Charge and energy transfer dynamics in single colloidal quantum dots/monolayer MoS₂ heterostructures

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Colloidal quantum dots (QDs) and monolayer molybdenum disulfide (MoS2) are crucial 0D and 2D materials, respectively.
• Hybrid 0D-2D heterostructures offer unique optoelectronic properties due to interfacial charge and energy transfer.
• Understanding these dynamics is key for advancing optoelectronic device applications.

Purpose of the Study:

• To investigate charge and energy transfer dynamics in colloidal CdSeTe/ZnS quantum dots (QDs)/monolayer molybdenum disulfide (MoS2) heterostructures.
• To quantify the impact of MoS2 on QD exciton generation, recombination, and photoluminescence (PL).
• To elucidate the mechanisms governing exciton dynamics at the single-dot level in these hybrid systems.

Main Methods:

• Utilized time-resolved single-dot photoluminescence (PL) spectroscopy to study QD/MoS2 heterostructures.
• Employed a time-gated method to spectrally resolve PL signals from individual QDs and monolayer MoS2, overcoming spectral overlap.
• Analyzed exciton generation, PL quantum yield, and charge transfer rates.

Main Results:

• Energy transfer from MoS2 to QDs enhanced QD exciton generation by 37.5%.
• Energy transfer from QDs to MoS2 decreased QD PL quantum yield by 66.9%.
• MoS2 increased the discharging rate of QDs by 59% while charging rate remained unchanged.

Conclusions:

• The study provides critical insights into exciton generation and recombination at 0D-2D hybrid interfaces.
• Observed energy transfer effects significantly influence QD optoelectronic properties.
• Findings promote the development and application of QD/MoS2 hybrid systems in advanced optoelectronic devices.