Heterogeneous Integration of Single-Crystalline Organic Semiconductor Microstructures via Capillary Condensation.

Abstract

Single-crystalline organic emissive semiconductors, featuring high photoluminescence quantum efficiency, intrinsic optical microcavities, and high charge carrier mobility, hold great promise for integrated photonics applications. However, realizing practical integrated photonics requires the deterministic patterning of multicomponent single-crystalline organic semiconductors with high resolution and unidirectional crystallographic orientation, which remains an ongoing challenge. Here, we report a nanoconfined recrystallization strategy that enables the integrated patterning of multicomponent, single-crystalline organic microstructures. By precisely regulating site-specific capillary condensation within top-pillar-confined spaces, we achieve selective rewetting of printed polycrystalline semiconductors, leading to the formation of discrete multicomponent nanoconfined liquid bridges without cross-contamination. Controlled nucleation and directional growth under regulated evaporation conditions yielded well-defined single-crystalline microstructures with a uniform size and pure crystallographic orientation. These multicomponent heterogeneous microstructures achieve a minimum feature size and interfeature spacing of 2 μm, representing a significant advancement over conventional patterning methods. These high crystalline structures demonstrate excellent optical microcavity characteristics, achieving an ultralow lasing threshold of 0.49 μJ cm-2 and quality factor (Q) as high as 1.1 × 104. Leveraging this platform, we fabricated 2 in. full-color organic single-crystalline microlaser arrays with pixel densities exceeding 2000 PPI (pixels per inch) and a color gamut coverage of 104% of the Rec. 2020.