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DOE OSTI · 3017642

Bound Exciton Complexes in Near-Infrared Emitting Quantum Shells

Harankahage, Dulanjan [The Center for Photochemical Sciences, Bowling Green, OH (United States); Bowling Green State University, OH (United States)]·Nazar, Divesh [The Center for Photochemical Sciences, Bowling Green, OH (United States); Bowling Green State University, OH (United States)] (ORCID:0009000902466174)·Molkens, Korneel [Ghent University, Gent (Belgium)]·Bondarchuk, Mykhailo V. [The Center for Photochemical Sciences, Bowling Green, OH (United States); Bowling Green State University, OH (United States)]·Hicks, Christopher M. [The Center for Photochemical Sciences, Bowling Green, OH (United States); Bowling Green State University, OH (United States)] (ORCID:0009000963089739)·Marder, Andrew A. [The University of Texas at Dallas, Richardson, TX (United States)] (ORCID:0000000289819762)·Montemurri, Michael [Bowling Green State University, OH (United States)]·Roach, Adam [The Center for Photochemical Sciences, Bowling Green, OH (United States); Bowling Green State University, OH (United States)]·Tanghe, Ivo [Ghent University, Gent (Belgium)] (ORCID:0000000192415585)·Sun, Liangfeng [The Center for Photochemical Sciences, Bowling Green, OH (United States); Bowling Green State University, OH (United States)] (ORCID:0000000305271777)·Schaller, Richard D. [Argonne National Laboratory (ANL), Argonne, IL (United States); Northwestern University, Evanston, IL (United States)] (ORCID:0000000196968830)·Diroll, Benjamin T. [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000334880213)·Malko, Anton V. [The University of Texas at Dallas, Richardson, TX (United States)] (ORCID:0000000164107112)·Tarnovsky, Alexander N. [The Center for Photochemical Sciences, Bowling Green, OH (United States); Bowling Green State University, OH (United States)] (ORCID:0000000179182676)·van Thourhout, Dries [Ghent University, Gent (Belgium)] (ORCID:000000030111431X)·Hens, Zeger [Ghent University, Gent (Belgium)] (ORCID:0000000270413375)·Geiregat, Pieter [Ghent University, Gent (Belgium)] (ORCID:0000000172178738)·Zamkov, Mikhail [The Center for Photochemical Sciences, Bowling Green, OH (United States); Bowling Green State University, OH (United States)] (ORCID:0000000286382972)
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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 singleexciton gain.

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Harankahage, Dulanjan [The Center for Photochemical Sciences, Bowling Green, OH (United States); Bowling Green State University, OH (United States)], Nazar, Divesh [The Center for Photochemical Sciences, Bowling Green, OH (United States); Bowling Green State University, OH (United States)] (ORCID:0009000902466174), Molkens, Korneel [Ghent University, Gent (Belgium)], Bondarchuk, Mykhailo V. [The Center for Photochemical Sciences, Bowling Green, OH (United States); Bowling Green State University, OH (United States)], Hicks, Christopher M. [The Center for Photochemical Sciences, Bowling Green, OH (United States); Bowling Green State University, OH (United States)] (ORCID:0009000963089739), Marder, Andrew A. [The University of Texas at Dallas, Richardson, TX (United States)] (ORCID:0000000289819762), Montemurri, Michael [Bowling Green State University, OH (United States)], Roach, Adam [The Center for Photochemical Sciences, Bowling Green, OH (United States); Bowling Green State University, OH (United States)], Tanghe, Ivo [Ghent University, Gent (Belgium)] (ORCID:0000000192415585), Sun, Liangfeng [The Center for Photochemical Sciences, Bowling Green, OH (United States); Bowling Green State University, OH (United States)] (ORCID:0000000305271777), Schaller, Richard D. [Argonne National Laboratory (ANL), Argonne, IL (United States); Northwestern University, Evanston, IL (United States)] (ORCID:0000000196968830), Diroll, Benjamin T. [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000334880213), Malko, Anton V. [The University of Texas at Dallas, Richardson, TX (United States)] (ORCID:0000000164107112), Tarnovsky, Alexander N. [The Center for Photochemical Sciences, Bowling Green, OH (United States); Bowling Green State University, OH (United States)] (ORCID:0000000179182676), van Thourhout, Dries [Ghent University, Gent (Belgium)] (ORCID:000000030111431X), Hens, Zeger [Ghent University, Gent (Belgium)] (ORCID:0000000270413375), Geiregat, Pieter [Ghent University, Gent (Belgium)] (ORCID:0000000172178738), Zamkov, Mikhail [The Center for Photochemical Sciences, Bowling Green, OH (United States); Bowling Green State University, OH (United States)] (ORCID:0000000286382972). 2026-01-15. Bound Exciton Complexes in Near-Infrared Emitting Quantum Shells. https://doi.org/10.1021/acsnano.5c18640

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