A film can include a plurality of semiconductor nanocrystals and a J-aggregating material in solution. The film can exhibit 90% energy transfer efficiency from the J-aggregating material to the plurality of semiconductor nanocrystals. The film can exhibit photoluminescence that is enhanced at least 2.5 times over an equivalent film including the plurality of semiconductor nanocrystals alone when excited at 465 nm. The film can be contacted onto a substrate by spin casting.