Erdem, OnurForoutan, SinaGheshlaghi, NegarGuzelturk, BurakAltintas, YemlihaDemir, Hilmi Volkan2021-01-262021-01-2620201530-69921530-6984PubMed ID: 32787166https://doi.org/10.1021/acs.nanolett.0c02153https://hdl.handle.net/20.500.12573/495The authors acknowledge the financial support from the Singapore National Research Foundation under the program NRF-NRFI2016-08 and in part from TUBITAK 115E679. The authors thank Mr. Mustafa Guler for TEM imaging of the as synthesized NPLs and preparation of the TEM cross-sectional sample, Mr. Semih Bozkurt for his support on the AFM characterization, Dr. Gokce Celik for her help on the ellipsometric analyses and confocal microscopy imaging, Mr. Emre Unal for his assistance in photography of the large -area sample, Mr. Mete Duman for his assistance on the recording of the supplementary video, and Dr. Kivanc Gungor for fruitful discussions. O.E. acknowledges TUBITAK for the financial support through BIDEB 2211 program. H.V.D. gratefully acknowledges support from TUBAWe propose and demonstrate construction of highly uniform, multilayered superstructures of 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 of cm(2) areas. Because of near-unity surface coverage and excellent uniformity, amplified spontaneous emission (ASE) is observed from an uncharacteristically thin film having 6 NPL layers, corresponding to a mere 42 nm thickness. Furthermore, systematic studies on optical gain of these NPL superstructures having thicknesses ranging from 6 to 15 layers revealed the gradual reduction in gain threshold with increasing number of layers, along with a continuous spectral shift of the ASE peak (similar to 18 nm). These observations can be explained by the change in the optical mode confinement factor with the NPL waveguide thickness and propagation wavelength. This bottom-up construction technique for thickness-tunable, three-dimensional NPL superstructures can be used for large-area device fabrication.Singapore National Research Foundation NRF-NRFI2016-08 Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) 115E679 2211 Turkish Academy of Sciencesenginfo:eu-repo/semantics/openAccessamplified spontaneous emissionoptical gainplanar waveguidescolloidal nanoplateletsliquid interface self-assemblyarticleVolume: 209 Pages64596465