Electrical Control of near-Field Energy Transfer between Quantum Dots and Two-Dimensional Semiconductors

Abstract

We investigate near-field energy transfer between chemically synthesized quantum dots (QDs) and two-dimensional semiconductors. We fabricate devices in which electrostatically gated semiconducting monolayer molybdenum disulfide (MoS2) is placed atop a homogeneous self-assembled layer of core-shell CdSSe QDs. We demonstrate efficient nonradiative Förster resonant energy transfer (FRET) from QDs into MoS2 and prove that modest gate-induced variation in the excitonic absorption of MoS2 leads to large (∼500%) changes in the FRET rate. This in turn allows for up to ∼75% electrical modulation of QD photoluminescence intensity. The hybrid QD/MoS2 devices operate within a small voltage range, allow for continuous modification of the QD photoluminescence intensity, and can be used for selective tuning of QDs emitting in the visible-IR range.

Evidence for Fast Interlayer Energy Transfer in MoSe2/WS2 Heterostructures

“…Energy transfer (ET) is a ubiquitous phenomenon commonly observed in molecular complexes, biological systems, and semiconductor heterostructructures [1][2][3][4][5][6] . In a properly designed heterostructure, energy of an excited state travels across hetero-interfaces, resulting in physical responses unique to the system.…”

Temperature-dependent resonance energy transfer from CdSe–ZnS core–shell quantum dots to monolayer MoS2

“…Both the quenched PL and decreased decay time of the QDs in the structures indicate the resonance ET from the QDs to MoS 2 at room temperature. Note that although the emission changes of QDs can be induced by resonance ET or charge transfer from QDs to MoS 2 , charge transfer does not play a role in our experiments because we selected core-shell QDs with strong electron-hole pair confinement and long ligands, in which the charge transfer effect is inefficient or absent [21]. To further exclude the contribution of charge transfer, two additional control experiments were performed.…”

“…S1 in the Electronic Supplementary Material (ESM)). Such an overlap of spectra of the QDs emission and MoS 2 absorption is beneficial for efficient ET from QDs to MoS 2 [20,21]. For later comparison, a sample of the QDs directly deposited on the substrate was also fabricated using the spin-coating method under the same experimental conditions described above.…”

“…These properties have already enabled the applications of MoS 2 in various optoelectronic devices, including photodetectors [8,9], solar convertors [10], and ultrathin light-emitting diodes (LEDs) [11][12][13]. In particular, the prominent excitonic features of MoS 2 during interaction with excited photons offer a promising approach to construct multifunctional, high-performance hybrid structures in which monolayer MoS 2 and zero-dimensional quantum dots (QDs) are coupled efficiently through charge transfer or resonance energy transfer (ET) [14][15][16][17][18][19][20][21]. Specifically, the QDs, serving as a fluorescent donor, transfer the absorbed photon energy to the MoS 2 via nonradiative dipoledipole interaction during the process of resonance ET, which consequently enhances the absorptive properties of MoS 2 , yielding tunable photoluminescence in lightemitting devices, more efficient solar cells, and sensitive photodetectors [18][19][20][21].…”

Emerging opportunities in the two-dimensional chalcogenide systems and architecture

“…Energy transfer from CdSe quantum dots has been used as a local probe to the 2D system dielectric environment, showing reduced dielectric screening in monolayer MoS 2 [160]. Gating a 2D TMD-QD composite has been used to control the relative band alignment between the QDs and the TMD, such that resonant energy transfer can be used to control the relative PL intensity of the TMD or QDs [161]. These studies provide preliminary insight into the interactions at specific 2D-0D interfaces, with promise for future studies to broaden these fundamental insights (see Figs.…”