Layered graphitic carbon host formation during liquid-free solid state growth of metal pyrophosphates

We report a successful ligand- and liquid-free solid state route to form metal pyrophosphates within a layered graphitic carbon matrix through a single step approach involving pyrolysis of previously synthesized organometallic derivatives of a cyclotriphosphazene. In this case, we show how single crystal Mn2P2O7 can be formed on either the micro- or the nanoscale in the complete absence of solvents or solutions by an efficient combustion process using rationally designed macromolecular trimer precursors, and present evidence and a mechanism for layered graphite host formation. Using in situ Raman spectroscopy, infrared spectroscopy, X-ray diffraction, high resolution electron microscopy, thermogravimetric and differential scanning calorimetric analysis, and near-edge X-ray absorption fine structure examination, we monitor the formation process of a layered, graphitic carbon in the matrix. The identification of thermally and electrically conductive graphitic carbon host formation is important for the further development of this general ligand-free synthetic approach for inorganic nanocrystal growth in the solid state, and can be extended to form a range of transition metals pyrophosphates. For important energy storage applications, the method gives the ability to form oxide and (pyro)phosphates within a conductive, intercalation possible, graphitic carbon as host–guest composites directly on substrates for high rate Li-ion battery and emerging alternative positive electrode materials

Electrical properties of platinum interconnects deposited by electron beam induced deposition of the carbon-free precursor, Pt(PF3)4

Comprehensive analysis of the electrical properties, structure and composition of Pt interconnects, developed via mask-less, electron beam induced deposition of the carbon-free Pt precursor, Pt(PF3)4, is presented. The results demonstrate significantly improved electrical performance in comparison with that generated from the standard organometallic precursor, (CH3)3Pt(CpCH3). In particular, the Pt interconnects exhibited perfect ohmic behavior and resistivity that can be diminished to 0.24 × 10−3 Ω cm, which is only one order of magnitude higher than bulk Pt, in comparison to 0.2 Ω cm for the standard carbon-containing interconnects. A maximum current density of 1.87 × 107 A cm−2 was achieved for the carbon-free Pt, compared to 9.44 × 105 A cm−2 for the standard Pt precursor. The enhanced electrical properties of the as-deposited materials can be explained by the absence of large amounts of carbon impurities, and their further improvement by postdeposition annealing in N2. In-situ TEM heating experiments confirmed that the annealing step induces sintering of the Pt nanocrystals and improved crystallinity, which contributes to the enhanced electrical performance. Alternative annealing under reducing conditions resulted in improved performance of the standard Pt interconnects, while the carbon-free deposit suffered electrical and structural breakage due to formation of larger Pt islands