Novel solution-processable light filter approaches for light detection purpose in Lab-on-Chip-Systems

Abstract

In this contribution, two approaches of the solution processing of novel spectral light filters are demonstrated. The first approach shows the combination of light filtering capability with electrical conductivity in a “light filter electrode” by mixing colorants into poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) ink. Different colorants are investigated concerning their influence on the workfunction and the electrical conductivity of the resulting PEDOT:PSS layers. In addition, these electrodes could be integrated into organic photodiodes, opening up the possibility of using the whole device for specific light detection. Within the second approach, the surface plasmon resonance and the scattering of metal nanoparticles is used for light filtering. Light scattering (and therefore the reflection of excitation light back into the microfluidic channel) increases the excitation efficiency, thus increasing the intensity of the fluorescent light. With this approach, the sensitivity of the demonstrated light detectors can effectively be increased while simultaneously decreasing the detection limit of the substance of interest.