Time-of-flight study of electrical charge mobilities in liquid-crystalline zinc octakis(β-octoxyethyl) porphyrin films

2000 ◽  
Vol 15 (11) ◽  
pp. 2494-2498 ◽  
Author(s):  
Yang Yuan ◽  
Brian A. Gregg ◽  
Marcus F. Lawrence
Keyword(s):  
Charge Transport ◽  
Liquid Crystalline ◽  
Room Temperature ◽  
Thick Films ◽  
Time Of Flight ◽  
Charge Carriers ◽  
Electrical Charge ◽  
Charged Carrier ◽  
Flight Measurements ◽  
Discotic Mesophase

Time-of-flight measurements performed on micron-thick films of liquid-crystalline zinc octakis(β-octoxyethyl) porphyrin indicated that charge carriers possess significantly high drift mobilities, attaining approximately 0.01 cm2 V−1s −1 and 0.008 cm2 V−1s −1 for holes and electrons, respectively, at room temperature. Upon heating the samples from 300 to 420 K, causing the porphyrin to go from the solid-crystalline to the discotic mesophase, the mobilities did not decrease drastically, and remained at values slightly larger than half those observed at room temperature. Charge transport in this material conformed to the Scher–Montroll model, which attributes a distribution of hopping times to the propagation of the initially formed charged carrier packet. Analysis of the “universal” plots prescribed by this model yielded a dispersion factor of 0.5 for both charge carriers.

Charge carrier lifetimes in a smectic liquid crystalline photoconductor of a 2-phenylnaphthalene derivative

2003 ◽  
Vol 771 ◽  
Author(s):  
Hiroaki Iino ◽  
Jun-Ichi Hanna
Keyword(s):  
Charge Carrier ◽  
Liquid Crystalline ◽  
Negative Charge ◽  
Ionic Conduction ◽  
Time Of Flight ◽  
Charge Carriers ◽  
The Other ◽  
Time Range ◽  
Electron Lifetime ◽  
Carrier Lifetimes

AbstractWe have investigated the charge carrier lifetimes for electrons and holes in smectic mesophases of a 2-phenylnaphthalene derivative, 6-(4'-octylphenyl)-2-dodecyloxynaphthalene (8-PNP-O12) by time-of-flight (TOF) measurement. For the negative charge carriers, we found two transits in different time range, which are attributed to electronic and ionic conduction. With the aid of liquid-like fluidity of the material, we could prepare very thick samples over 500μm, and it enables us to determine the carrier lifetimes, which are governed by different regimes: the hole lifetime is governed by recombination of charge carriers and estimated to be 10-2 sec; on the other hand, the electron lifetime is dominated by trapping at deep states and estimated to be on the order of 10-5 sec for both SmA and SmB phases.

scholarly journals Optical and Electrical Properties of Undoped Microcrystalline Silicon Deposited by the VHF-GD with Different Dilutions of Silane in Hydrogen

1996 ◽  
Vol 452 ◽  
Author(s):  
N. Beck ◽  
P. Orres ◽  
J. Fric ◽  
Z. Remeš ◽  
A. Poruba ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Room Temperature ◽  
Crystalline Silicon ◽  
Time Of Flight ◽  
Optical And Electrical Properties ◽  
Microcrystalline Silicon ◽  
Transient Time ◽  
Deep Traps ◽  
Flight Measurements ◽  
Strong Dilution

AbstractWe show that the optical and electrical properties of microcrystalline silicon (μc-Si:H) deposited by the VHF-GD technique at 110 MHz can considerably be tuned by changing the dilution ratio of silane to hydrogen.With increasing silane dilution we observe enhanced optical absorption for energies below 2 eV due to the transition of the material from amorphous / microcrystalline mixture to a pure microcrystalline phase. Simultaneously, the light scattering and the defect absorption increases. Strong dilution also promotes the incorporation of impurities into the material, leading to a pronounced extrinsic behaviour as seen from the decrease of the activiation energy of the electrical conductivity.The electrical properties were investigated in the dark by the Time of Flight technique. We measured drift mobilities at room temperature which slightly increase with dilution, reaching values of 3 cm2/Vs for electrons and 1.2 cm2/Vs for holes. The ratio between electron and hole drift mobilities is found to be around 2 for all samples studied, similar to that of crystalline silicon.Furthermore, post-transient Time of Flight measurements revealed detrimental electron deep traps in low dilution material.

