Interface electronic structures of organic light-emitting diodes with WO3 interlayer: A study by photoelectron spectroscopy

Son, Min Jung; Kim, Sehun; Kwon, Soonnam; Kim, Jeong Won

doi:10.1016/j.orgel.2009.02.017

Cited by 68 publications

(30 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Combining measurements of the stoichiometry and He-UPS measurements of the work function of WO x leads to the results depicted in Figure 3 Figure 4 vs. the intensity fraction of the oxygen vacancy related signal in the W4f measurements. This intensity fraction is a qualitative measure for the density of oxygen vacancies in WO x [23]. We confirmed this assessment by measuring the BHI signal before and after annealing in air and vacuum (200…”

Section: Chemical Analysis Of Tungsten Oxidesupporting

confidence: 55%

“…The tungsten 4f core level was measured and fitted according to the analysis presented by Bussalotti et al [21] and adjusted by other groups [22,23]. According to this interpretation the 4f orbital signal of tungsten oxide consists of a doublet of the 7/2 and 5/2 spin states with an energy shift of 2.12 eV between the two components of the doublet, an intensity ratio of 0.75 and the same full with at half maximum for both peaks.…”

Section: Photoelectron Spectroscopymentioning

confidence: 99%

See 1 more Smart Citation

Oxygen vacancies in tungsten oxide and their influence on tungsten oxide/silicon heterojunction solar cells

Mews

Korte

Rech

2016

Solar Energy Materials and Solar Cells

135

105

View full text Add to dashboard Cite

Tungsten oxide (WO x ) can be incorporated into amorphous/crystalline silicon heterojunction solar cells as hole contact and for interface modification between p-type amorphous silicon and indium tin oxide. This paper aims at understanding the influence of tungsten oxides properties on silicon heterojunction solar cells. Using in-system photoelectron spectroscopy on thermally evaporated WO x layers, it was verified that WO x with a stoichiometry close to WO 3 features a work function close to 6 eV and is therefore suitable as hole contact on silicon. Additionally the oxygen vacancy concentration in WO x was measured using photoelectron spectroscopy. High oxygen vacancy concentrations in WO x lead to a low band bending in the WO x /silicon-junction. Furthermore solar cells were fabricated using the same WO x , and the band bending in these cells is correlated with their fill factors (FF) and open circuit voltages (V OC ).Combining these results, the following picture arises: Positively charged oxygen vacancies raise the Fermi-level in WO x and reduce the band bending at the WO x /silicon-junction. This, in turn, leads to reduced V OC and FF. Thus, when incorporating WO x into silicon solar cells it is important to minimize the oxygen vacancy density in WO x . Therefore deposition methods, enabling adjustment of the WO x stoichiometry are preferable.

show abstract

Section: Chemical Analysis Of Tungsten Oxidesupporting

confidence: 55%

Section: Photoelectron Spectroscopymentioning

confidence: 99%

Oxygen vacancies in tungsten oxide and their influence on tungsten oxide/silicon heterojunction solar cells

Mews

Korte

Rech

2016

Solar Energy Materials and Solar Cells

135

105

View full text Add to dashboard Cite

show abstract

“…Deconvolution of the spectrum demonstrates two distinct contributions: The W 6+ doublet as found before and a minor doublet with weight ratio 4:3, width of 1.8 eV, and lower binding energies of 34.7 eV for W 4 f 7/2 and 36.8 eV for W 4 f 5/2 . The new doublet represents W +5 ions2324, which trace back to the presence of O vacancies.…”

Section: Resultsmentioning

confidence: 99%

Intrinsic Defects and H Doping in WO3

Zhu

Vasilopoulou

Davazoglou

et al. 2017

Sci Rep

View full text Add to dashboard Cite

WO3 is widely used as industrial catalyst. Intrinsic and/or extrinsic defects can tune the electronic properties and extend applications to gas sensors and optoelectonics. However, H doping is a challenge to WO3, the relevant mechanisms being hardly understood. In this context, we investigate intrinsic defects and H doping by density functional theory and experiments. Formation energies are calculated to determine the lowest energy defect states. O vacancies turn out to be stable in O-poor environment, in agreement with X-ray photoelectron spectroscopy, and O-H bond formation of H interstitial defects is predicted and confirmed by Fourier transform infrared spectroscopy.

show abstract

“…2(a). The binding energy of W 4f 7/2 of the new doublet is at 34.8 eV and is attributed to the presence of W 5 þ atoms in WO 3 À x [18]. The relative atomic concentrations in the analyzed region were calculated by dividing the total peak area of W 4f and O 1s (not shown here).…”

Section: Resultsmentioning

confidence: 99%

Omnidirectional antireflective properties of porous tungsten oxide films with in-depth variation of void fraction and stoichiometry

Vourdas

Dalamagkidis

Kostis

et al. 2012

Optics Communications

View full text Add to dashboard Cite

a b s t r a c tWe report on the fabrication of porous hot-wire deposited WO x (hwWO x ) films with omnidirectional antireflective properties coming from in-depth variation of both (i) void fraction from 0% at the Si substrate/hwWO x interface to 30% within less than 7 nm and to higher than 50% at the hwWO x /air interface, and (ii) x, namely hwWO x stoichiometry, from 2.5 at the Si/hwWO x to 3 within less than 7 nm. hwWO x films were deposited by means of hw deposition at rough vacuum and controlled chamber environment. The films were analyzed by Spectroscopic Ellipsometry to extract the graded refractive index profile, which was then used in a rigorous coupled wave analysis (RCWA) model to simulate the antireflective properties. RCWA followed reasonably the experimental reflection measurements. Void fraction and x in-depth variation, controlled by the hw process, greatly affect the antireflective properties, and improve the omnidirectional and broadband characteristics. The reflection suppression below 10% within the range of 500-1000 nm for angles of incidence up to more than 601 is demonstrated.

show abstract

Interface electronic structures of organic light-emitting diodes with WO3 interlayer: A study by photoelectron spectroscopy

Cited by 68 publications

References 21 publications

Oxygen vacancies in tungsten oxide and their influence on tungsten oxide/silicon heterojunction solar cells

Oxygen vacancies in tungsten oxide and their influence on tungsten oxide/silicon heterojunction solar cells

Intrinsic Defects and H Doping in WO3

Omnidirectional antireflective properties of porous tungsten oxide films with in-depth variation of void fraction and stoichiometry

Contact Info

Product

Resources

About