Combining the benefits of NIR-signals for biosensing with sensitive Si-based detectors

In the context of biomedical applications, optical signals in the near infrared (NIR) region are superior than those in the visible range. Because of reduced absorption and scattering, as well as minimized autofluorescence, signal-to-noise ratios are high and interfering background is low. Carbon nanotubes (CNT) serving as optical biosensors exhibit NIR-fluorescence depending on analyte interaction. The emission peaks of CNTs with (6,4)- and (6,5)-chirality fall exactly on the edge, where the sensitivity of Si-detectors ends and the sensitivity of InGaAs-detectors begins. Due to the several advantages of silicon detectors, like low noise and low-cost, it is of interest to evaluate them for CNTs emitting between 900-1000 nm.