Photoconductive optoelectronic devices, such as photodetectors and photovoltaics, are provided. The devices are sensitized to a particular wavelength (or range of wavelengths) of electromagnetic radiation such that the devices provide increased performance efficiency (e.g., external quantum efficiency) at the wavelength. The devices include a photoconductive semiconductor layer spanning an electrode gap between two electrodes to provide a photoconductive electrical conduit. Abutting the semiconductor layer is a plurality of plasmonic nanoparticles. The improved efficiency of the devices results from wavelength-dependent plasmonic enhancement of device photosensitivity by the plasmonic nanoparticles.