Recent developments in the structurally integrated OLED-based platform of luminescent chemical and biological sensors
are reviewed. In this platform, an array of OLED pixels, which is structurally integrated with the sensing elements, is
used as the photoluminescence (PL) excitation source. The structural integration is achieved by fabricating the OLED
array and the sensing element on opposite sides of a common glass substrate or on two glass substrates that are attached
back-to-back. As it does not require optical fibers, lens, or mirrors, it results in a uniquely simple, low-cost, and
potentially rugged geometry. The recent developments on this platform include the following:
(1) Enhancing the performance of gas-phase and dissolved oxygen sensors. This is achieved by (a) incorporating high-dielectric
TiO2 nanoparticles in the oxygen-sensitive Pt and Pd octaethylporphyrin (PtOEP and PdOEP, respectively)-
doped polystyrene (PS) sensor films, and (b) embedding the oxygen-sensitive dyes in a matrix of polymer blends such as
(2) Developing sensor arrays for simultaneous detection of multiple serum analytes, including oxygen, glucose, lactate,
and alcohol. The sensing element for each analyte consists of a PtOEP-doped PS oxygen sensor, and a solution
containing the oxidase enzyme specific to the analyte. Each sensing element is coupled to two individually addressable
OLED pixels and a Si photodiode photodetector (PD).
(3) Enhancing the integration of the platform, whereby a PD array is also structurally integrated with the OLED array
and sensing elements. This enhanced integration is achieved by fabricating an array of amorphous or nanocrystalline Si-based
PDs, followed by fabrication of the OLED pixels in the gaps between these Si PDs.