Trisilane, isotetrasilane, neopentasilane, and cyclohexasilane have been prepared in gram scale. In‐situ cryo crystallization of these pyrophoric liquids in sealed capillaries on the diffractometer allows access to the single crystal structures of these compounds. Structural parameters are discussed and compared to gas‐phase electron diffraction structures from literature and with the results from quantum chemical calculations. Significantly higher packing indices are found for the silanes compared to the corresponding alkanes. Radiation with ultraviolet light (365 nm) and parallel ESR (EPR) measurement shows that cyclohexasilane is easily split into radicals, which subsequently leads to the formation of branched and chain‐like oligomers. The other compounds form no radicals under these conditions. NMR spectra of all four compounds have been recorded.

Disproportionation reactions of Si 2 Cl 6 in the presence of [nBu 4 N]Cl in halogenated solvents yield the compound [nBu 4 N][C(SiCl 3 ) 3 ](1). X-ray structure analysis of 1 proves the existence of a planar carbanion, which is stabilized by three trichlorosilyl groups. Quantum chemical analysis shows the [a] 5028 presence of highly polar bonds in the anion. Planarization of the anion can be explained by the interaction of the occupied lone pair at the carbon atom with the antibonding σ* orbitals of the Si-Cl bonds (negative hyperconjugation).

Branched higher silicon hydrides Si n H2n+2 with n > 6 were recently found to be excellent precursors for the liquid phase deposition of silicon films. Herein we report the gram-scale synthesis of the novel nona- and decasilanes (H3Si)3Si­(SiH2) n Si­(SiH3)3 (2: n = 1, 5: n = 2) from (H3Si)3SiLi and Cl­(SiPh2) n Cl by a combined salt elimination/dephenylation/hydrogenation approach. Structure elucidation of the target molecules was performed by NMR spectroscopy and X-ray crystallography. 2 and 5 are nonpyrophoric and exhibit a bathochromically shifted UV absorption compared to neopentasilane and the structurally related octasilane (H3Si)3SiSi­(SiH3)3. TG–MS analysis elucidated increased decomposition temperatures and decreased ceramic yields for branched hydrosilanes relative to cyclopentasilane. Otherwise, very similar thermal properties were observed for hydrosilane oligomers with linear and branched structures.

Cyclopentasilane (CPS) has been studied as an liquid precursor for the deposition of thin silicon films for printed electronics and related applications. The processing involves a UV‐induced prepolymerization of CPS followed by liquid deposition and low‐temperature thermolysis. An insight into the oligomer and polymer formation including crosslinking in solution using 29Si NMR spectroscopy and electron spin resonance spectroscopy is reported. Formation of SiH (T‐units) and SiH3 (M‐units) is observed as well as short‐lived paramagnetic species. Additionally, the polymerization is followed by Raman spectroscopy. Reactive molecular dynamics simulations are applied to develop a theoretical model for the CPS‐ring‐opening and crosslinking steps. The experimental and computational data correspond well to each other and allow insight into the mechanism of polymer formation. The processing steps include spin‐coating, thermal drying, and conversion to amorphous silicon, H‐passivation, and fabrication of a CPS‐derived thin‐film transistor (TFT), without intermediate silicon crystallization. Further improvement is gained by using tetralene as a solvent, leading to a reduction of the time‐consuming polymerization step by one order of magnitude compared to cyclooctane. The overall quality and characteristics of the CPS‐derived spin‐coated silicon thin films correspond to standard plasma enhanced chemical vapor deposition‐derived devices with respect to performance levels.

A novel and cost-effective synthesis of silicon nanocrystallites (<10 nm) sealed in hollow carbon spheres (nc-Si@HCS) is developed as a promising anode material for high-performance Li-ion batteries (LIBs). The preparation method involves dichlorosilane (H2SiCl2) as widely available feedstock, to form a hydrogen-rich polysiloxane as a precursor for the production of large quantities of silicon nanoparticles. The final electrode material is composed of agglomerated 5 nm sized silicon nanoparticles encapsulated within hollow micro-sized carbon structures. A high specific capacity of 1570 mA h gelectrode−1 at 0.25 A g−1 with a capacity retention of 65% after 250 deep discharge cycles and a reversible high areal capacity of up to 4 mA h cm−2 at a total mass loading of 3.2 mg cm−2 impressively demonstrate the excellent features of this novel anode material. We performed a detailed structural as well as electrochemical characterization in different electrolytes. Post mortem investigations help to understand the degradation mechanism in our material. The study herein heralds a new approach to structurally design advanced negative electrode materials with the potential to increase the specific energy of LIBs and to boost future electro-mobility technology