Pradeepa, HL and Bid, A and Basu, JK (2020) Strong suppression of emission quenching in core quantum dots coupled to monolayer MoS2. In: Nanoscale Advances, 2 (9). pp. 3858-3864.
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Abstract
Non-radiative processes like energy and charge transfer in 0D-2D semiconductor quantum dot (QD)-transition metal dichalcogenides (TMDs) and other two-dimensional layered materials, like graphene and analogs, leading to strong quenching of the photoluminescence (PL) of the usually highly emissive QDs, have been widely studied. Here we report control of the emission efficiency of core QDs placed in close proximity to the monolayers of MoS2. The QDs are transferred in the form of a high-density compact monolayer with the dot-dot separation, δ as well as the MoS2-QD separation, d, being controlled through chemical methods. While at larger separations we observe some quenching due to non-radiative processes, at smaller separations we observe enhanced emission from QDs on MoS2 as compared to the reference despite the presence of significant non-radiative charge transfer. Interestingly, at small separations δ, we see evidence of strong dot-dot interactions and a significant red shift of QD PL which enhances spectral overlap with the B exciton of MoS2. However, we observe significant reduction of PL quenching of QDs relative to longer δ and d cases, despite increased probability of non-radiative resonant energy transfer to MoS2, due to the enhanced spectral overlap, as well as charge transfer. Significantly we observe that simultaneously the intensity of the B exciton of MoS2 increases significantly suggesting the possibility of coherent and resonant radiative energy exchange between the 0D excitons in QDs and the 2D B exciton in MoS2. Our study reveals interesting nanoscale light-matter interaction effects which can suppress quenching of QDs leading to potential applications of these nanoscale materials in light emitting and photonic devices. This journal is © The Royal Society of Chemistry.
| Item Type: | Journal Article |
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| Publication: | Nanoscale Advances |
| Publisher: | Royal Society of Chemistry |
| Additional Information: | The copyright for this article belongs to The Author(s). |
| Keywords: | Charge transfer; Energy transfer; Excitons; Layered semiconductors; Light emission; Molybdenum compounds; Monolayers; Nanocrystals; Photonic devices; Quenching; Red Shift; Separation; Transition metals, Compact monolayers; Emission efficiencies; Emission quenching; Light-matter interactions; Nano-scale materials; Nonradiative process; Resonant energy transfer; Transition metal dichalcogenides, Semiconductor quantum dots |
| Department/Centre: | Division of Physical & Mathematical Sciences > Physics |
| Date Deposited: | 13 Jan 2023 05:21 |
| Last Modified: | 13 Jan 2023 05:21 |
| URI: | https://eprints.iisc.ac.in/id/eprint/79085 |
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