A high-throughput method is presented for the efficient assessment of the formation and stability of nanoparticle suspensions in ionic liquids which differ in their cations and anions. As a proof of principle, Ag was sputtered on a cavity array filled with 9 different ionic liquids. Not all nanoparticle ionic liquid combinations form a stable suspension with separated nanoparticles. Directly after synthesis, the formation of nonagglomerated nanoparticle suspensions with sizes from 4 to 9 nm is observed by transmission electron microscopy as well as different time dependencies of the suspension stabilities. Only 3 out of the tested 9 nanoparticle ionic liquid suspensions show long-term stability: Stable suspension of spherical nanoparticles are formed in the ionic liquids 1-butyl-3-methylimidazolium bis(perfluoroethylsulfonyl)imide [Bmim][(Pf)2N], 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [Bmim][(Tf)2N], and 1-butyl-1-methylpyrrolidinum bis(trifluoromethylsulfonyl)imide [BmPyr][(Tf)2N].
Keywords: combinatorial methods; high-throughput characterization; ionic liquids; silver nanoparticles; sputter deposition.