Electrical excitation of microcavity polaritons by radiative pumping from a weakly coupled organic semiconductor

In an organic semiconductor, the population of microcavity polariton states occurs via an uncoupled exciton reservoir. Consequently, this results in the inefficient excitation of the upper polariton branch, and a significant population of uncoupled excitons in the active material. Here, an alternate excitation approach is demonstrated that permits the direct population of microcavity polariton states under both electrical and optical excitation without first forming an exciton reservoir. This is realized by introducing a weakly coupled emitter into an optical microcavity containing an organic semiconductor suitable for strong exciton-photon coupling. In contrast to previous work on microcavity polariton luminescence in organic semiconductors, angle-resolved measurements of the photoluminescence and electroluminescence show variations in upper and lower branch emission intensity consistent with the branch photon character. These results confirm that the excitation of the microcavity polariton states is by radiative pumping from the weakly coupled emitter.