Directional self-assembly of organic semi-type core-shell microwires for programmable visible-to-near-infrared waveguiding conversion

Organic topological structures integrating multi-color emission and waveguide for optical interconnects are of considerable significance in both scientific research and optoelectronic applications. However, limited success in organic near-infrared (NIR) emitters and difficult manipulation of intermolecular interactions lead to a severe restriction of the photon waveguide for optical communication. Herein, we have purposefully designed dibenzothiophene-based charge-transfer (CT) cocrystals with tunable NIR emission from 710 to 840 nm via finely increasing their aggregation closeness and CT interaction intensity. The controlled molecular stacking evolution from a loosely to a tightly mixed stack achieved a desired narrowed optical band gap of 1.8 eV. Furthermore, these CT cocrystals with a low optical loss coefficient of 0.077 dB/μm at 840 nm were introduced into NIR-emissive semi-type core-shell heterostructures, which realized effective energy transfer with a high conversion efficiency of 40.5% between visible and NIR emission. This strategy paves the way toward precise processing of photons with transmission wavelengths for integrated optoelectronics.