Hierarchical Thornbush-like Organic Nanostructures via Surface Grafting for High-Performance Multi-level Photomemory Devices

Abstract

Developing multicomponent organic microwire (MW) systems often faces the challenge of performance deterioration at pn junctions. Herein, we report a hierarchical multicomponent system featuring thornbush-like nanostructures composed of p-type porphyrin (TCPP) and n-type perylene diimide (BPE-PTCDI) MWs, fabricated via a facile surface-grafting method. This unique 3D branched architecture maximizes light absorption across the entire visible spectrum by leveraging the complementary optical properties of both components and the light-trapping effect of the thornbush-like structure. Notably, the optimized heterostructure overcomes typical p-n junction drawbacks, maintaining high n-type charge transport characteristics (average μ_e = 0.33 cm ² V^-1s^-1 ) while exhibiting a 100-fold increase in electron mobility under light-soaking conditions, driven by the photo-assisted catalytic properties of TCPP. When integrated into organic field-effect transistors and phototransistors, these nanostructures demonstrate outstanding photoresponsivity and stability. Furthermore, the excellent charge-trapping capability of the TCPP/BPE-PTCDI interface enables multi-level programmable non-volatile photomemory behavior with a large memory window. This work provides a powerful strategy for structural optimization in organic multicomponent systems, expanding their potential for high-density, multifunctional optoelectronic applications.