Two-Color Sensor for Lab-on-Chip Applications

Lab-on-Chip (LoC) devices can integrate onto a small single circuit one or more laboratory functions, reducing consumption of samples and reagents with consequent low pollution and low costs. LoC typically uses electrochemical or optical detection methods for quantifying the analysis. Among the others, optical methods rely on the detection of fluorescence radiation, induced by an excitation light. Nowadays, a filter is commonly used to properly distinguish between the two different lights. To avoid this additional technological step, this paper proposes the use of an amorphous silicon p-i-n photodiode, whose spectral response is modulated by changing the voltage applied across the diode. A simple algorithm allows to extract the two different lights intensities through a straightforward implementation. © 2025 IEEE.