Semiconductor nanocrystals(dots,rods,wires,etc.)exhibit a wide range of electrical and optical properties that differ from those of the corresponding bulk materials.These properties depend on both nanocrystal size and...Semiconductor nanocrystals(dots,rods,wires,etc.)exhibit a wide range of electrical and optical properties that differ from those of the corresponding bulk materials.These properties depend on both nanocrystal size and shape.Compared with nanodots,nanorods have an additional degree of freedom,the length or aspect ratio,and reduced symmetry,which leads to anisotropic properties.In this paper,we report the Au nanoparticle-catalyzed colloidal synthesis of monodisperse CdS nanorods.Based on systematic high resolution transmission electron microscopy studies,we propose a growth mechanism for these nanorods.展开更多
Excitonics,an alternative to romising for processing information since semiconductor electronics is rapidly approaching the end of Moore’s law.Currently,the development of excitonic devices,where exciton flow is cont...Excitonics,an alternative to romising for processing information since semiconductor electronics is rapidly approaching the end of Moore’s law.Currently,the development of excitonic devices,where exciton flow is controlled,is mainly focused on electric-field modulation or exciton polaritons in high-Q cavities.Here,we show an alloptical strategy to manipulate the exciton flow in a binary colloidal quantum well complex through mediation of the Förster resonance energy transfer(FRET)by stimulated emission.In the spontaneous emission regime,FRET naturally occurs between a donor and an acceptor.In contrast,upon stronger excitation,the ultrafast consumption of excitons by stimulated emission effectively engineers the excitonic flow from the donors to the acceptors.Specifically,the acceptors’stimulated emission significantly accelerates the exciton flow,while the donors’stimulated emission almost stops this process.On this basis,a FRET-coupled rate equation model is derived to understand the controllable exciton flow using the density of the excited donors and the unexcited acceptors.The results will provide an effective alloptical route for realizing excitonic devices under room temperature operation.展开更多
基金This work is supported by NSF-DMR 0547036,NSFCBET 0652042,and UB Integrated Nanostructured Systems Instrument Facilities.
文摘Semiconductor nanocrystals(dots,rods,wires,etc.)exhibit a wide range of electrical and optical properties that differ from those of the corresponding bulk materials.These properties depend on both nanocrystal size and shape.Compared with nanodots,nanorods have an additional degree of freedom,the length or aspect ratio,and reduced symmetry,which leads to anisotropic properties.In this paper,we report the Au nanoparticle-catalyzed colloidal synthesis of monodisperse CdS nanorods.Based on systematic high resolution transmission electron microscopy studies,we propose a growth mechanism for these nanorods.
基金financial support through the AcRF Tier1 grant(MOE2019-T1-002-087)the Singapore National Research Foundation for financial support under the Program of NRF-NRFI-2016-08financial support from the TUBA.
文摘Excitonics,an alternative to romising for processing information since semiconductor electronics is rapidly approaching the end of Moore’s law.Currently,the development of excitonic devices,where exciton flow is controlled,is mainly focused on electric-field modulation or exciton polaritons in high-Q cavities.Here,we show an alloptical strategy to manipulate the exciton flow in a binary colloidal quantum well complex through mediation of the Förster resonance energy transfer(FRET)by stimulated emission.In the spontaneous emission regime,FRET naturally occurs between a donor and an acceptor.In contrast,upon stronger excitation,the ultrafast consumption of excitons by stimulated emission effectively engineers the excitonic flow from the donors to the acceptors.Specifically,the acceptors’stimulated emission significantly accelerates the exciton flow,while the donors’stimulated emission almost stops this process.On this basis,a FRET-coupled rate equation model is derived to understand the controllable exciton flow using the density of the excited donors and the unexcited acceptors.The results will provide an effective alloptical route for realizing excitonic devices under room temperature operation.
