In-Plane Aligned Colloidal Quantum Wells via Electrophoretic Deposition for Directional Emission

Directional emission is highly desirable for a wide range of photonic and optoelectronic applications, such as displays, lasers, and optical communications. II–VI Colloidal quantum wells (CQWs, or nanoplatelets), owing to their anisotropic shape and strong quantum confinement, inherently support directional emission when properly aligned. Here, we demonstrate a reliable and convenient electrophoretic deposition method to achieve in-plane alignment of CQWs on substrates. This technique enables controlled placement of CQWs exclusively in electrode-defined regions, offering both spatial selectivity and emission directionality, which provides a scalable and straightforward route for integrating anisotropic quantum well emitters into optoelectronic device architectures.