The present invention relates to the emission of light which occurs in proportion with an electrical signal, an optical signal, or the combination of both. The emission of light may occur due to the passage of current through a light-emitting polymer, or due to energy transfer of excitons from this polymer to light-emitting quantum dots. Optical sensitivity is achieved through the inclusion of another species of quantum dots whose absorption is generally at longer wavelengths relative to the light-emitting material. Light incident upon the device results in an enhanced current flow in the presence of an applied bias, and thus enhanced excitation of the light-emitting moity is achieved in proportion with the optical power absorbed by the light-absorbing moity. Two device architectures are presented, one based on a mutilayer structure in which the functions of light absorption and light emission are separated, and the other in which these functions are integrated within a single active region.