Energetic characteristics of hydrogenated amorphous silicon nanoparticles

Abstract In this work, we utilize a low-temperature non-equilibrium plasma to nucleate and grow sub-10 nm Si particles with varying degrees of crystallinity by tuning the level of power coupled into plasma discharge. Temperature-programmed desorption spectroscopy shows that as-prepared amorphous Si nanoparticles (a-nSi) incorporate more hydrogen than crystalline Si nanoparticles (c-nSi). Further, hydrogen is incorporated in the material in the form of higher silicon hydrides with a lower desorption temperature. Combustion cell measurements show that when formulated with KClO4, a-nSi outperforms its crystalline counterpart with respect to pressure output. The pressurization rate of a-nSi/KClO4 composite increases by a factor of six compared with nAl to 0.66 MPa·μs−1. Evidence of hydrogen release (∼730 K) from Temperature-jump time-of-flight mass spectrometry (T-Jump TOFMS) of a-nSi/KClO4 suggests the creation of Si dangling bonds prior to ignition (∼820 K), which then react exothermically with oxygen liberated from KClO4, leading to ignition. Explosive reaction of H2/O2 mixture likely contributes to the rapid pressure rise. The enhanced energetic performance of hydrogenated a-nSi compared to its crystalline counterpart suggests that incorporation of hydrogen is a promising strategy for improving the performance of nanoenergetic materials.