Related Experiment Video
Updated: Jun 10, 2026
08:43
Effect of Bending on the Electrical Characteristics of Flexible Organic Single Crystal-based Field-effect Transistors
Published on: November 7, 2016
Band-like temperature dependence of mobility in a solution-processed organic semiconductor
Nature Materials
|August 24, 2010
Summary
Charges in organic semiconductors are localized in shallow traps at low temperatures, not band conduction. Moderate electric fields enable detrapping, revealing localized transport limited by lattice fluctuations at room temperature.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Organic Electronics
Background:
- Solution-processed organic semiconductors exhibit room-temperature mobilities of 1-5 cm(2) V(-1) s(-1).
- A key debate in organic electronics is whether charge transport relies on localized states or extended band conduction.
- Low-temperature studies of molecular crystals show evidence for extended-state conduction.
Discussion:
- Investigating the apparent negative temperature coefficient of mobility (dmu/dT<0) in 6,13-bis(triisopropylsilylethynyl)-pentacene films.
- Utilizing optical spectroscopy to probe gate-induced charge carriers.
- Analyzing charge carrier behavior under varying lateral electric fields and temperatures.
Key Insights:
- At low temperatures and low fields, charges localize in shallow traps on individual molecules.
- Moderate lateral electric fields can detrap charges, leading to nonlinear transport at low temperatures.
- The observed negative temperature coefficient of mobility at high fields arises from localized transport influenced by thermal lattice fluctuations, not extended-state conduction.
Outlook:
- Understanding charge localization mechanisms is crucial for designing high-performance organic electronic devices.
- Further research can explore strategies to mitigate trapping effects and enhance charge mobility.
- This study clarifies fundamental charge transport physics in organic semiconductors, guiding future material design.
Related Concept Videos
01:22Semiconductors
There is variation in the electrical conductivity of materials - metals, semiconductors, and insulators that are showcased with the help of the energy band diagrams.
Metals such as copper (Cu), zinc (Zn), or lead (Pb) have low resistivity and feature conduction bands that are either not fully occupied or overlap with the valence band, making a bandgap non-existent. This allows electrons in the highest energy levels of the valence band to easily transition to the conduction band upon gaining...
Metals such as copper (Cu), zinc (Zn), or lead (Pb) have low resistivity and feature conduction bands that are either not fully occupied or overlap with the valence band, making a bandgap non-existent. This allows electrons in the highest energy levels of the valence band to easily transition to the conduction band upon gaining...
01:27Biasing of Metal-Semiconductor Junctions
Biasing metal-semiconductor junctions involves applying a voltage across the junction. Specifically, the metal is connected to a voltage source, while the semiconductor is grounded. This technique is essential for controlling the direction and magnitude of current flow in electronic devices, including diodes, transistors, and photovoltaic cells.
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
01:20Types of Semiconductors
Intrinsic semiconductors are highly pure materials with no impurities. At absolute zero, these semiconductors behave as perfect insulators because all the valence electrons are bound, and the conduction band is empty, disallowing electrical conduction. The Fermi level is a concept used to describe the probability of occupancy of energy levels by electrons at thermal equilibrium. In intrinsic semiconductors, the Fermi level is positioned at the midpoint of the energy gap at absolute zero. When...
02:35Band Theory
When two or more atoms come together to form a molecule, their atomic orbitals combine and molecular orbitals of distinct energies result. In a solid, there are a large number of atoms, and therefore a large number of atomic orbitals that may be combined into molecular orbitals. These groups of molecular orbitals are so closely placed together to form continuous regions of energies, known as the bands.
The energy difference between these bands is known as the band gap.
Conductor, Semiconductor,...
The energy difference between these bands is known as the band gap.
Conductor, Semiconductor,...
02:55Temperature Dependence on Reaction Rate
The Collision Theory
Atoms, molecules, or ions must collide before they can react with each other. Atoms must be close together to form chemical bonds. This premise is the basis for a theory that explains many observations regarding chemical kinetics, including factors affecting reaction rates.
The collision theory is based on the postulates that (i) the reaction rate is proportional to the rate of reactant collisions, (ii) the reacting species collide in an orientation allowing contact between...
Atoms, molecules, or ions must collide before they can react with each other. Atoms must be close together to form chemical bonds. This premise is the basis for a theory that explains many observations regarding chemical kinetics, including factors affecting reaction rates.
The collision theory is based on the postulates that (i) the reaction rate is proportional to the rate of reactant collisions, (ii) the reacting species collide in an orientation allowing contact between...
01:21Carrier Transport
The generation of electrical current in semiconductors is fundamentally driven by two mechanisms: drift and diffusion. These processes are essential for the functionality and performance of semiconductor-based devices.
Drift Current:
The drift of charge carriers is started by an external electric field (E). Charged particles, such as electrons and holes, experience an acceleration between collisions with lattice atoms. For electrons, this results in a drift velocity (vd) given by:
Drift Current:
The drift of charge carriers is started by an external electric field (E). Charged particles, such as electrons and holes, experience an acceleration between collisions with lattice atoms. For electrons, this results in a drift velocity (vd) given by: