Design and Fabrication of Lab-on-chip for Fluorescence Detection of Ruthenium Complex

This work presents a lab-on-chip, based on thin film optoelectronic devices, for the on-chip detection of fluorescent ruthenium complex. The fluorescent molecule used in this work is the ruthenium complex [Ru(phen)
₂
(dppz)]
²⁺
, whose absorption and emission peaks are around 450 and 610 nm, respectively. The on-chip fluorescence detection, performed on a single glass substrate, is achieved through the combination of a thin film interferential filter, which rejects the excitation radiation, and amorphous silicon photosensors, which detect the fluorescent light. The photosensors and the filter have been designed taking into account the optical properties of the ruthenium complex. Characterization of the two devices shows that the photosensor responsivity is equal to 275 mA/W at 610 nm, and that the filter reduces the excitation radiation by four orders of magnitude without affecting the transmission of the ruthenium complex fluorescence.