Plasmonic biosensor device comprising a first and second electrode, a charge carrier tunnelling junction for providing charge carriers for generating electroluminescent light emission, that is in electrical connection with the first and second electrodes for application of a voltage potential difference. the second electrode comprises or forms a plasmonic structure including a plurality of optical nanoantennas or a plurality of electrically interconnected optical nanoantennas configured to generate plasmons and light emission via the charge carriers provided by charge carrier tunneling in the charge carrier tunnelling junction. the plurality of optical nanoantennas extend thereon.