Surface plasmon resonance sensor based on a planar polychromatic OLED light source

We present a novel surface plasmon resonance (SPR) sensor based on an integrated planar and polychromatic light source. The sensor comprises an organic light emitting diode (OLED) and a metallic sensing layer located on opposite sides of a glass prism. We successfully fabricated and tested prototype sensors based on this approach by the use of different prism geometries and OLEDs with blue, green and red emission color. We investigated the angular and wavelength dependent SPR dispersion relation for sensing layers consisting of silver and gold of different thicknesses in contact with air. Further on we demonstrated the sensor function by real time monitoring of temperature changes inside an adjacent water reservoir as well as by recording the dissolving process of sodium chloride in water. This shows that the configuration can in principle be used for bio-sensing applications. The presented technique offers the advantage that there is no necessity to couple light from external bulky sources such as lasers or halogen lamps into the sensing device which makes it particularly interesting for miniaturization. The presented SPR configuration can be monolithically integrated oil one common substrate. Furthermore it is compatible with the planar glass light pipe platform for SPR sensing and the two-color approach for the determination of the thickness and the dielectric constant of thin films in a single experiment.