Integrated organic electronic based optochemical sensors using polarization filters

Publication from Materials

Kraker Elke, Haase Anja, Lamprecht Bernhard, Jakopic Georg, Konrad Christian, Köstler Stefan

Applied Physics Letters 92(3): 033302. , 2008


A compact, integrated photoluminescence based oxygen and pH sensor, utilizing an organic light
emitting device OLED as the light source and an organic photodiode OPD as the detection unit,
is described. The main challenge in such an integrated sensor is the suppression of the excitation
light at the detector, which is typically by many orders of magnitude higher in intensity than the
emitted fluorescence. In our approach, we refrain from utilizing edge filters which require narrow
band excitation sources and dyes with an adequate large Stokes shift. We rather developed an
integrated sensor concept relying on two polarizers to separate the emission and excitation light.
One polarizer is located right after the OLED, while the other one, oriented at 90° to the first, is
placed in front of the OPD. The main advantage of this solution is that any combination of excitation
and emission light is acceptable, even if the two signals overlap spectrally. This is especially
important for the use of OLEDs as the excitation sources, as these devices typically exhibit a broad
spectral emission.

Keywords: OLED Organic electronics Organic photodiode Sensor Oxygen Sensor pH sensor polarization


Additional informations: Sensor Technology