Methods are disclosed of making linear and cross-linked, HMW (high molecular weight) polysilanes and polygermanes, polyperhydrosilanes and polyperhydrogermanes, functional liquids containing the same, and methods of using the liquids in a range of desirable applications. The
silane and
germane polymers are generally composed of chains of Si and / or Ge substituted with R′ substituents, where each instance of R′ is, for example, independently
hydrogen,
halogen, alkenyl, alkynyl, hydrocarbyl, aromatic hydrocarbyl, heterocyclic aromatic hydrocarbyl, SiR″3, GeR″3, PR″2, OR″, NR″2, or SR″; where each instance of R″ is independently
hydrogen or hydrocarbyl. The cross-linked polymers can be synthesized by dehalogenative
coupling or dehydrocoupling. The linear polymers can be synthesized by ring-opening
polymerization. The polymers can be further modified by
halogenation and / or reaction with the source of
hydride to furnish perhydrosilane and perhydrogermane polymers, which are used in liquid ink formulations. The synthesis allows for tuning of the liquid properties (e.g.,
viscosity, volatility, and
surface tension). The liquids can be used for deposition of films and bodies by spincoating, inkjetting, dropcasting, etc., with or without the use of UV
irradiation. The deposited films can be converted into amorphous and
polycrystalline silicon or
germanium, and
silicon or
germanium oxide or
nitride by curing at 400-600 DEG C. and (optionally)
laser- or heat-induced
crystallization (and / or
dopant activation, when
dopant is present).