Radiative recombination from dark excitons in nanocrystals: Activation mechanisms and polarization properties

Article

关键词: CDSE QUANTUM DOTS;    BAND-EDGE EXCITON;    FINE-STRUCTURE;    EXCHANGE INTERACTION;    SIZE DEPENDENCE;    SPECTROSCOPY;    MICROCRYSTALS;    ENHANCEMENT;    ORIENTATION;    CONFINEMENT;   

DOI  :  10.1103/PhysRevB.93.155427

来源: SCIE

【 摘 要 】

We analyze theoretically physical mechanisms responsible for the radiative recombination of the ground optically passive (dark) exciton (DE), which dominates in photoluminescence (PL) of colloidal nanocrystals (NCs) at low temperatures. The DE becomes optically active due to its mixing with the bright excitons caused by an external magnetic field, dangling-bond spins or by acoustic and optical phonons. These activation mechanisms mix the DE with different bright excitons and, consequently, lead to different PL polarization properties, because they are determined by dipole orientations of the bright excitons, which the DE is coupled with. We show that the PL polarization properties of prolate and oblate shape NCs are different due to different activation mechanisms responsible for the DE recombination.

【 授权许可】

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