OLED OPD Matrix for Sensing on a Single Flexible Substrate

Integration of organic light emitting diodes (OLEDs) and organic photodetectors (OPDs) on flexible plastic substrates promises compact and low-cost optical detection units for multiplex sensors. These units may be laminated to a microfluidic system for sensing applications in a liquid. Here, a $6\times 6$ element matrix of alternating blue OLEDs and OPDs is demonstrated on a single flexible plastic substrate. The devices are fabricated by masked thermal evaporation on a $200~\mu \text{m}$ thick polyethylene terephthalate (PET) foil. The individual device size is 1 mm $\times 1$ mm. Both OLEDs and OPDs are demonstrated to work. The spectral characteristics are shown to be suitable for fluorescence measurements. Signals from fluorescence-labeled spots above the OPDs under OLED excitation are investigated. Successful operation of the OLED-OPD matrix for reflection measurement is demonstrated.