A new platform for luminescent chemical and biological sensors, integrating the excitation source, an OLED, with the sensing component, is described. The utility of the platform is demonstrated for an oxygen sensor and its potential is demonstrated for antibody-antigen immunoassays. The oxygen sensor is operable in two modes, i.e., photoluminescence (PL) intensity mode and lifetime mode, where changes in the PL intensity and lifetime, respectively, are correlated with the oxygen level. In the lifetime mode, the need for sensor calibration, which remains a challenge in real-world sensing applications, is eliminated. Attributes and issues related to sensor performance, including design and stability, are discussed.