Supramolecular engineering of charge transfer in wide bandgap organic semiconductors with enhanced visible-to-NIR photoresponse

Organic photodetectors displaying efficient photoelectric response in the near-infrared are typically based on narrow bandgap active materials. Unfortunately, the latter require complex molecular design to ensure sufficient light absorption in the near-infrared region. Here, we show a method combining an unconventional device architecture and ad-hoc supramolecular self-assembly to trigger the emergence of opto-electronic properties yielding to remarkably high near-infrared response using a wide bandgap material as active component. Our optimized vertical phototransistors comprising a network of supramolecular nanowires of N,N-dioctyl-3,4,9,10-perylenedicarboximide sandwiched between a monolayer graphene bottom-contact and Au nanomesh scaffold top-electrode exhibit ultrasensitive light response to monochromatic light from visible to near-infrared range, with photoresponsivity of 2x10(5) A/W and 1x10(2) A/W, at 570nm and 940nm, respectively, hence outperforming devices based on narrow bandgap materials. Moreover, these devices also operate as highly sensitive photoplethysmography tool for health monitoring. Despite advances in designed supramolecular organic nanowires for optoelectronics, realizing near infrared phototransistors with wide bandgap materials remains a challenge. Here, the authors report high-performance vertical phototransistors featuring supramolecularly engineered organic nanowires.

Automated summary

This study demonstrates the successful creation of efficient organic photodetectors with high near-infrared photoelectric response using unconventional device architecture and ad-hoc supramolecular self-assembly. The optimized devices show ultrasensitive light response with wide bandgap material, outperforming those based on narrow bandgap materials.