A device including an emissive material comprising quantum dots is disclosed. In one embodiment, the device includes a first electrode and a second electrode, a layer comprising quantum dots disposed between the first electrode and the second electrodes, and a first interfacial layer disposed at the interface between a surface of the layer comprising quantum dots and a first layer in the device. In certain embodiments, a second interfacial layer is optionally further disposed on the surface of the layer comprising quantum dots opposite to the first interfacial layer. In certain embodiments, a device comprises a light-emitting device. Other light emitting devices and methods are disclosed.