Vanishing quantum confinement enables bright and thermally excited multi-carrier emission from semiconductor nanocrystals
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arXiv
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| Autores principales: | , , , , , , , |
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| Formato: | Preprint |
| Publicado: |
2025
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| _version_ | 1866909964668239872 |
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| author | Arens, Tjom Vonk, Sander J. W. Vlasblom, A. Willem Samoli, Margarita Vanmaekelbergh, Daniel Geiregat, Pieter Hens, Zeger Rabouw, Freddy T. |
| author_facet | Arens, Tjom Vonk, Sander J. W. Vlasblom, A. Willem Samoli, Margarita Vanmaekelbergh, Daniel Geiregat, Pieter Hens, Zeger Rabouw, Freddy T. |
| contents | Recently, nanocrystals in the regime of vanishing quantum confinement-termed bulk nanocrystals (BNCs)-have demonstrated remarkable optical gain characteristics. While their high-power lasing performance was demonstrated convincingly, the photophysics at low and intermediate powers-where charge-carrier populations are discrete-remain unexplored. Using single-photon avalanche diode (SPAD) array technology, we resolve the dynamics and energetics of six multi-carrier excited states in individual CdSe/CdS core/shell BNCs, containing up to four electrons and two holes. Each state exhibits bimodal emission, indicative of thermal equilibrium between closely spaced electron and hole levels, confirmed via temperature-dependent single-particle measurements. Quantification of radiative and nonradiative decay channels reveals strongly suppressed Auger recombination through both the negative- and positive-trion pathways. We present a model that combines statistical scaling of rate constants with Fermi-Dirac thermal occupations of electron and hole levels, bridging the transitional regime between quantum-confined and bulk nanocrystals, and providing a comprehensive framework for understanding this emerging class of materials. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_13867 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Vanishing quantum confinement enables bright and thermally excited multi-carrier emission from semiconductor nanocrystals Arens, Tjom Vonk, Sander J. W. Vlasblom, A. Willem Samoli, Margarita Vanmaekelbergh, Daniel Geiregat, Pieter Hens, Zeger Rabouw, Freddy T. Materials Science Recently, nanocrystals in the regime of vanishing quantum confinement-termed bulk nanocrystals (BNCs)-have demonstrated remarkable optical gain characteristics. While their high-power lasing performance was demonstrated convincingly, the photophysics at low and intermediate powers-where charge-carrier populations are discrete-remain unexplored. Using single-photon avalanche diode (SPAD) array technology, we resolve the dynamics and energetics of six multi-carrier excited states in individual CdSe/CdS core/shell BNCs, containing up to four electrons and two holes. Each state exhibits bimodal emission, indicative of thermal equilibrium between closely spaced electron and hole levels, confirmed via temperature-dependent single-particle measurements. Quantification of radiative and nonradiative decay channels reveals strongly suppressed Auger recombination through both the negative- and positive-trion pathways. We present a model that combines statistical scaling of rate constants with Fermi-Dirac thermal occupations of electron and hole levels, bridging the transitional regime between quantum-confined and bulk nanocrystals, and providing a comprehensive framework for understanding this emerging class of materials. |
| title | Vanishing quantum confinement enables bright and thermally excited multi-carrier emission from semiconductor nanocrystals |
| topic | Materials Science |
| url | https://arxiv.org/abs/2512.13867 |