Exciton-Photon Interactions in Semiconductor Nanocrystals: Radiative Transitions, Non-Radiative Processes and Environment Effects

Abstract

In this review, we discuss several fundamental processes taking place in semiconductor nanocrystals (quantum dots (QDs)) when their electron subsystem interacts with electromagnetic (EM) radiation. The physical phenomena of light emission and EM energy transfer from a QD exciton to other electronic systems such as neighbouring nanocrystals and polarisable 3D (semi-infinite dielectric or metal) and 2D (graphene) materials are considered. In particular, emission decay and FRET rates near a plane interface between two dielectrics or a dielectric and a metal are discussed and their dependence upon relevant parameters is demonstrated. The cases of direct (II–VI) and indirect (silicon) band gap semiconductors are compared. We cover the relevant non-radiative mechanisms such as the Auger process, electron capture on dangling bonds and interaction with phonons. Some further effects, such as multiple exciton generation, are also discussed. The emphasis is on explaining the underlying physics and illustrating it with calculated and experimental results in a comprehensive, tutorial manner.

Statistical Analysis of Photoluminescence Decay Kinetics in Quantum Dot Ensembles: Effects of Inorganic Shell Composition and Environment

“…The relaxation processes that shape the decay of excitons in quantum dots (QDs), specifically in systems of packed QDs and in hybrid systems, are one of the critical processes that determine the suitability of these materials for a potential application. − Therefore, discerning the kinetics of photoluminescence (PL) decay of QDs in these systems is of crucial importance for their characterization and possible improvement to realize their promising potential.…”

Research Progress on Triarylmethyl Radical-Based High-Efficiency OLED

“…As the excitons are excited, they need to release energy in some way and return to the ground state [ 65 , 66 ]. There are two main ways to release energy: one is in the form of light radiation, and the other is in the form of non-radiation [ 67 ]. Generally, the radiation and non-radiation processes are similar to ebb and flow, which are related to the photoelectric conversion rate of the devices [ 68 , 69 , 70 ].…”