Thickness-Tunable Self-Assembled Colloidal Nanoplatelet Films Enable Ultrathin Optical Gain Media

• DOI: 10.1021/acs.nanolett.0c02153
• Publication Date: 2020-07-31T15:22:13Z
• Authors: Onur Erdem; Sina Foroutan; Negar Gheshlaghi; Burak Guzelturk; Yemliha Altintas; Hilmi Volkan Demir
• Keywords: Planar waveguides; planar waveguides; liquid interface self-assembly; Science::Physics::Optics and light; Optical gain; 02 engineering and technology; 540; colloidal nanoplatelets; Liquid interface self-assembly; 620; amplified spontaneous emission; Liquid Interface Self-assembly; Colloidal Nanoplatelets; Colloidal nanoplatelets; Amplified spontaneous emission; :Physics::Optics and light [Science]; 0210 nano-technology; optical gain

We propose and demonstrate construction of highly uniform, multilayered superstructures CdSe/CdZnS core/shell colloidal nanoplatelets (NPLs) using liquid interface self-assembly. These NPLs are sequentially deposited onto a solid substrate into slabs having monolayer-precise thickness across tens cm2 areas. Because near-unity surface coverage excellent uniformity, amplified spontaneous emission (ASE) is observed from an uncharacteristically thin film 6 NPL layers, corresponding to mere 42 nm thickness. Furthermore, systematic studies on optical gain these thicknesses ranging 15 layers revealed the gradual reduction in threshold with increasing number along continuous spectral shift ASE peak (∼18 nm). observations can be explained by change mode confinement factor waveguide propagation wavelength. This bottom-up technique for thickness-tunable, three-dimensional used large-area device fabrication.