Here we present a ligand exchange of long insulating molecules with short, robust and environmentally friendly iodide ions via a mild flocculation of PbSe nanocrystals (NCs). This ligand exchange leads to the formation of stable colloidal solutions in various polar solvents and in a broad concentration range via electrostatic repulsion. The iodide capping ligands preserve the electronic structure and maintain the optical properties of the PbSe NCs, both in solution and in the form of solid films. The spin-coated PbSe NC solids exhibit good transport characteristics with electron mobilities in the linear and saturation regimes reaching (2.1±0.3) cm2/(V∙s) and (2.9±0.4) cm2/(V∙s), respectively. This opens up opportunities for the low-cost and low-temperature fabrication of NC thin-films being attractive for applications in the fields of electronics and optoelectronics.