scholarly journals Ultrafast Spectroelectrochemistry Reveals Photoinduced Carrier Dynamics in Positively Charged CdSe Nanocrystals

2021 ◽  
Author(s):  
Alireza Honarfar ◽  
Pavel Chabera ◽  
Weihua Lin ◽  
Jie Meng ◽  
Hassan Mourad ◽  
...  
Keyword(s):  
Carrier Dynamics ◽  
Cdse Nanocrystals ◽  
Positively Charged

Electrochemical Evaluation of Dopant Energetics and the Modulation of Ultrafast Carrier Dynamics in Cu-Doped CdSe Nanocrystals

2017 ◽  
Vol 121 (48) ◽  
pp. 27233-27240 ◽  
Author(s):  
Sourav Maiti ◽  
Jayanta Dana ◽  
Yogesh Jadhav ◽  
Tushar Debnath ◽  
Santosh K. Haram ◽  
...  
Keyword(s):  
Carrier Dynamics ◽  
Cdse Nanocrystals ◽  
Ultrafast Carrier Dynamics ◽  
Ultrafast Carrier ◽  
Electrochemical Evaluation

Symmetry Breaking Induced Activation of Nanocrystal Optical Transitions

MRS Advances ◽  
2018 ◽  
Vol 3 (14) ◽  
pp. 711-716 ◽  
Author(s):  
Peter C. Sercel ◽  
Andrew Shabaev ◽  
Alexander L. Efros
Keyword(s):  
Optical Properties ◽  
Fine Structure ◽  
Symmetry Breaking ◽  
Semiconductor Nanocrystals ◽  
Radiative Lifetime ◽  
Multipole Expansion ◽  
Cdse Nanocrystals ◽  
Coulomb Center ◽  
Charged Center ◽  
Positively Charged

ABSTRACTWe have analysed the effect of symmetry breaking on the optical properties of semiconductor nanocrystals due to doping by charged impurities. Using doped CdSe nanocrystals as an example, we show the effects of a Coulomb center on the exciton fine-structure and optical selection rules using symmetry theory and then quantify the effect of symmetry breaking on the exciton fine structure, modelling the charged center using a multipole expansion. The model shows that the presence of a Coulomb center breaks the nanocrystal symmetry and affects its optical properties through mixing and shifting of the hole spin and parity sublevels. This symmetry breaking, particularly for positively charged centers, shortens the radiative lifetime of CdSe nanocrystals even at room temperature, in qualitative agreement with the increase in PL efficiency observed in CdSe nanocrystals doped with positive Ag charge centers [A. Sahu et.al., Nano Lett. 12, 2587, (2012)]. The effect of the charged center on the photoluminescence and the absorption spectra is shown, with and without the presence of compensating charges on the nanocrystal surface. While spectra of individual nanocrystals are expected to shift and broaden with the introduction of a charged center, configuration averaging and inhomogeneous broadening are shown to wash out these effects. The presence of compensating charges at the NC surface also serves to stabilize the band edge transition energies relative to NCs with no charge centers.

Modification of carrier dynamics in CdSe nanocrystals by excess Cd in deposition bath

2007 ◽  
Vol 36 (2) ◽  
pp. 205-210 ◽  
Author(s):  
Miroslav Šimurda ◽  
Petr Němec ◽  
František Trojánek ◽  
Karel Neudert ◽  
Tadaki Miyoshi ◽  
...  
Keyword(s):  
Carrier Dynamics ◽  
Cdse Nanocrystals

Ammonia effect on surface-mediated carrier dynamics in CdSe nanocrystals

2006 ◽  
Vol 503 (1-2) ◽  
pp. 64-68 ◽  
Author(s):  
Miroslav Šimurda ◽  
Petr Němec ◽  
Jana Preclíková ◽  
František Trojánek ◽  
Tadaki Miyoshi ◽  
...  
Keyword(s):  
Carrier Dynamics ◽  
Cdse Nanocrystals

Ultrafast Carrier Dynamics and Hot Electron Extraction in Tetrapod-Shaped CdSe Nanocrystals

2015 ◽  
Vol 7 (15) ◽  
pp. 7938-7944 ◽  
Author(s):  
Pengtao Jing ◽  
Wenyu Ji ◽  
Xi Yuan ◽  
Songnan Qu ◽  
Renguo Xie ◽  
...  
Keyword(s):  
Carrier Dynamics ◽  
Cdse Nanocrystals ◽  
Hot Electron ◽  
Ultrafast Carrier Dynamics ◽  
Ultrafast Carrier ◽  
Electron Extraction

Ultrafast Carrier Dynamics of Photo-Induced Cu-Doped CdSe Nanocrystals

2018 ◽  
Vol 122 (29) ◽  
pp. 16992-17000 ◽  
Author(s):  
Avisek Dutta ◽  
Rajesh Bera ◽  
Arnab Ghosh ◽  
Amitava Patra
Keyword(s):  
Carrier Dynamics ◽  
Cdse Nanocrystals ◽  
Ultrafast Carrier Dynamics ◽  
Ultrafast Carrier

Protamine-DNA interaction

1978 ◽  
Vol 36 (2) ◽  
pp. 200-201
Author(s):  
D.P. Bazett-Jones ◽  
F.P. Ottensmeyer
Keyword(s):  
Small Volume ◽  
Double Helix ◽  
Dna Interaction ◽  
Dark Field ◽  
Sperm Head ◽  
Nuclear Proteins ◽  
Field Electron Microscopy ◽  
Dark Field Electron ◽  
Dna Double Helix ◽  
Positively Charged

Dark field electron microscopy has been used for the study of the structure of individual macromolecules with a resolution to at least the 5Å level. The use of this technique has been extended to the investigation of structure of interacting molecules, particularly the interaction between DNA and fish protamine, a class of basic nuclear proteins of molecular weight 4,000 daltons.Protamine, which is synthesized during spermatogenesis, binds to chromatin, displaces the somatic histones and wraps up the DNA to fit into the small volume of the sperm head. It has been proposed that protamine, existing as an extended polypeptide, winds around the minor groove of the DNA double helix, with protamine's positively-charged arginines lining up with the negatively-charged phosphates of DNA. However, viewing protamine as an extended protein is inconsistent with the results obtained in our laboratory.

Structure and Interaction of Protamine by Dark Field Electron Microscopy

1976 ◽  
Vol 34 ◽  
pp. 160-161
Author(s):  
D.P. Bazett-Jones ◽  
F.P. Ottensmeyer
Keyword(s):  
Electron Microscopy ◽  
Dark Field ◽  
Amino Acid Sequences ◽  
Dimensional Structure ◽  
3 Dimensional ◽  
Field Electron ◽  
Proposed Model ◽  
Field Electron Microscopy ◽  
Dark Field Electron ◽  
Positively Charged

It has been shown for some time that it is possible to obtain images of small unstained proteins, with a resolution of approximately 5Å using dark field electron microscopy (1,2). Applying this technique, we have observed a uniformity in size and shape of the 2-dimensional images of pure specimens of fish protamines (salmon, herring (clupeine, Y-l) and rainbow trout (Salmo irideus)). On the basis of these images, a model for the 3-dimensional structure of the fish protamines has been proposed (2).The known amino acid sequences of fish protamines show stretches of positively charged arginines, separated by regions of neutral amino acids (3). The proposed model for protamine structure (2) consists of an irregular, right-handed helix with the segments of adjacent arginines forming the loops of the coil.

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