Year: 2026
Type: article
Abstract: Near-infrared (NIR) light sources based on colloidal semiconductor nanocrystals (NCs) represent a scalable, low-cost alternative to epitaxial semiconductor platforms. However, their performance remains hindered by rapid Auger recombination, a problem that is particularly pronounced in narrow-bandgap materials. Here, we report on CdS/HgS/CdS and CdS/HgCdSe/ZnS quantum shells (QSs), a class of spherical quantum wells specifically engineered for a suppression of nonradiative Auger processes. Fabricated QSs exhibit tunable NIR emission with photoluminescence quantum yields reaching ∼60% below 1000 nm and up to 30% near 1300 nm. Optical gain and stimulated emission were observed in CdS/HgS/CdS QSs. In contrast, CdS/HgCdSe/ZnS QSs displayed a photoinduced absorption in lieu of optical gain despite demonstrating a comparatively stronger Auger suppression. Transient absorption spectroscopy revealed that this phenomenon arises from the formation of bound multiexciton complexes that induce long-lived sub-bandgap multiexciton states. The observation of such bound excitonic clusters at room temperature offers a pathway toward nonlinear NIR photonic phenomena, including biexciton-exciton cascade emission, optical modulation, and single-exciton gain.
Source: ACS Nano
Authors: Dulanjan Harankahage, Divesh Nazar, Korneel Molkens, Mykhailo V. Bondarchuk, Christopher M. Hicks, Andrew A. Marder, Michael Montemurri, Adam Roach, Ivo Tanghe, Liangfeng Sun, Richard D. Schaller, Benjamin T. Diroll, Anton V. Malko, Alexander N. Tarnovsky, Dries van Thourhout, Zeger Hens, Pieter Geiregat, Mikhail Zamkov
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Awards: Collaborative Research: Single Photon Emission in Lanthanide-Doped 2D Materials & Devices, G2407447897, Electrically Driven Quantum Dot Lasers, a Fundamental Nanomaterials/Nanophotonics Approach (E-QUAL), G4198010607, MRI: Acquisition of a Laser Amplification System for Sensitive, High-Resolution, Multi-Time Scale Spectroscopy, G4816602320, MRI: Acquistion of Equipment Enhancing the Ultrafast Spectroscopy Capabilities of the Center for Photochemical Sciences at BGSU, Solution-processed electrically-pumped laser diodes utilizing colloidal quantum shells, HITEC - High Temperature Exciton Condensation in 2D Colloidal Nanoplatelets, Understanding Emission, Absorption and Energy Transfer Involving Classical and Quantum Light Interacting with Molecules, G6910236118
OpenAlex ID: W7124463339