Highly efficient simplified organic light emitting diodes

Meyer, Jens; Hamwi, Sami; Bülow, Tim; Johannes, H.‐H.; Riedl, Thomas; Kowalsky, Wolfgang

doi:10.1063/1.2784176

Cited by 253 publications

(144 citation statements)

References 18 publications

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“…Many reports can be found in the literature regarding interface engineering with TMOs applied to organic light emitting diodes (OLEDs) and organic solar cells [10], such as molybdenum trioxide (MoO 3 ) [11], tungsten trioxide (WO 3 ) [12], vanadium pentoxide (V 2 O 5 ) [13] and rhenium trioxide (ReO 3 ) [14]. These TMOs work as hole-selective contacts due to their large work functions (>5 eV) laying close to the Highest Occupied Molecular Orbital (HOMO) level of several ptype organic semiconductors, favoring ohmic contact formation.…”

Section: Introductionmentioning

confidence: 99%

Transition metal oxides as hole-selective contacts in silicon heterojunctions solar cells

Gerling

Mahato

Morales-Vilches

et al. 2016

Solar Energy Materials and Solar Cells

361

281

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This work reports on a comparative study comprising three transition metal oxides, MoO 3 , WO 3 and V 2 O 5 , acting as front p-type emitters for n-type crystalline silicon heterojunction solar cells. Owing to their high work functions (>5 eV) and wide energy band gaps, these oxides act as transparent hole-selective contacts with semiconductive properties that are determined by oxygen-vacancy defects (MoO 3-x ), as confirmed by x-ray photoelectron spectroscopy. In the fabricated hybrid structures, 15 nm thick transition metal oxide layers were deposited by vacuum thermal evaporation. Of all three devices, the V 2 O 5 /n-silicon heterojunction performed the best with a conversion efficiency of 15.7% and an open-circuit voltage of 606 mV, followed by MoO 3 (13.6%) and WO 3 (12.5%). These results bring into view a new silicon heterojunction solar cell concept with advantages such as the absence of toxic dopant gases and a simplified low-temperature fabrication process.

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Section: Introductionmentioning

confidence: 99%

Transition metal oxides as hole-selective contacts in silicon heterojunctions solar cells

Gerling

Mahato

Morales-Vilches

et al. 2016

Solar Energy Materials and Solar Cells

361

281

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“…Recently, transition metal oxides (TMOs) [1,2], such molybdenum trioxide (MoO 3 ) [3], tungsten oxide (WO 3 ) [4], vanadium pentoxide (V 2 O 5 ) [5] and rhenium trioxide (ReO 3 ) [6], have gained great attention because of their wide applications in optoelectronic devices composed of organic semiconductors (OSs). For example, in organic light-emitting diodes (OLEDs) [7], they are used as anode modification interlayers [3], which can substantially reduce the hole injection barrier.…”

Section: Introductionmentioning

confidence: 99%

Transition metal oxides on organic semiconductors

Zhao

Zhang

Liu

et al. 2014

Organic Electronics

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a b s t r a c tTransition metal oxides (TMOs) on organic semiconductors (OSs) structure has been widely used in inverted organic optoelectronic devices, including inverted organic light-emitting diodes (OLEDs) and inverted organic solar cells (OSCs), which can improve the stability of such devices as a result of improved protection of air sensitive cathode. However, most of these reports are focused on the anode modification effect of TMO and the nature of TMO-on-OS is not fully understood. Here we show that the OS on TMO forms a two-layer structure, where the interface mixing is minimized, while for TMO-on-OS, due to the obvious diffusion of TMO into the OS, a doping-layer structure is formed. This is evidenced by a series of optical and electrical studies. By studying the TMO diffusion depth in different OS, we found that this process is governed by the thermal property of the OS. The TMO tends to diffuse deeper into the OS with a lower evaporation temperature. It is shown that the TMO can diffuse more than 20 nm into the OS, depending on the thermal property of the OS. We also show that the TMO-on-OS structure can replace the commonly used OS with TMO doping structure, which is a big step toward in simplifying the fabrication process of the organic optoelectronic devices.

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“…Transition metal oxides (TMO) such as molybdenum oxide (MoO 3 ), vanadium oxide (V 2 O 5 ), or tungsten oxide (WO 3 ), have been extensively researched over the past few years as possible high-work-function (WF) hole-injection (extraction) materials for organic electronics. It is thought that the use of TMOs can lead to a significant performance enhancement of organic light-emitting diodes (OLED), organic transistors and organic photovoltaic cells (OPV).…”

Section: Introductionmentioning

confidence: 99%

Electronic structure of molybdenum-oxide films and associated charge injection mechanisms in organic devices

Meyer

2011

J. Photon. Energy

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Abstract. We report on the electronic structure of freshly evaporated and air-exposed Molybdenum tri-oxide (MoO 3 ) and the energy-level alignment between this compound and a holetransport material [e.g., N,N -diphenyl-N,N -bis (1-naphthyl)-1,1 -biphenyl-4,4 -diamine (α-NPD)]. Ultraviolet and inverse photoelectron spectroscopy show that freshly evaporated MoO 3 exhibits deep-lying electronic states with an electron affinity (EA) of 6.7 eV and ionization energy (IE) of 9.7 eV. Air exposure reduces EA and IE by ∼1 eV, to 5.5 and 8.6 eV, respectively, but does not affect the hole-injection efficiency, which is confirmed by device studies. Thus, MoO 3 can be applied in low-vacuum environment, which is particularly important for low-cost manufacturing processes. Our findings of the energy-level alignment between MoO 3 and α-NPD also leads to a revised interpretation of the charge-injection mechanism, whereby the hole-injection corresponds to an electron extraction from the organic highest-occupied molecular orbital (HOMO) level via the MoO 3 conduction band. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

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Highly efficient simplified organic light emitting diodes

Cited by 253 publications

References 18 publications

Transition metal oxides as hole-selective contacts in silicon heterojunctions solar cells

Transition metal oxides as hole-selective contacts in silicon heterojunctions solar cells

Transition metal oxides on organic semiconductors

Electronic structure of molybdenum-oxide films and associated charge injection mechanisms in organic devices

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