Material design of organic thin films for bipolar charge transport

We investigate the charge transport mechanism in copper phthalocyanine thin films with and without traps. We find that the density of interface states at the grain boundaries can decide the mechanism of charge transport in organic thin films.

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Energy band and electron-vibration coupling in organic thin films: photoelectron spectroscopy as a powerful tool for studying the charge transport

Applied Physics A ◽

10.1007/s00339-008-4553-8 ◽

2008 ◽

Vol 92 (3) ◽

pp. 495-504 ◽

Cited By ~ 45

Author(s):

Nobuo Ueno ◽

Satoshi Kera ◽

Kazuyuki Sakamoto ◽

Koji. K. Okudaira

Keyword(s):

Thin Films ◽

Charge Transport ◽

Photoelectron Spectroscopy ◽

Energy Band ◽

Organic Thin Films ◽

Vibration Coupling

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Monte Carlo simulation of charge transport in disordered organic thin films: Applicability of Meyer-Neldel rule for extracting energetic disorder

10.1063/1.4791350 ◽

2013 ◽

Cited By ~ 1

Author(s):

S. Raj Mohan ◽

Manoranjan P. Singh ◽

M. P. Joshi ◽

L. M. Kukreja

Keyword(s):

Thin Films ◽

Monte Carlo Simulation ◽

Monte Carlo ◽

Charge Transport ◽

Organic Thin Films ◽

Energetic Disorder

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Negative field dependence of mobility in disordered organic thin films due to non-equilibrium charge transport

Organic Electronics ◽

10.1016/j.orgel.2010.07.002 ◽

2010 ◽

Vol 11 (10) ◽

pp. 1642-1648 ◽

Cited By ~ 6

Author(s):

S. Raj Mohan ◽

Manoranjan P. Singh ◽

M.P. Joshi

Keyword(s):

Thin Films ◽

Charge Transport ◽

Field Dependence ◽

Organic Thin Films ◽

Equilibrium Charge ◽

Negative Field ◽

Non Equilibrium

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Electron spectroscopy of functional organic thin films: Deep insights into valence electronic structure in relation to charge transport property

Progress in Surface Science ◽

10.1016/j.progsurf.2008.10.002 ◽

2008 ◽

Vol 83 (10-12) ◽

pp. 490-557 ◽

Cited By ~ 220

Author(s):

Nobuo Ueno ◽

Satoshi Kera

Keyword(s):

Thin Films ◽

Electronic Structure ◽

Charge Transport ◽

Transport Property ◽

Electron Spectroscopy ◽

Organic Thin Films ◽

Charge Transport Property ◽

Valence Electronic Structure

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Controlling Molecular Packing for Charge Transport in Organic Thin Films

Advanced Energy Materials ◽

10.1002/aenm.201000021 ◽

2011 ◽

Vol 1 (2) ◽

pp. 188-193 ◽

Cited By ~ 27

Author(s):

Liqiang Li ◽

Wenping Hu ◽

Harald Fuchs ◽

Lifeng Chi

Keyword(s):

Thin Films ◽

Charge Transport ◽

Organic Thin Films ◽

Molecular Packing

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Carrier Induced Hopping to Band Conduction in Pentacene

Scientific Reports ◽

10.1038/s41598-019-56558-w ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 2

Author(s):

Varsha Rani ◽

Pramod Kumar ◽

Akanksha Sharma ◽

Sarita Yadav ◽

Budhi Singh ◽

...

Keyword(s):

Thin Films ◽

Charge Transport ◽

Carrier Mobility ◽

Density Functional ◽

Energy Levels ◽

Organic Thin Films ◽

High Density ◽

Hopping Transport ◽

Gaussian Density ◽

Band Conduction

AbstractCharge transport in organic thin films which are generally polycrystalline is typically limited by the localization of the carriers at lattice defects resulting in low carrier mobilities and carriers move from one state to another state by hopping. However, charge transport in organic semiconductors in their single crystalline phase is coherent due to band conduction and mobilities are not limited by disorder resulting in higher carrier mobility. So it is a challenge to enhance the carrier mobility in a thin film which is the preferred choice for all organic devices. Here, we show that it is possible to increase the carrier mobility in polycrystalline thin films by injecting sufficient carriers such that Fermi level can be moved into the region of high density in Gaussian density of states of molecular solids. When the hopping transport happens through the molecular energy levels whose density is low, mobility is decided by incoherent transport however, when the the hopping transport happens through the energy levels with high density, mobility is decided by coherent transport, as in band conduction. We present results highlighting the observation of both band-like and hopping conduction in polycrystalline organic thin films by varying the concentration of injected charge. More importantly the transition from hopping to band transport is reversible. The observed carrier mobilities in both the regimes match well with theoretical estimates of hopping mobility and band mobility determined from first principles density functional theory.

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The study of charge transport through organic thin films: mechanism, tools and applications

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2007.2029 ◽

2007 ◽

Vol 365 (1855) ◽

pp. 1509-1537 ◽

Cited By ~ 46

Author(s):

Emily A Weiss ◽

Jennah K Kriebel ◽

Maria-Anita Rampi ◽

George M Whitesides

Keyword(s):

Thin Films ◽

Charge Transport ◽

Organic Molecules ◽

Organic Thin Films ◽

Theoretical Models ◽

Experimental Methods ◽

Self Assembled Monolayers ◽

Current State ◽

Molecular Scale ◽

Assembled Monolayers

In this paper, we discuss the current state of organic and molecular-scale electronics, some experimental methods used to characterize charge transport through molecular junctions and some theoretical models (superexchange and barrier tunnelling models) used to explain experimental results. Junctions incorporating self-assembled monolayers of organic molecules—and, in particular, junctions with mercury-drop electrodes—are described in detail, as are the issues of irreproducibility associated with such junctions (due, in part, to defects at the metal–molecule interface).

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