Alkali Metal Chalcogenides for Radiation Detection

2011 ◽  
Vol 1341 ◽  
Author(s):  
J. A. Peters ◽  
Zhifu Liu ◽  
B. W. Wessels ◽  
I. Androulakis ◽  
C. P. Sebastian ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Alkali Metal ◽  
Charge Transport ◽  
Band Gap ◽  
Room Temperature ◽  
Gamma Ray ◽  
Radiation Detector ◽  
Radiation Detection ◽  
Charge Carriers ◽  
Metal Chalcogenides

ABSTRACTWe report on the optical and charge transport properties of novel alkali metal chalcogenides, Cs2Hg6S7 and Cs2Cd3Te4, pertaining to their use in radiation detection. Optical absorption, photoconductivity, and gamma ray response measurements for undoped crystals were measured. The band gap energies of the Cs2Hg6S7 and Cs2Cd3Te4 compounds are 1.63 eV and 2.45 eV, respectively. The mobility-lifetime products for charge carriers are of the order of ~10-3 cm2/V for electrons and ~10-4 cm2/V for holes. Detectors fabricated from the ternary compound Cs2Hg6S7 shows well-resolved spectroscopic features at room temperature in response to ϒ -rays at 122 keV from a 57Co source, indicating its potential as a radiation detector.

Time-of-Flight Measurements in a-Si:H Between Room Temperature and 130° C°

1987 ◽  
Vol 95 ◽  
Author(s):  
D. S. Shen ◽  
S. Aljishi ◽  
Z E. Smith ◽  
J. P. Conde ◽  
V. Chu ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Room Temperature ◽  
Time Of Flight ◽  
High Sensitivity ◽  
Drift Mobility ◽  
Hole Transport ◽  
Dispersive Transport ◽  
Band Tail ◽  
Flight Measurements

AbstractThe drift mobility μd and the mobility-lifetime product μτ in undoped a-Si:H have been studied up to 130°C. The electron μde is temperature-activated with Eae = 0.13 to 0.16 eV. The electron (μτ)e increases with temperature T. For hole transport, we observe the transition from dispersive to non-dispersive transport with increasing T. The hole μdh is ∼ 1/100 of μde, and is activated with Eah = 0.34 to 0.48eV. The hole (μτ)h does not change much with T. A computer simulation demonstrates the high sensitivity of μd to the band tail width.

Novel calamitic liquid crystalline organic semiconductors based on electron-deficient dibenzo[c,h][2,6]naphthyridine: synthesis, mesophase, and charge transport properties by the time-of-flight technique

2019 ◽  
Vol 7 (42) ◽  
pp. 13192-13202 ◽  
Author(s):  
Ming-Cong Yang ◽  
Jun-ichi Hanna ◽  
Hiroaki Iino
Keyword(s):  
Charge Transport ◽  
Transport Properties ◽  
Organic Semiconductors ◽  
Liquid Crystalline ◽  
Time Of Flight ◽  
Low Order

Mobility shows Poole–Frenkel like behaviour in the low order mesophase of liquid crystalline organic semiconductors based on an electron-deficient dibenzo[c,h][2,6]naphthyridine (DBN) derivative.

Ion mobility time-of-flight measurements: isolating the mobility of charge carriers during an epoxy–amine reaction

Polymer ◽  
2004 ◽  
Vol 45 (26) ◽  
pp. 8825-8835 ◽  
Author(s):  
Z. Guo ◽  
J. Warner ◽  
P. Christy ◽  
D.E. Kranbuehl ◽  
G. Boiteux ◽  
...  
Keyword(s):  
Ion Mobility ◽  
Time Of Flight ◽  
Charge Carriers ◽  
Epoxy Amine ◽  
Mobility Of Charge Carriers ◽  
Flight Measurements

Charge transport in poly(3-hexylthiophene):CdSe nanocrystals hybrid thin films investigated with time-of-flight measurements

2012 ◽  
Vol 101 (13) ◽  
pp. 133301 ◽  
Author(s):  
Elsa Couderc ◽  
Nicolas Bruyant ◽  
Angela Fiore ◽  
Frédéric Chandezon ◽  
David Djurado ◽  
...  
Keyword(s):  
Thin Films ◽  
Charge Transport ◽  
Time Of Flight ◽  
Cdse Nanocrystals ◽  
Hybrid Thin Films ◽  
Flight Measurements

scholarly journals Correction: Room temperature discotic liquid crystalline triphenylene-pentaalkynylbenzene dyads as an emitter in blue OLEDs and their charge transfer complexes with ambipolar charge transport behaviour

2020 ◽  
Vol 8 (10) ◽  
pp. 3603-3604
Author(s):  
Indu Bala ◽  
Wan-Yun Yang ◽  
Santosh Prasad Gupta ◽  
Joydip De ◽  
Rohit Ashok Kumar Yadav ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Charge Transport ◽  
Liquid Crystalline ◽  
Room Temperature ◽  
Charge Transfer Complexes ◽  
Transport Behaviour

Correction for ‘Room temperature discotic liquid crystalline triphenylene-pentaalkynylbenzene dyads as an emitter in blue OLEDs and their charge transfer complexes with ambipolar charge transport behaviour’ by Indu Bala et al., J. Mater. Chem. C, 2019, 7, 5724–5738.

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