Charge Carrier Mobility Measurements in Tetracene Single Crystals

2005 ◽  
Vol 871 ◽  
Author(s):  
Jens Pflauma ◽  
Jens Niemax ◽  
Ashutosh Kumar Tripathi
Keyword(s):  
Deep Level ◽  
Hole Mobility ◽  
Charge Carrier Mobility ◽  
Hole Transport ◽  
Charge Carriers ◽  
Dispersive Transport ◽  
Temperature Dependent ◽  
Trap Energy ◽  
Multiple Trapping ◽  
Structural Imperfections

AbstractWe present data on the transport of charge carriers in the organic semiconductor tetracene. Comparative measurements by time-of-flight (TOF) spectroscopy and measurements in field-effect transistor (FET) geometry reveal hole mobilities of about 1 cm2/Vs. Whereas for FETs only hole transport can be detected, from TOF a strong dispersive transport for negative charge carriers is observed. This observation is mainly caused by deep-level trapping of electrons. By fitting the temperature dependent hole mobility to a model of multiple-trapping and release of charge carriers the trap energy and the relative trap density can be adjusted to 130 meV and 5·10-3, respectively. Comparative chemical and structural analysis of inhomogeneities show that the traps affecting the transport are mainly caused by chemical defects rather than by structural imperfections.

scholarly journals Effects of Molecular Structure on Intramolecular Charge Carrier Transport in Dithieno [3,2-b: -d] Pyrrole-Based Conjugated Copolymers

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Yoshihito Honsho ◽  
Akinori Saeki ◽  
Shu Seki
Keyword(s):  
Charge Carrier ◽  
Conjugated Polymer ◽  
Carrier Mobility ◽  
Carrier Transport ◽  
Hole Mobility ◽  
Charge Carrier Mobility ◽  
Charge Carriers ◽  
Coupling Reactions ◽  
Time Resolved ◽  
Yamamoto Coupling

Intramolecular mobility of positive charge carriers in conjugated polymer films based on dithieno [2,3-b: -d] pyrrole (DTP) is studied by time-resolved microwave conductivity (TRMC). A series of DTP homopolymer and copolymers combined with phenyl, 2,-biphenyl, thiophene, 2,-bithiophene, and 9,-dioctylfluorene were synthesized by Suzuki-Miyaura and Yamamoto coupling reactions. Polymers containing DTP unit are reported to show high value of hole mobility measured by FET method, and this type of polymers is expected to have stable HOMO orbitals which are important for hole transportation. Among these copolymers, DTP coupled with 9,-dioctylfluorene copolymer showed the highest charge carrier mobility as high as 1.7 cm2/Vs, demonstrating an excellent electrical property on rigid copolymer backbones.

Influence of the Distribution of Tail States in a-Si:H on the Field Dependence of Carrier Drift Mobilities

2004 ◽  
Vol 808 ◽  
Author(s):  
Monica Brinza ◽  
Evguenia V. Emelianova ◽  
André Stesmans ◽  
Guy J. Adriaenssens
Keyword(s):  
Field Dependence ◽  
Carrier Mobility ◽  
Transport Model ◽  
Chemical Vapor ◽  
Gaussian Component ◽  
Dispersive Transport ◽  
Exponential Distributions ◽  
Band Tail ◽  
Multiple Trapping ◽  
Gaussian Density

ABSTRACTExponential distributions of tail states have been able, within the framework of a multiple-trapping transport model, to account rather well for the time-of-flight photoconductivity transients that are measured with ‘standard’ a-Si:H, i.e. material prepared by plasma-enhanced chemical vapor deposition at ∼250°C. A field-dependent carrier mobility in the dispersive transport regime is part of the observations. However, samples prepared in an expanding thermal plasma, although still exhibiting the dispersive transients, fail to show this field dependence. The presence of a Gaussian component in the density of valence-band tail states can account for such behavior for the hole transients. Nanoscale ordered inclusions in the amorphous matrix are thought to be responsible for the Gaussian density of states contribution.

