Nanostructured Organic Photodetectors for Differential Measurements

Organic Photodetectors (OPDs) provide significant advantages in sensing technology and are on the rise due to their integrability in a variety of substrates and devices. Recent studies demonstrate their efficient usage in applications such as image sensing, optical communications, and biosensing [1], [2]. It was previously shown that incorporating nanograting structures into OPDs allows for selective absorption enhancements at wavelength regions of interest using the optical resonance effect [3]. In this work we present experiments towards differential sensing of photodetectors with nanostructured, semi-transparent OPDs on a single substrate. Two or more nanostructures with different grating parameters can be fabricated on a single substrate while the layer stack of the photodetector remains the same for all detectors. This leads to wavelength- and grating-dependent photocurrent responses of the OPDs and can be exploited for differential measurements. Exciting all OPDs simultaneously and only considering the differential signal eliminates background noise, excitation light and focuses on the sensitive wavelength regions due to the nanostructures.