosphate nanoparticles and in situ crystallization

“…8 we observe that necking or coalescence of large and small nanoparticles can occur to form a larger crystalline region and can be described by Eq. [43] is a potentially useful route to a range of other nanostructured oxide and phosphate single crystal nanomaterials from transition and valve metals, particularly where nonstoichiometric phases and pyrophosphate formation is required. It constitutes a novel route to oxide and phosphate phases (at least) of multimetallic nanoparticles with potential applications ranging from interconnect metal deposition, high density surface functionalization with noble metal nanoparticles for nanocrystal embedded dielectrics, nanoparticle automotive catalysts [44,45] , surface-enhanced Raman scattering (SERS) and high lithium mobility phosphate cathode materials.…”

Organometallic Derivatives of Cyclotriphosphazene as Precursors of Nanostructured Metallic Materials: A New Solid State Method

“…We have recently reported the first solid-phase synthesis of metal nanoparticles using polyphosphazene as a hybrid inorganic-organic template [22][23][24][25], shown in Scheme 1.…”