Today, almost all solution-processed absorber layers for CIGS thin-film solar cells require a gas-phase selenization step after film deposition. In this contribution, the addition of excess selenium to CIGS precursor inks, either as elemental Se particles or Se2--containing salts, is investigated as an alternative way to induce selenization during thermal annealing. Most importantly, we find that (N2H5)(2)Se is a selenium-containing additive that both stabilizes CuInS2 nanocrystal inks and induces the formation of a pure CuInSe2 phase. (C) 2615 Elsevier B.V. All rights reserved.