Research progress of single quantum-dot spectroscopy and exciton dynamics

Abstract

Colloidal semiconductor quantum dots (QDs) have strong light absorption, continuously adjustable narrowband emission, and high photoluminescence quantum yields, thereby making them promising materials for light-emitting diodes, solar cells, detectors, and lasers. Single-QD photoluminescence spectroscopy can remove the ensemble average to reveal the structure information and exciton dynamics of QD materials at a single-particle level. The study of single-QD spectroscopy can provide guidelines for rationally designing the QDs and giving the mechanism basis for QD-based applications. We can also carry out the research of the interaction between light and single QDs on a nanoscale, and prepare QD-based single-photon sources and entangled photon sources. Here, we review the recent research progress of single-QD photoluminescence spectroscopy and exciton dynamics, mainly including photoluminescence blinking dynamics, and exciton and multi-exciton dynamics of single colloidal CdSe-based QDs and perovskite QDs. Finally, we briefly discuss the possible future development trends of single-QD spectroscopy and exciton dynamics.

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

“…22 Using single-dot spectroscopy to study the energy transfer and charge transfer dynamics in 2D/0D heterostructures can remove the ensemble averaging effect and obtain the structure and dynamics information of nanomaterials at the level of single particles. 23,24 However, the current problem is that the PL intensity of single QDs is much smaller than that of 2D-TMDs, and the emission spectra of 2D-TMDs overlap with those of most kinds of QDs, especially for CdSe-based QDs. 9,19 Therefore, how to separate the photons emitted by single QDs and 2D-TMDs is still a key problem.…”

Conversion of Photoluminescence Blinking Types in Single Colloidal Quantum Dots

“…[14,19,22] From the FLID maps, all the two types of blinking could be observed in CdSe-based QDs and perovskite QDs. [5,12,14,15,[22][23][24][25][26][27][28][29][30][31] Furthermore, two different blinking types could coexist in CdSe-based QDs and perovskite QDs. [14,[32][33][34] The rich variety in the reported observations raises some fundamental questions: why do the QDs with the same chemical compositions and from the same production batch exhibit distinct blinking types?…”