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