Reduced molybdenum oxide as an efficient electron injection layer in polymer light-emitting diodes

Vasilopoulou, Maria; Palilis, Leonidas C.; Georgiadou, Dimitra G.; Argitis, Panagiotis; Κέννου, Στέλλα; Sygellou, Labrini; Kostis, Ioannis; Papadimitropoulos, G.; Konofaos, N.; Iliadis, A.A.; Davazoglou, Dimitris

doi:10.1063/1.3557502

Cited by 52 publications

(27 citation statements)

References 14 publications

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“…Indeed, the films deposited by Vasilopoulou et al [10] are strongly oxygen deficient, which ensures that the Wf of their MoO 3 is small.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, the proposition of using MoO x as a CBL is not an incongruous idea, especially because MoO x tends to be metallic. Moreover, Vasilopoulou et al [10] showed that the electron injection in an OLED based on poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo [2,1,3]thiadiazol-4,8-diyl)] (F8BT) can be significantly improved by inserting a very thin layer (5 nm) of partially reduced molybdenum oxide (MoO 2.7 ) between the aluminum cathode and the organic emitting layer. Actually, after measuring the valence band maximum energy of MoO x by UPS to be equal to 7.1 eV and the band gap of MoO 3 to be 3 eV, they conclude that the conduction band minimum is at approximately 4.1 eV, which is in good agreement with the work function of Al (4.3 eV).…”

Section: Introductionmentioning

confidence: 99%

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Improvement in the Lifetime of Planar Organic Photovoltaic Cells through the Introduction of MoO3 into Their Cathode Buffer Layers

2014

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Recently, MoO 3 , which is typically used as an anode buffer layer in organic photovoltaic cells (OPVCs), has also been used as a cathode buffer layer (CBL). Here, we check its efficiency as a CBL using a planar heterojunction based on the CuPc/C 60 couple. The CBL is a bi-layer tris-(8-hydroxyquinoline) aluminum (Alq 3 )/MoO 3 . We show that the OPVC with MoO 3 in its CBL almost immediately exhibits lower efficiency than those using Alq 3 alone. Nevertheless, the OPVCs increase their efficiency during the first five to six days of air exposure. We explain this evolution of the efficiency of the OPVCs over time through the variation in the MoO 3 work function due to air contamination. By comparison to a classical OPVC using a CBL containing only Alq 3 , if it is found that the initial efficiency of the latter is higher, this result is no longer the same after one week of exposure to ambient air. Indeed, this result is due to the fact that the lifetime of the cells is significantly increased by the presence of MoO 3 in the CBL.

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“…Indeed, the films deposited by Vasilopoulou et al [10] are strongly oxygen deficient, which ensures that the Wf of their MoO 3 is small.…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Improvement in the Lifetime of Planar Organic Photovoltaic Cells through the Introduction of MoO3 into Their Cathode Buffer Layers

2014

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“…MoO 3 enhances hole injection into organic layers by reducing the energy level offset between the highest occupied molecular orbital (HOMO) of the organics and the Fermi level (E F ) of the anode electrode. Greiner et al [22] and Vasilopoulou et al [23] reported that the reduced MoO 3 film (MoOx and x $ 2.7) outperforms stoichiometric Mo trioxide film, due to the presence of defect states in the former. Some groups have emphasized on gap state (or defect state)-assisted transport at the MoO 3Àx /ITO interfaces [24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Electronic structure of MoO3−x/graphene interface

Zhao

Guo

et al. 2013

Carbon

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“…Generally, the hole transport in nanostructured MoO 3 layer occurs via the shallow defect states present in its band gap formed as a result of oxygen vacancies [93][94][95]. These oxygen vacancies serve as n-type dopants and lead to Fermi-level pinning at the photoactive layer-MoO 3 interface [96].…”

Section: Metal Oxide Semiconductors (Mos) As Anode Interfacial Layersmentioning

confidence: 99%

Metal oxide semiconducting interfacial layers for photovoltaic and photocatalytic applications

Elumalai

Chellappan

Jose

et al. 2015

Mater Renew Sustain Energy

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The present review rationalizes the significance of the metal oxide semiconductor (MOS) interfaces in the field of photovoltaics and photocatalysis. This perspective considers the role of interface science in energy harvesting using organic photovoltaics (OPVs) and dye-sensitized solar cells (DSSCs). These interfaces include large surface area junctions between photoelectrodes and dyes, the interlayer grain boundaries within the photoanodes, and the interfaces between photoactive layers and the top and bottom contacts. Controlling the collection and minimizing the trapping of charge carriers at these boundaries is crucial to overall power conversion efficiency of solar cells. Similarly, MOS photocatalysts exhibit strong variations in their photocatalytic activities as a function of band structure and surface states. Here, the MOS interface plays a vital role in the generation of OH radicals, which forms the basis of the photocatalytic processes. The physical chemistry and materials science of these MOS interfaces and their influence on device performance are also discussed.

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Reduced molybdenum oxide as an efficient electron injection layer in polymer light-emitting diodes

Cited by 52 publications

References 14 publications

Improvement in the Lifetime of Planar Organic Photovoltaic Cells through the Introduction of MoO3 into Their Cathode Buffer Layers

Improvement in the Lifetime of Planar Organic Photovoltaic Cells through the Introduction of MoO3 into Their Cathode Buffer Layers

Electronic structure of MoO3−x/graphene interface

Metal oxide semiconducting interfacial layers for photovoltaic and photocatalytic applications

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