Ole-ain't: Trialkyl oxonium salts are universal reagents for native-ligand stripping of carboxylate- (e.g., oleate-), phosphonate-, and amine-passivated nanocrystal thin films and dispersions to give bare or BF 4 -/DMF-passivated surfaces. Meerwein-activated PbSe nanocrystal thin films (see picture) show hole mobilities of about 2-4 cm 2 V -1 s -1, which suggest applications of this process in fabricating high-performance devices. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.