Modeling the Effect of Annealing and Regioregularity on Electron and Hole Transport Characteristics of Bulk Heterojunction Organic Photovoltaic Devices

2010 ◽  
Vol 1270 ◽  
Author(s):  
Shabnam Shambayati ◽  
Bobak Gholamkhass ◽  
Soheil Ebadian ◽  
Steven Holdcroft ◽  
Peyman Servati
Keyword(s):  
Annealing Time ◽  
Electron Mobility ◽  
Bulk Heterojunction ◽  
Acid Methyl Ester ◽  
Hole Mobility ◽  
Phase Segregation ◽  
Hole Transport ◽  
Trap States ◽  
Current Voltage ◽  
Steep Decline

AbstractIn this study, the dark current-voltage characteristics of electron-only and hole-only poly(3-hexyl thiophene) (P3HT):[6,6]-phenyl C61-butyric acid methyl ester (PCBM) as a function of regioregularity (RR) and annealing time is investigated using the mobility edge (ME) model. This model is used to analyze the degradation of electron and hole mobilities as a function of annealing time for 93%-RR and 98%-RR P3HT:PCBM devices. The hole mobility is almost unchanged by the RR nature of P3HT and thermal annealing. The electron mobility, however, behaves differently after annealing. The electron mobility of 98%-RR devices, which is initially higher than that of the 93%-RR devices, experiences a steep decline with annealing. Based on ME analysis, this is due to an increase in trap states in the exponential tail caused by phase segregation of solid state blends of 98%-RR polymer and PCBM. The electron mobility of 93%-RR devices increases with annealing due to an optimization of nano-phase separated morphology.

scholarly journals Progress on the Synthesis and Application of CuSCN Inorganic Hole Transport Material in Perovskite Solar Cells

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2592 ◽  
Author(s):  
Funeka Matebese ◽  
Raymond Taziwa ◽  
Dorcas Mutukwa
Keyword(s):  
Solar Cells ◽  
Energy Levels ◽  
Perovskite Solar Cells ◽  
Hole Mobility ◽  
Cost Effective ◽  
Vital Role ◽  
Hole Transport ◽  
Recombination Processes ◽  
Short Synthesis ◽  
P Type

P-type wide bandgap semiconductor materials such as CuI, NiO, Cu2O and CuSCN are currently undergoing intense research as viable alternative hole transport materials (HTMs) to the spiro-OMeTAD in perovskite solar cells (PSCs). Despite 23.3% efficiency of PSCs, there are still a number of issues in addition to the toxicology of Pb such as instability and high-cost of the current HTM that needs to be urgently addressed. To that end, copper thiocyanate (CuSCN) HTMs in addition to robustness have high stability, high hole mobility, and suitable energy levels as compared to spiro-OMeTAD HTM. CuSCN HTM layer use affordable materials, require short synthesis routes, require simple synthetic techniques such as spin-coating and doctor-blading, thus offer a viable way of developing cost-effective PSCs. HTMs play a vital role in PSCs as they can enhance the performance of a device by reducing charge recombination processes. In this review paper, we report on the current progress of CuSCN HTMs that have been reported to date in PSCs. CuSCN HTMs have shown enhanced stability when exposed to weather elements as the solar devices retained their initial efficiency by a greater percentage. The efficiency reported to date is greater than 20% and has a potential of increasing, as well as maintaining thermal stability.

scholarly journals Светоизлучающие полевые транзисторы на основе композитных пленок полифлуорена и нанокристаллов CsPbBr-=SUB=-3-=/SUB=-

2019 ◽  
Vol 61 (2) ◽  
pp. 388
Author(s):  
А.Н. Алешин ◽  
И.П. Щербаков ◽  
Д.А. Кириленко ◽  
Л.Б. Матюшкин ◽  
В.А. Мошников
Keyword(s):  
Field Effect Transistors ◽  
Composite Films ◽  
Hole Mobility ◽  
Hole Transport ◽  
Component Ratio ◽  
Organic Field Effect Transistors ◽  
Electrical And Optical Properties ◽  
Light Emitting ◽  
Current Voltage ◽  
Current Voltage Characteristics

Abstract—Light-emitting organic field-effect transistors (LE-FETs) on the basis of composite films that consist of perovskite nanocrystals (CsPbBr_3) embedded in a matrix of conjugated polymer—polyfluorene (PFO)—have been obtained, and their electrical and optical properties have been investigated. Output and transfer current-voltage characteristics (I-Vs) of FETs based on PFO : CsPbBr_3 films (component ratio 1 : 1) have a slight hysteresis at temperatures of 100–300 K and are characteristic of hole transport. The hole mobility is ∼3.3 and ∼1.9 cm^2/(V s) at the modes of the saturation and low fields, respectively, at 250 K and reaches ∼5 cm^2/(V s) at 100 K. It has been shown that the application of pulsed voltage to LE-FETs based on PFO : CsPbBr_3 can reduce the ionic conductivity and provide electroluminescence in this structure at 300 K.

Dispersive transport and multiple trapping in solid N2

1988 ◽  
Vol 40-41 ◽  
pp. 191-192 ◽  
Author(s):  
G. Zumofen ◽  
M. Loher ◽  
K. Dressler
Keyword(s):  
Dispersive Transport ◽  
Multiple Trapping ◽  
Solid N2
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