An organic photodetector (OPD) comprises a microcavity defined by a reflective electrode and a semi-transparent electrode, wherein the microcavity comprises a transparent conductive oxide layer and an active layer comprising an n-type organic semiconductor and a p-type organic semiconductor, and wherein the blend of the n-type organic semiconductor and the p-type organic semiconductor exhibits low absorption at the resonance wavelength, which results in an excellent optical sensitivity in a favorably narrow wavelength region and allows to tune the response to different wavelengths depending on the desired application. In addition, methods of producing such organic photodetectors and methods of tuning the resonance of a microcavity formed in an organic photodetector (OPD) to a predetermined wavelength are provided.