Hadar, I. ; Philbin, J. P. ; Panfil, Y. E. ; Neyshtadt, S. ; Lieberman, I. ; Eshet, H. ; Lazar, S. ; Rabani, E. ; Banin, U. .
Semiconductor Seeded Nanorods With Graded Composition Exhibiting High Quantum-Yield, High Polarization, And Minimal Blinking.
NANO LETTERS 2017,
17, 2524-2531.
AbstractSeeded semiconductor nanorods represent a unique family of quantum confined materials that manifest characteristics of mixed dimensionality. They show polarized emission with high quantum yield and fluorescence switching under an electric field, features that are desirable for use in display technologies and other optical applications. So far, their robust synthesis has been limited mainly to CdSe/CdS heterostructures, thereby constraining the spectral tunability to the red region of the visible spectrum. Herein we present a novel synthesis of CdSe/Cd1–xZnxS seeded nanorods with a radially graded composition that show bright and highly polarized green emission with minimal intermittency, as confirmed by ensemble and single nanorods optical measurements. Atomistic pseudopotential simulations elucidate the importance of the Zn atoms within the nanorod structure, in particular the effect of the graded composition. Thus, the controlled addition of Zn influences and improves the nanorods’ optoelectronic performance by providing an additional handle to manipulate the degree confinement beyond the common size control approach. These nanorods may be utilized in applications that require the generation of a full, rich spectrum such as energy-efficient displays and lighting.
Hadar, I. ; Philbin, J. ; Panfil, Y. ; Eshet, H. ; Rabani, E. ; Banin, U. .
Theoretical Investigation Of Novel Cdse/Cd1-XZnXS Seeded Nanorods Exhibiting High Quantum-Yield, High Polarization, And Minimal Blinking.
ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 2017,
253.
AbstractSeeded semiconductor nanorods manifest exceptional and desirable optical properties including tunable bright emission with linear polarization and high physical and chemical stability. These properties arise mainly from their unique mixed 0D-1D dimensionality at the nanoscale. Despite the significant advances and important work on seeded nanorods, until now their robust synthesis was limited to CdSe-seed/CdS-rods. This in turn constrained their color tunability mainly to the orange-red region of the visible spectrum and it has been difficult to obtain emission at higher wavelengths (green). In this talk, I will discuss how we used an all-atom, semiempirical pseudopotential model along with the Bethe-Salpeter equation to investigate seeded nanorods with homogeneously distributed Zn and graded shell compositions. Graded composition seeded nanorods were also synthesized and found to emit green light that is strongly linearly polarized along with having high quantum yields and reduced blinking compared to CdSe/CdS seeded nanorods - this is consistent with our computational study. Our theoretical model allowed us to explicitly show how the increase in the band and optical gaps are related to electron localization effects induced by the addition of Zn into the shell. Additionally, we found that a graded composition of Zn atoms (as opposed to homogenously distributed Zn) in the shell is vital to the enhanced linearly polarized absorption and emission of these novel seeded nanorods. Thus, the controlled addition of Zn influences and improves the nanorods opto-electronic properties by providing an additional handle to control the degree of electron confinement beyond the common size control approach. These seeded nanorods may be utilized in applications that require the generation of a full, rich spectrum such as energy efficient displays and lighting.
