On-chip organic optoelectronic system for fluorescence detection

Conventional fluorescence sensing, despite its high sensitivity, is poorly suited for point-of-need applications due to the bulkiness and cost constraints of standard components. An urgent market demand exists for integrated, portable, and high-performance solutions. Here, an efficient and miniaturized fluorescence sensor is demonstrated by innovative integration on a single substrate of organic optoelectronic devices, such as an organic photodiode and an organic light-emitting diode, with a polymeric distributed Bragg reflector. Optical modeling of the 3D layout of integration of the three all-organic components allows maximizing the optical efficiency of the sensing system, which outperforms that of state-of-the-art miniaturized fluorescence sensors by two orders of magnitude. Accordingly, fluorescence signals from microfluidic volumes of Rhodamine 700 are detected by the sensor over a wide range of dye concentrations, ranging from 10-3 M to 10-6 M. The optimized exploitation of the angular dependence of the distributed Bragg reflector filter characteristics provides a remarkable reduction of the undesired optical signal of excitation. As a result, a significant increase of the signal-to-noise ratio allows for halving the detection limit of Rhodamine 700 down to 9.2 mu M, thus demonstrating the possible implementation of such innovative integrated detection scheme for biodiagnostics.A single and miniaturized fluorescence sensor is obtained by the vertical integration of organic optoelectronic devices and organic photonic components.