Direct Imprinting of Quasi-3D Nanophotonic Structures into Colloidal Quantum-Dot Devices

Three-dimensional (3D) subwavelength nanostructures have emerged and triggered tremendous excitement because of their advantages over the two-dimensional (2D) counterparts in fields of plasmonics, photonic crystals, and metamaterials. However, the fabrication and integration of 3D nanophotonic structures with colloidal quantum dots (CQDs) faces several technological obstacles, as conventional lithographic and etching techniques may affect the surface chemistry of colloidal nanomaterials. Here, the direct fabrication of functional quasi-3D nanophotonic structures into CQD films is demonstrated by one-step imprinting with well-controlled precision in both vertical and lateral directions. To showcase the potential of this technique, diffraction gratings, bilayer wire-grid polarizers, and resonant metal mesh long-pass filters are imprinted on CQD films without degrading the optical and electrical properties of CQD. Furthermore, a dual-diode CQD detector into an unprecedented mid-wave infrared two-channel polarization detector is functionalized by embedding an imprinted bilayer wire-grid polarizer within the CQDs. The results show that this approach offers a feasible pathway to combine quasi-3D nanostructures with colloidal materials-based optoelectronics and access a new level of light manipulation.