Oligothiophene films under electron irradiation: electron mobility and contact potentials

Pellegrino, Olivier; Vilar, M. Rei; Horowitz, Gilles; Rego, A.M. Botelho do

doi:10.1016/s0928-4931(02)00207-2

Cited by 17 publications

(8 citation statements)

References 27 publications

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“…Therefore, the work function values of 4.66 eV for ZnS and 4.58 eV for Si͑111͒ can be deduced by assuming 4.60 eV for HOPG. 22 The smaller absolute value of the compensated voltage for ZnS than that for Si͑111͒, consistent with the darker features appeared in Fig. 2͑b͒, indicates smaller electrostatic force interactions.…”

supporting

confidence: 65%

Improving lateral resolution of electrostatic force microscopy by multifrequency method under ambient conditions

Ding

et al. 2009

Applied Physics Letters

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supporting

confidence: 65%

Improving lateral resolution of electrostatic force microscopy by multifrequency method under ambient conditions

Ding

et al. 2009

Applied Physics Letters

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“…The measurements of the surface potential were done with a McAllister KP6500 Kelvin‐Probe (KP) system under controlled atmosphere (vacuum (10 −6 mbar), pure oxygen, air). Highly ordered pyrolytic graphite with a WF of 4.5 eV was used as reference …”

Section: Methodsmentioning

confidence: 99%

Avoiding Photoinduced Shunts in Organic Solar Cells by the Use of Tin Oxide (SnO_x) as Electron Extraction Material Instead of ZnO

Trost

Becker

Polywka

et al. 2016

Advanced Energy Materials

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low fi ll-factors (FFs) and overall low power conversion efficiency are found. This phenomenon is frequently referred to as "light-soaking" issue. [ 31,32 ] Development of charge extraction materials that do not rely on UV activation has been identifi ed to be of paramount importance to achieve highly effi cient and long-term stable devices. [ 33,34 ] In this sense, doped metaloxide EELs, e.g., Al:ZnO, [ 31,35,36 ] have been shown to mitigate the need for UV activation. While there are several reports of OSCs incorporating ZnO-based EELs in organic solar cells, which show a promising "shelf-life," [ 37 ] photoinduced shunts have been found to occur in the devices upon illumination "in actual operation." [38][39][40] Analogous to the case of the light activation discussed above, these photoinduced shunts are associated with the illumination by UV light (i.e., hν > E g ). As a result, a signifi cantly lowered shunt resistance along with a substantial decay of the FF and V oc is typically found to occur within minutes of illumination. The origin of this photoinduced shunt has been related to the UV-induced desorption of chemisorbed oxygen at the ZnO surface. [ 38 ] Approaches to modify and thereby to stabilize the ZnO surface range from the use of passivating mole cules [ 41 ] to the evaporation of thin aluminum layers onto the ZnO EEL. [ 39 ] Here, we will show that the photoinduced shunting behavior is a general phenomenon in OSCs comprising "neat or electrically doped" ZnO-based electron extraction layers, i.e., Al:ZnO (AZO) or Ga:ZnO (GZO), and it is found regardless if the EEL is prepared from nanoparticle dispersions or by vacuumbased techniques ( Figure 1 ). The photoinduced shunting of ZnO-based OSCs occurs for devices operated in air or under inert atmosphere, and it can therefore not be avoided by using a proper encapsulation. Moreover, we will show that while the photoinduced shunting is reversible in air, it is irreversible under the exclusion of oxygen. Opposed to ZnO-based EELs, we will demonstrate that the photoinduced shunting and the con-

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“…The measurements of the surface potential were done with a McAllister KP6500 Kelvin-Probe (KP) system in ambient air or under controlled atmosphere (vacuum, pure oxygen). Highly ordered pyrolytic graphite with a WF of 4.5 eV was used as reference 70 71 .…”

Section: Methodsmentioning

confidence: 99%

Plasmonically sensitized metal-oxide electron extraction layers for organic solar cells

Trost

Becker

Zilberberg

et al. 2015

Sci Rep

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ZnO and TiOx are commonly used as electron extraction layers (EELs) in organic solar cells (OSCs). A general phenomenon of OSCs incorporating these metal-oxides is the requirement to illuminate the devices with UV light in order to improve device characteristics. This may cause severe problems if UV to VIS down-conversion is applied or if the UV spectral range (λ < 400 nm) is blocked to achieve an improved device lifetime. In this work, silver nanoparticles (AgNP) are used to plasmonically sensitize metal-oxide based EELs in the vicinity (1–20 nm) of the metal-oxide/organic interface. We evidence that plasmonically sensitized metal-oxide layers facilitate electron extraction and afford well-behaved highly efficient OSCs, even without the typical requirement of UV exposure. It is shown that in the plasmonically sensitized metal-oxides the illumination with visible light lowers the WF due to desorption of previously ionosorbed oxygen, in analogy to the process found in neat metal oxides upon UV exposure, only. As underlying mechanism the transfer of hot holes from the metal to the oxide upon illumination with hν < Eg is verified. The general applicability of this concept to most common metal-oxides (e.g. TiOx and ZnO) in combination with different photoactive organic materials is demonstrated.

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Oligothiophene films under electron irradiation: electron mobility and contact potentials

Cited by 17 publications

References 27 publications

Improving lateral resolution of electrostatic force microscopy by multifrequency method under ambient conditions

Improving lateral resolution of electrostatic force microscopy by multifrequency method under ambient conditions

Avoiding Photoinduced Shunts in Organic Solar Cells by the Use of Tin Oxide (SnO_x) as Electron Extraction Material Instead of ZnO

Plasmonically sensitized metal-oxide electron extraction layers for organic solar cells

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Oligothiophene films under electron irradiation: electron mobility and contact potentials

Cited by 17 publications

References 27 publications

Improving lateral resolution of electrostatic force microscopy by multifrequency method under ambient conditions

Improving lateral resolution of electrostatic force microscopy by multifrequency method under ambient conditions

Avoiding Photoinduced Shunts in Organic Solar Cells by the Use of Tin Oxide (SnOx) as Electron Extraction Material Instead of ZnO

Plasmonically sensitized metal-oxide electron extraction layers for organic solar cells

Contact Info

Product

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Avoiding Photoinduced Shunts in Organic Solar Cells by the Use of Tin Oxide (SnO_x) as Electron Extraction Material Instead of ZnO