A light source comprises an organic light-emitting device, which emits radiation having a first spectrum, and a phosphor layer, which absorbs a portion of the light emitted by the organic light-emitting layer and which emits light having a second spectrum. The organic light-emitting device comprises an organic light-emitting layer disposed between a pair of electrodes, and at least a charge-blocking layer disposed between the organic light-emitting layer and one of the electrodes. The phosphor layer typically absorbs less than all of the light emitted by the organic light-emitting layer and typically covers the entire organic light-emitting device. The light emitted by the organic light-emitting layer is mixed with the light emitted by the phosphor layer to produce light having a third spectrum.