Highly Effective Multiple-Patterned Plasmonic Nanostructures for Flexible Organic Photodetectors

Abstract

Introducing plasmonic structures is a viable way to enhance the performance of optoelectronic devices by improving surface plasmon couplings. In this study, we combined block-copolymer lithography and nano-imprinting lithography to fabricate metal electrodes with highly effective multiple-patterned plasmonic nanostructures. The metal electrodes were then used as back reflectors in organic photodiodes (OPDs). The multiple-patterned electrodes exhibited increased light absorption compared to conventional flat electrodes, increasing the light responsivity of OPDs from 0.82 AW-1 to 5.91 AW-1 under 532-nm-wavelength light illumination at an intensity of 20 µW cm-2. Theoretical study and near-field scanning optical microscopy revealed strong surface plasmon coupling of these nanostructured electrodes. Moreover, the multiple-patterned OPDs fabricated on a plastic substrate showed highly stable device performance. Furthermore, flexible 8×8 photosensor arrays were successfully fabricated and used for detecting incident photonic signals with high resolution. These results demonstrate that the developed multiple patterns provide a versatile and effective route for developing high-performance organic optoelectronic devices.