scholarly journals Charge carrier mobility in a two-phase disordered organic system in the low-carrier concentration regime

2013 ◽  
Vol 88 (12) ◽  
Author(s):  
Cristiano F. Woellner ◽  
Zi Li ◽  
José A. Freire ◽  
Gang Lu ◽  
Thuc-Quyen Nguyen
1994 ◽  
Vol 08 (16) ◽  
pp. 947-958 ◽  
Author(s):  
MD. ABDUL MALIK ◽  
V. D. REDDY ◽  
P. VENUGOPAL REDDY ◽  
D. R. SAGAR ◽  
PRANKISHAN

Electrical conductivity (σ) and thermopower measurements have been carried out on some Mg 1+x Ge x Fe 2−2x O 4 (0 < x < 0.4) ferrite samples over a temperature range 300–700 K. Using the experimental values of Seebeck coefficient at various temperatures, the values of charge carrier concentration have been determined. On the basis of the temperature variation of charge carrier mobility, the conduction mechanism in these ferrites has been discussed.


2011 ◽  
Vol 25 (13) ◽  
pp. 1757-1774
Author(s):  
DALAL. M. HEMEDA ◽  
ABDEL-RAOOF TAWFIK ◽  
OSAMA. M. HEMEDA ◽  
SALLY DEWIDAR

Polycrystalline garnet ferrites Dy 3-x Ni x Fe 5 O 12, where (x = 0.0, 0.1, 0.2, 0.3, 0.4, and 0.5) have been prepared by the standard ceramic technique and their crystalline structure were identified by X-ray diffraction and IR spectroscopy. The differential thermal analysis (DTA) reveals two peaks. It is observed that an endothermic peak between 587 and 498 K for all samples which is due to the magnetic phase change from ferrimagnetic to paramagnetic state. The exothermic peak at about 700 K may be attributed to the crystallization of Dy 3-x Ni x Fe 5 O 12 with garnet structure. DC electrical resistivity, thermoelectric power, charge carrier concentration and charge carrier mobility have been studied at different temperatures: It was found that the DC electrical conductivity increases linearly with increasing temperature ensuring the semiconducting nature of samples. The values of the thermoelectric power were negative for samples of 0.0 < x < 0.4 indicating that the majority of the charge carrier are electrons in these samples while it was positive for sample of x = 0.5 at room temperature, and negative at high temperature. Using the values of the DC electrical conductivity and thermoelectric power, the values of the charge carrier concentration and the charge carrier mobility were calculated. Finally thermal properties have been studied.


RSC Advances ◽  
2014 ◽  
Vol 4 (98) ◽  
pp. 55328-55333 ◽  
Author(s):  
B. Endrődi ◽  
J. Mellár ◽  
Z. Gingl ◽  
C. Visy ◽  
C. Janáky

Enhanced thermoelectric properties of poly(3-hexylthiophene) nanofiber networks were achieved, through controlling both charge carrier concentration and charge carrier mobility.


2018 ◽  
Author(s):  
Francesco Salerno ◽  
Beth Rice ◽  
Julia Schmidt ◽  
Matthew J. Fuchter ◽  
Jenny Nelson ◽  
...  

<p>The properties of an organic semiconductor are dependent on both the chemical structure of the molecule involved, and how it is arranged in the solid-state. It is challenging to extract the influence of each individual factor, as small changes in the molecular structure often dramatically change the crystal packing and hence solid-state structure. Here, we use calculations to explore the influence of the nitrogen position on the charge mobility of a chiral organic molecule when the crystal packing is kept constant. The transfer integrals for a series of enantiopure aza[6]helicene crystals sharing the same packing were analysed in order to identify the best supramolecular motifs to promote charge carrier mobility. The regioisomers considered differ only in the positioning of the nitrogen atom in the aromatic scaffold. The simulations showed that even this small change in the chemical structure has a strong effect on the charge transport in the crystal, leading to differences in charge mobility of up to one order of magnitude. Some aza[6]helicene isomers that were packed interlocked with each other showed high HOMO-HOMO integrals (up to 70 meV), whilst molecules arranged with translational symmetry generally afforded the highest LUMO-LUMO integrals (40 - 70 meV). As many of the results are not intuitively obvious, a computational approach provides additional insight into the design of new semiconducting organic materials.</p>


2019 ◽  
Vol 7 (22) ◽  
pp. 6649-6655
Author(s):  
A. López-Andarias ◽  
C. Atienza ◽  
J. López-Andarias ◽  
W. Matsuda ◽  
T. Sakurai ◽  
...  

Effect of the peptide-based quaterthiophene self-assembly process on the charge mobility properties of the n/p-materials formed is studied.


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