Coherent exciton-phonon coupling in CdSe/ZnS nanocrystals have been investigated by temperature-dependent two-dimensional electronic spectroscopy （2DES） measurements. Benefiting from the ability of 2DES to dissect a...Coherent exciton-phonon coupling in CdSe/ZnS nanocrystals have been investigated by temperature-dependent two-dimensional electronic spectroscopy （2DES） measurements. Benefiting from the ability of 2DES to dissect assembles in nanocrystal films, we have dearly identified experimental evidences of coherent coupling between exciton and phonon in CdSe/ZnS nanocrystals. In time domain, 2DES signals of excitonic transitions beat at a frequency resonant to a longitudinal optical phonon mode; in energy domain, phonon side bands are distinct at both Stokes and anti-Stokes sides. When temperature increases, phonon-induced exciton dephasing is observed with dramatic broadening of homogeneous linewidth. The results suggest exciton-phonon coupling is essential in elucidating the quantum dynamics of excitonic transitions in semiconductor nanocrystals.展开更多
Two dimensional Fourier transforrn electronic spectroscopy （2DES） in the visible region enables direct observation of complex dynamics of molecules including quantum coherence in the condensed phase. This review aim...Two dimensional Fourier transforrn electronic spectroscopy （2DES） in the visible region enables direct observation of complex dynamics of molecules including quantum coherence in the condensed phase. This review aims to provide a bridge between the principles and intuitive physical description of 2DES for tutorial purpose. Special emphasis is laid upon how 2DES circumvents the restrictions from both uncertainty principle and the wave-packet collapse during the coherent detection, leading to the successful detection of the coherence in terms of energy difference between the eigenstates showing as the quantum beats; then upon the possible mixing among the pure electronic transition, single-rnode and multi-mode coupled vibronic transition leading to the observed beating phenomena. Finally, recent ad- vances in experimentally distinguishing between the electronic coherence and the vibrational coherence are briefly discussed.展开更多
文摘Coherent exciton-phonon coupling in CdSe/ZnS nanocrystals have been investigated by temperature-dependent two-dimensional electronic spectroscopy （2DES） measurements. Benefiting from the ability of 2DES to dissect assembles in nanocrystal films, we have dearly identified experimental evidences of coherent coupling between exciton and phonon in CdSe/ZnS nanocrystals. In time domain, 2DES signals of excitonic transitions beat at a frequency resonant to a longitudinal optical phonon mode; in energy domain, phonon side bands are distinct at both Stokes and anti-Stokes sides. When temperature increases, phonon-induced exciton dephasing is observed with dramatic broadening of homogeneous linewidth. The results suggest exciton-phonon coupling is essential in elucidating the quantum dynamics of excitonic transitions in semiconductor nanocrystals.
基金supported by the National Natural Science Foundation of China (No.21227003, No.21433014, No.11721404)
文摘Two dimensional Fourier transforrn electronic spectroscopy （2DES） in the visible region enables direct observation of complex dynamics of molecules including quantum coherence in the condensed phase. This review aims to provide a bridge between the principles and intuitive physical description of 2DES for tutorial purpose. Special emphasis is laid upon how 2DES circumvents the restrictions from both uncertainty principle and the wave-packet collapse during the coherent detection, leading to the successful detection of the coherence in terms of energy difference between the eigenstates showing as the quantum beats; then upon the possible mixing among the pure electronic transition, single-rnode and multi-mode coupled vibronic transition leading to the observed beating phenomena. Finally, recent ad- vances in experimentally distinguishing between the electronic coherence and the vibrational coherence are briefly discussed.
