Polymer light-emitting devices based on the in situ formation of a p-i-n junction in a polymer blend have been fabricated by roll lamination. Single-walled carbon nanotubes are used as both the anode and cathode for a fabrication process that does not employ vacuum. The metal-free, thin-film devices exhibit a low turn-on voltage, modestly high efficiency, and brightness. The devices are fairly transparent and exhibit high mechanical flexibility. No failure was observed after repeated bending to a 2.5 mm radius and unbending for 50 cycles. Tandem light-emitting devices were prepared, by stacking a blue device on top of a yellow device, for the convenient generation of various mixed colors.