Effect of stoichiometry and microstructure on hydrolysis in MoO3 films

Sian, Tarsame S.; Reddy, G. B.

doi:10.1016/j.cplett.2005.10.112

Cited by 11 publications

(16 citation statements)

References 10 publications

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“…The widening of the region below 400 nm corresponds to the ZnO and MoO 3 absorption region. 60 The latter indicates that the ambient atmosphere is modifying the properties of these oxides, in agreement with the sensitivity towards humidity known for several semiconductor oxides, 47,50 among which are MoO 3 49,51 and ZnO. 48 The shift observed for the maximum IPCE peak shown in Fig.…”

Section: Un-encapsulated Devices: Nrel and Imecsupporting

confidence: 82%

“…44 It has also been related to the formation of pinholes and the catastrophic failure of J sc observed in inverted OPVs analyzed in air leading to the reduction of device lifetime. 45,46 Although semiconductor oxides like ZnO or MoO 3 are also known to be sensitive to moisture, [47][48][49][50][51] the MoO 3 layer has shown to be much more stable to humidity than the PEDOT polymer [44][45][46]52,53 and reports on the improvement of device lifetime can already be found in the literature when the MoO 3 layer is used instead of PEDOT:PSS. 54 All the aforementioned detrimental effects on OPVs observed when PEDOT:PSS is applied have also been observed for the NREL devices analyzed in this collaborative work as already reported.…”

Section: Un-encapsulated Devices: Nrel and Imecmentioning

confidence: 99%

“…54 Although the hygroscopic PEDOT:PSS is known to be catastrophic for organic solar cells, [44][45][46] we should keep in mind that semiconductor oxides like ZnO and MoO 3 can also be sensitive to moisture. [47][48][49][50][51] In fact, semiconductor oxides are used as humidity sensors 50,51 and thus the ambient atmosphere also exerts an important effect on the IMEC devices. In general, most of the features observed for the NREL devices were observed for the IMEC devices.…”

Section: Un-encapsulated Devices: Nrel and Imecmentioning

confidence: 99%

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On the stability of a variety of organic photovoltaic devices by IPCE and in situ IPCE analyses – the ISOS-3 inter-laboratory collaboration

Terán-Escobar

Tanenbaum

Voroshazi

et al. 2012

Phys. Chem. Chem. Phys.

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This work is part of the inter-laboratory collaboration to study the stability of seven distinct sets of state-of-the-art organic photovoltaic (OPV) devices prepared by leading research laboratories. All devices have been shipped to and degraded at RISØ-DTU up to 1830 hours in accordance with established ISOS-3 protocols under defined illumination conditions. In this work, we apply the Incident Photon-to-Electron Conversion Efficiency (IPCE) and the in situ IPCE techniques to determine the relation between solar cell performance and solar cell stability. Different ageing conditions were considered: accelerated full sun simulation, low level indoor fluorescent lighting and dark storage. The devices were also monitored under conditions of ambient and inert (N 2 ) atmospheres, which allows for the identification of the solar cell materials more susceptible to degradation by ambient air (oxygen and moisture). The different OPVs configurations permitted the study of the intrinsic stability of the devices depending on: two different ITO-replacement alternatives, two different hole extraction layers (PEDOT:PSS and MoO 3 ), and two different P3HT-based polymers. The response of un-encapsulated devices to ambient atmosphere offered insight into the importance of moisture in solar cell performance. Our results demonstrate that the IPCE and the in situ IPCE techniques are valuable analytical methods to understand device degradation and solar cell lifetime.

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Section: Un-encapsulated Devices: Nrel and Imecsupporting

confidence: 82%

Section: Un-encapsulated Devices: Nrel and Imecmentioning

confidence: 99%

Section: Un-encapsulated Devices: Nrel and Imecmentioning

confidence: 99%

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On the stability of a variety of organic photovoltaic devices by IPCE and in situ IPCE analyses – the ISOS-3 inter-laboratory collaboration

Terán-Escobar

Tanenbaum

Voroshazi

et al. 2012

Phys. Chem. Chem. Phys.

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“…These observations are consistent with the findings of Reddy et al [54] who studied MoO x films of different microstructures and stoichiometries exposed to ambient air humidity, by infrared spectroscopy. They reported that amorphous, nearly stoichiometric MoO x films (x&3) contain the largest amount of hydrolyzed Mo-OH bonds.…”

Section: Stability Of Moo X Layers and Dmd Electrodessupporting

confidence: 92%

“…This is explained by the acid-base mechanism, where the electron lone pairs of OH -(arising from H 2 O dissociation) must be transferred to the 4d vacant orbitals of Mo. In nonstoichiometric films, 4d orbitals are partially filled, impeding the electron transfer, i.e., the growth of hydrolyzed bonds is slowed down [54]. Interestingly, highly stoichiometric but polycrystalline films did not show hydrolyzed bonds.…”

Section: Stability Of Moo X Layers and Dmd Electrodesmentioning

confidence: 99%

Fast sputter deposition of MoOx/metal/MoOx transparent electrodes on glass and PET substrates

et al. 2021

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Dielectric/metal/dielectric (DMD) transparent electrodes emerged as a compelling alternative to the widely used indium-tin-oxide (ITO) for solar cells and optoelectronic devices. DMD electrodes are especially attractive for flexible substrates, as, in contrast to ITO, they retain their low electrical resistance upon substrate bending and they do not require deposition at elevated temperatures. In a DMD, the choice of the dielectric is mainly dictated by the device architecture. Owing to its high work function, MoO 3 is a commonly used hole-selective dielectric layer. The present work investigates MoO x /metal/MoO x (with 2 \ x \ 3) DMD electrodes, with Ag and Au as metals, fabricated by direct current, magnetron sputtering, at industry-relevant, high deposition rates. This was possible with a properly engineered MoO x target, providing high electrical conductivity and compactness. The sputtered electrodes on polyethylene terephthalate (PET) substrates show higher figure-of-merit than similar, evaporated electrodes in the literature. It is shown that the DMD electrodes with amorphous MoO x layers have low stability in water, but they are stable to other solvents, such as toluene, dimethylsulfoxide (DMSO), dimethylformamide (DMF), chlorobenzene or chloroform, allowing their implementation in devices like organic light-emitting diodes or perovskite solar cells. Further, it is shown that the electrodes show dramatically enhanced mechanical stability compared to ITO, when subjected to tensile bending tests.

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