Sonophotolytically Synthesized Silicon Nanoparticle‐Polymer Composite Ink from a Commercially Available Lower Silane

Abstract

The preparation of a printable silicon ink using semiconductor grade and commercially available trisilane (Si3H8) is reported. The synthesis is carried out in solution at room temperature or below in N2 atmosphere at ambient pressure and involves an initial sonication step, followed by irradiation with ultraviolet light. The production of higher order silanes via ultrasound is demonstrated using gas chromatography and nuclear magnetic resonance measurements are used to show that a combined sonophotolytic treatment yields a highly branched silicon hydride polymer. In addition, scanning electron microscopy (SEM) images are used to ascertain the sonocatalytic production of silicon nanoparticles. Furthermore, it is argued that these particles are partially responsible for enabling dramatically accelerated polymer growth, not otherwise observed in the same amount of time using ultraviolet light alone. Finally, the utility of the ink used in this study is demonstrated for the field of printable electronics by fabricating amorphous silicon thin films by spin‐coating and atmospheric pressure chemical vapor deposition with optoelectronic properties approaching those of state‐of‐the‐art plasma enhanced chemical vapor deposition (PECVD) material.

Syntheses and Molecular Structures of Liquid Pyrophoric Hydridosilanes

“…The higher homologues of these compounds are seldom used, since they are difficult to handle and pyrophoric. However, the chemistry of hydridosilanes has received a considerable revival in recent years due to their potential use as precursors for liquid phase deposition of silicon films . This approach promises significant reduction of processing costs in the manufacture of semiconductor devices .…”

From Cyclopentasilane to Thin‐Film Transistors

“…After a heat treatment step at comparatively low temperatures between 300 and 500 °C, very pure a:Si films are obtained for processing into electronic devices. In the past decade, many research groups dealt with different hydrosilane precursors like CPS, [ 2 ] CHS, [ 7 ] trisilane, [ 8 ] and NPS [ 9 ] and its derivatives [ 10 ] to form silicon thin films. A detailed structural comparison including single‐crystal X‐ray structures of trisilane, isotetrasilane, CHS, and NPS has recently been published.…”

Approaching Solar‐Grade a‐Si:H for Photovoltaic Applications via Atmospheric Pressure CVD Using a Trisilane‐Derived Liquid Precursor

“…The contribution to film growth from the first two likely takes place via a combination of pyrolytic decomposition reactions and conversion (cross‐linking) into a‐Si:H at the surface of the substrate, respectively . Their presence also helps lower the effective thermal decomposition temperature of the ink and hence increase the film growth rate during APCVD . Through their transport in micro droplets and subsequent embedding into the growing film, we suspect that the Si‐NPs likewise enhance the growth rate (further details in the Supporting Information).…”

“…Intrinsic and doped inks have previously been synthesized from a variety of different monomers, these include the cyclic silanes cyclopentasilane (CPS, Si 5 H 10 ) and cyclohexasilane (CHS, Si 6 H 12 ), and the branched molecule neopentasilane (NPS, Si 5 H 12 ) . Solution‐processed a‐Si:H layers have been deposition via inkjet printing, spin coating, slot die coating, atmospheric pressure chemical vapor deposition (APCVD), and aerosol‐assisted APCVD (AA‐APCVD) . The functional optoelectronic applications of such layers include thin‐film transistors, thin‐film solar cells, c‐Si surface passivation layers, and patterned films via imprinting .…”

“…As demonstrated in a previous publication and schematically outlined in Figure , the entire ink preparation and layer deposition are carried out in a N 2 ‐filled glove box. The synthesis route and silicon precursor used in the fabrication of our ink differ from the conventional methods found in the literature.…”