skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Charge transport across organic heterostructure: Role of interfacial density of states

Abstract

The mechanism of carrier transport across organic-organic hetero-interfaces is crucial for organic devices. For purposes of this study, we choose two hole transport materials 4, 4′, 4″-tris(N-3-methylphenyl-N-phenyl-amino) triphenyl-amine (m-MTDATA) and N, N′-diphenyl-N, N′-bis(1-naphthyl) (1, 1′-biphenyl)-4, 4′diamine. We demonstrate that transport across such interfaces can be controlled by introducing a thin undoped layer, which is chosen to be 10–30 nm of m-MTDATA layer in this particular case. By correlating the low frequency capacitance-voltage and temperature dependence of current density-voltage (J-V) characteristics, we show that the occupation of local density of states (LDOS) on both sides controls the transport at the hetero-interface and that it can be modified by the introduction of interlayer. The thickness of the undoped interlayer effectively acts as a control on carrier concentration at the interface leading to the modification of the effective energy offset, and overlap of the LDOS. The slope of the J-V characteristics in the exponential regime has a temperature dependent term and a purely voltage dependent term. The temperature dependence of J-V characteristics is explained by including field dependence of mobility and tunneling across LDOS. We trace the origin of the offset at the hetero-interface and estimate its values for the different cases consistent withmore » the proposed model of thermally assisted tunneling at the interface.« less

Authors:
 [1];  [2];  [1];  [2];  [2]
  1. Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208 016 (India)
  2. (India)
Publication Date:
OSTI Identifier:
22314627
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 6; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AMINES; BERYLLIUM 10; BIPHENYL; CAPACITANCE; CARRIERS; CHARGE TRANSPORT; CONCENTRATION RATIO; CURRENT DENSITY; DENSITY; ELECTRIC POTENTIAL; INTERFACES; LAYERS; TEMPERATURE DEPENDENCE; THICKNESS; TUNNEL EFFECT

Citation Formats

Tripathi, Durgesh C., Samtel Center for Display Technologies, Indian Institute of Technology Kanpur, Kanpur 208 016, Mohapatra, Y. N., Samtel Center for Display Technologies, Indian Institute of Technology Kanpur, Kanpur 208 016, and Materials Science Programme, Indian Institute of Technology Kanpur, Kanpur 208 016. Charge transport across organic heterostructure: Role of interfacial density of states. United States: N. p., 2014. Web. doi:10.1063/1.4892672.
Tripathi, Durgesh C., Samtel Center for Display Technologies, Indian Institute of Technology Kanpur, Kanpur 208 016, Mohapatra, Y. N., Samtel Center for Display Technologies, Indian Institute of Technology Kanpur, Kanpur 208 016, & Materials Science Programme, Indian Institute of Technology Kanpur, Kanpur 208 016. Charge transport across organic heterostructure: Role of interfacial density of states. United States. doi:10.1063/1.4892672.
Tripathi, Durgesh C., Samtel Center for Display Technologies, Indian Institute of Technology Kanpur, Kanpur 208 016, Mohapatra, Y. N., Samtel Center for Display Technologies, Indian Institute of Technology Kanpur, Kanpur 208 016, and Materials Science Programme, Indian Institute of Technology Kanpur, Kanpur 208 016. Thu . "Charge transport across organic heterostructure: Role of interfacial density of states". United States. doi:10.1063/1.4892672.
@article{osti_22314627,
title = {Charge transport across organic heterostructure: Role of interfacial density of states},
author = {Tripathi, Durgesh C. and Samtel Center for Display Technologies, Indian Institute of Technology Kanpur, Kanpur 208 016 and Mohapatra, Y. N. and Samtel Center for Display Technologies, Indian Institute of Technology Kanpur, Kanpur 208 016 and Materials Science Programme, Indian Institute of Technology Kanpur, Kanpur 208 016},
abstractNote = {The mechanism of carrier transport across organic-organic hetero-interfaces is crucial for organic devices. For purposes of this study, we choose two hole transport materials 4, 4′, 4″-tris(N-3-methylphenyl-N-phenyl-amino) triphenyl-amine (m-MTDATA) and N, N′-diphenyl-N, N′-bis(1-naphthyl) (1, 1′-biphenyl)-4, 4′diamine. We demonstrate that transport across such interfaces can be controlled by introducing a thin undoped layer, which is chosen to be 10–30 nm of m-MTDATA layer in this particular case. By correlating the low frequency capacitance-voltage and temperature dependence of current density-voltage (J-V) characteristics, we show that the occupation of local density of states (LDOS) on both sides controls the transport at the hetero-interface and that it can be modified by the introduction of interlayer. The thickness of the undoped interlayer effectively acts as a control on carrier concentration at the interface leading to the modification of the effective energy offset, and overlap of the LDOS. The slope of the J-V characteristics in the exponential regime has a temperature dependent term and a purely voltage dependent term. The temperature dependence of J-V characteristics is explained by including field dependence of mobility and tunneling across LDOS. We trace the origin of the offset at the hetero-interface and estimate its values for the different cases consistent with the proposed model of thermally assisted tunneling at the interface.},
doi = {10.1063/1.4892672},
journal = {Journal of Applied Physics},
number = 6,
volume = 116,
place = {United States},
year = {Thu Aug 14 00:00:00 EDT 2014},
month = {Thu Aug 14 00:00:00 EDT 2014}
}