![]() ![]() ![]() This feature makes this method attractive for the purpose of increasing the luminescence characteristics and outcoupling efficiency for lowering the lasing thresholds. The SA method, on the other hand, makes it possible to create the films monolayer by monolayer with high precision of film thickness with much lower roughness. In this regard, films made of NPLs separated by ligands should also possess critically reduced heat transport, which may then prove to be a promising tool for fabrication of light-emitting devices and lasers using the DLW approach. 15,16 The key to the success of direct writing is preventing the overheating of the remaining material surrounding the ablated regions. As an alternative simple but versatile technique to define possibly a wide range of optical cavities, direct laser writing (DLW) approach was successfully used for nanopatterning of light-emitting materials with relatively low thermal conductivity. Multi-step lithography approach was also previously used for creating self-resonant microlasers made of colloidal NPLs, 14 where the reported lasing threshold was around 21 μJ/cm 2. Also, the 1-xZn xS alloy shell NPLs film was created around a coreless fiber to construct a ring resonator with whispering gallery modes, 13 providing a lasing threshold around 188 μJ/cm 2 and a net modal gain coefficient of 485 cm −1. Recently, a low lasing threshold of 44.5 μJ/cm 2, 12 has been demonstrated in an array of TiO 2 nanocylinders supporting Mie-resonant bound-states-in-the-continuum and coated on top with a layer of CdSe/CdZnS NPLs. In particular, meticulously designed lithographic nanostructures supporting high quality-factor (Q-factor) optical modes can be integrated with light-emitting materials, including NPLs. Cavity architectures are extremely diverse and include Fabry–Perot 8 and whispering-gallery-mode resonators, 9 Mie resonators, 10 bound-states-in-the-continuum, 11 and various other planar designs. However, another prerequisite on route toward lasing is an optical cavity with positive optical feedback. These unique properties make NPLs an extremely promising platform for next-generation lasers. The proposed approach holds great potential for LEDs with improved outcoupling and for distributed feedback lasers or lasers based on bound states in the continuum with directly written optical cavities. In these nanostructured NPL films, fabricated according to the design, we observe photoluminescence enhancement and directional outcoupling effects. Using theoretical calculations, we design the period of the structures to achieve high quality-factor optical modes in the emission band of NPLs. In this work, we show direct laser writing on thin films assembled from CdSe/CdZnS NPLs using either spin-coating or the self-assembly method for the purpose of fabricating. However, the high throughput and reproducible methods for nanopatterning of such films for advanced light-emitting applications are still missing. Moreover, they can be self-assembled into high-quality thin films by simple methods of deposition. Core/shell CdSe/CdZnS nanoplatelets (NPLs) are a promising class of nanomaterials for lasing applications owing to their low thresholds and high stability of stimulated emission generation as compared with many other types of colloids. ![]()
0 Comments
Leave a Reply. |