A method for transferring an assembly of oriented nanowires from a fluid to a substrate surface, comprising: providing (FIG. 2A) a fluid to a container, said fluid comprising a first liquid (11), a second liquid (12) and a plurality of nanowires (25), wherein the first and second liquids phase separate into a sub phase, a top phase, and an interface (13) between the sub phase and the top phase; wherein the nanowires are functionalized to align vertically into a nanowire aggregate at the interface; wherein the fluid is provided with a substance in a composition configured to change the composition of the top phase or the composition of the sub phase to counteract bulging of the interface (FIG. 2B); and bringing the nanowire aggregate into contact with a substrate surface such that a majority of the nanowires are aligned with respect to each other on the substrate.