Organic Bilayer Heterostructures with Built-in Exciton Conversion for 2D Photonic Encryption.

Organic multilayer heterostructures with accurate spatial organization demonstrate strong light-matter interaction from excitonic responses and efficient carrier transfer across heterojunction interfaces, which are considered as promising candidates towards advanced optoelectronics. However, the precise regulation of the heterojunction surface area for finely adjusting exciton conversion and energy transfer is still formidable. Herein, we designed and synthesized organic bilayer heterostructures (OBHs) with controlled face-to-face heterojunction via a stepwise seeded growth strategy, which is favorable for efficient exciton propagation and conversion of optical interconnects. Notably, the relative position and overlap length ratio of component microwires (L DSA /L BPEA = 0.39∼1.15) in OBHs were accurately regulated by modulating the crystallization time of seeded crystals, resulting into a tailored heterojunction surface area (R = L overlap /L BPEA = 37.6%∼65.3%). These as-prepared OBHs present the excitation position-dependent waveguide behaviors for optical outcoupling characteristics with tunable emission colors and intensities, which were applied into two-dimensional (2D) photonic barcodes. Our strategy opens a versatile avenue to purposely design OBHs with tailored heterojunctions for efficient energy transfer and exciton conversion, facilitating the application possibilities of advanced integrated optoelectronics. This article is protected by copyright. All rights reserved.