Measurement of the lowest unoccupied molecular orbital energies of molecular organic semiconductors

Djurovich, Peter I.; Mayo, Elizabeth I.; Forrest, Stephen R.; Thompson, Mark E.

doi:10.1016/j.orgel.2008.12.011

Cited by 407 publications

(289 citation statements)

References 46 publications

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“…For the LUMO level of F4-TCNQ, we consider the value reported in literature of À 5.24 eV (ref. 46). Infrared spectra were recorded in transmission mode on a PerkinElmer Frontier FTIR spectrometer at room temperature.…”

Section: Methodsmentioning

confidence: 99%

How intermolecular geometrical disorder affects the molecular doping of donor–acceptor copolymers

et al. 2015

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Molecular doping of conjugated polymers represents an important strategy for improving organic electronic devices. However, the widely reported low efficiency of doping remains a crucial limitation to obtain high performance. Here we investigate how charge transfer between dopant and donor-acceptor copolymers is affected by the spatial arrangement of the dopant molecule with respect to the copolymer repeat unit. We p-dope a donor-acceptor copolymer and probe its charge-sensitive molecular vibrations in films by infrared spectroscopy. We find that, compared with a related homopolymer, a four times higher dopant/ polymer molar ratio is needed to observe signatures of charges. By DFT methods, we simulate the vibrational spectra, moving the dopant along the copolymer backbone and finding that efficient charge transfer occurs only when the dopant is close to the donor moiety. Our results show that the donor-acceptor structure poses an obstacle to efficient doping, with the acceptor moiety being inactive for p-type doping.

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Section: Methodsmentioning

confidence: 99%

How intermolecular geometrical disorder affects the molecular doping of donor–acceptor copolymers

et al. 2015

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“…6 As a consequence, using optical absorption to determine EA requires the knowledge of the exciton binding energy. 7 A second approach is to use easily accessible electrochemical methods. [8][9][10] These methods seek to correlate the IP, measured by means of PES, with the oxidation potential OP.…”

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confidence: 99%

“…Actually, linear relationships between these to magnitudes have been reported by several groups. [7][8][9][10] In cases where neither the IP nor the EA can be directly determined by photoemission techniques, cyclic-voltammetry can provide, besides the OP, the reduction potential from which, as discussed in Ref. 7, the EA can be derived through a linear relationship.…”

mentioning

confidence: 99%

“…[7][8][9][10] In cases where neither the IP nor the EA can be directly determined by photoemission techniques, cyclic-voltammetry can provide, besides the OP, the reduction potential from which, as discussed in Ref. 7, the EA can be derived through a linear relationship. Electrochemical techniques, however, have several shortcomings, one of them being the inaccuracy of the reference electrode potential, that limit its accuracy in optimal cases to ±0.1 eV.…”

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confidence: 99%

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Are Electron Affinity and Ionization Potential Intrinsic Parameters to Predict the Electron or Hole Acceptor Character of Amorphous Molecular Materials?

Louis¹,

San‐Fabián²,

Díaz-García³

et al. 2017

J. Phys. Chem. Lett.

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“…In the panel on the left, the LUMO and HOMO energies measured by IPES and UPS are indicated [11]. This is commonly referred to as the ''transport gap'' [16]. In the middle panel the LUMO energy is determined by adding the optical absorption.…”

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confidence: 99%

The role of interfaces in organic spin valves revealed through spectroscopic and transport measurements

Drew

Szulczewski

Nuccio

et al. 2011

Physica Status Solidi (b)

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Interfaces between dissimilar materials are critical to the performance of many electronic devices. In electrical devices where the active transport is through an organic semiconductor (OSC) layer there are metallic electrodes to supply and remove the charge carriers. At metal/molecule and molecule/metal interfaces the electrical contact is usually not Ohmic. As a result, in most metal-organic semiconductors-metal devices charge injection is mainly governed by tunneling across the barriers. When the metal electrodes are ferromagnetic the density of occupied and unoccupied electronic states is spindependent, which presents further subtleties to the electron transfer. In this article we summarize some of the important experimental results that have advanced our understanding of spin-polarized electron transfer across ferromagnetic metal (FM)/OSC interfaces. In particular, we highlight key spectroscopic studies that have revealed insights into the nature of the electronic structure between OSCs and FMs, in particular between Alq 3 and Co and Fe surfaces. We discuss the relationship between energy level diagrams for these systems and transport measurements made on spin-valve devices.

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Measurement of the lowest unoccupied molecular orbital energies of molecular organic semiconductors

Cited by 407 publications

References 46 publications

How intermolecular geometrical disorder affects the molecular doping of donor–acceptor copolymers

How intermolecular geometrical disorder affects the molecular doping of donor–acceptor copolymers

Are Electron Affinity and Ionization Potential Intrinsic Parameters to Predict the Electron or Hole Acceptor Character of Amorphous Molecular Materials?

The role of interfaces in organic spin valves revealed through spectroscopic and transport measurements

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