5: a) Schematic structure of a typical organic solar cell showing a glass or PET: Polyethylene terephthalate (substrate), Indium tin oxide: ITO (bottom electrode), ZnO: Zinc oxide (electron extraction layer), blend of P3HT:PCBM (active layer), PEDOT:PSS: Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (hole extraction layer) and Silver:Ag (top electrode) b) Energy band diagram of a normal cell structure and c) Energy band diagram of an inverted cell structure. Data extracted from [69].

Contexts in source publication

Context 1

... water vapor transmission rate it is usually given in mass units ( and pressure. í µí±ƒ í µí°» í µí°» 2 í µí±‚ (T) denotes the saturation partial pressure of water at the given temperature T (Figure 2.1) and ∆í µí±Ÿℎ denotes the difference of relative humidity across the barrier. ...

Context 2

... relation is illustrated in Figure 2.2(a, c), where the permeation (WVTR and OTR) dependence of biaxially oriented polypropylene (BOPP) and biaxially oriented polyvinyl alcohol (BOPVA) on temperature are shown [31]. ...

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... should be noted that permeation of gases is generally affected by the presence of other gases. Figure 2.2 (b,d) shows the dependence of permeation of oxygen and water on relative humidity for BOPP and BOPVA membranes. ...

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... tortuosity factor í µí¼ depends on several geometrical parameters such as the volume fraction of nanofillers Φ, their aspect ratio í µí»¼ and the aspect ratio of pores and slits across adjacent fillers in the similar horizontal plane σ. To define these parameters, we first consider a repeating unit cell as seen in Figure 2.3(ii), where each of the rectangular plates, representing the filler particles with dimensions w, t, and l, is filled into one of the polymer unit cells, having finite width W, thickness T and length L [45], [46]. ...

Context 5

... of the models in literature developed earlier describing diffusion in a composite material are based on 2D systems in which the filler particles have a rectangular shape, resembling ribbons of infinite length with a finite width (w) and thickness (t) [47]. These models assume that the fillers are arranged regularly in the polymer matrix and perpendicularly with respect to the diffusion direction, as can be seen in Figure 2.3. Some of these models are presented in Table 1. ...

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... Nielsen [48] proposed a simple permeability model (Eq. 23) for such a system which is based on the idea that diffusing molecules need to pass by a longer path in order to exit the film as seen in Figure 2.3. This model is widely used but is only applicable in the dilute regime (í µí»¼Φ ≪ 1). ...

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... µí»¼ = í µí±Ží µí± í µí±í µí±’í µí±í µí±¡ í µí±Ÿí µí±Ží µí±¡í µí±–í µí±œ, í µí»· = í µí±£í µí±œí µí±™í µí±¢í µí±ší µí±’ í µí±“í µí±Ÿí µí±Ží µí±í µí±¡í µí±–í µí±œí µí±› í µí±œí µí±“ í µí±¡ℎí µí±’ í µí±“í µí±–í µí±™í µí±™í µí±’í µí±Ÿ, í µí¼Ž = í µí±Ží µí± í µí±í µí±’í µí±í µí±¡ í µí±Ÿí µí±Ží µí±¡í µí±–í µí±œ í µí±œí µí±“ í µí±¡ℎí µí±’ í µí± í µí±™í µí±–í µí±¡í µí± . where x and l are represented in Figure 2.3. This parameter takes into account the deviation from ideally positioned flakes by expressing the horizontal offset of each particle with regard to the one below it [55]. ...

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... shown in Figure 2.5, a typical organic solar cell has two electrodes, at least one of which is semitransparent. This permits light radiations to interact with active layer. ...

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... the characterization of a solar cell, current density-voltage (J-V) curves are measured under illumination. The jV-curve can be obtained by treating the solar cell in terms of the so called one diode model, which corresponds to the equivalent circuit described in Figure 2.6. From a typical curve, the useful information is extracted in terms of power conversion efficiency (PCE), short circuit current density (Jsc), open circuit current (Voc) and fill factor (FF). ...

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... compared to materials used in inorganic solar cells, most organic matter utilized in organic solar cells, have the susceptibility to degrade chemically by oxygen, moisture and ultraviolet rays interactions (as shown in Figure 2.7) [6], [78]- [80]. ...

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... to Eq. 16 a possible strategy of decreasing the permeability consists in increasing the path that permeant molecules have to follow through the coating in order to reach the other side of the membrane [110], [111]. The addition of obstacles ( Figure 2.3) is thought to create a tortuous path for diffusing molecules [45], [65]. ...

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... roughness or agglomeration of the clay particles at the surface or within the film can cause scattering of the light. In this case, the increase in haze is associated to surface roughness, as the layer with 6 vol% clay shows a relatively rough surface as compared to layers with low concentration clay ( Figure 5.2 Figure 5.4 and subsequent values are mentioned in Table 9. The increase in thickness creates longer paths and moisture molecule take longer time to diffuse from one side to another, hence moisture permeation is decreased. ...

Context 13

... trend of conversion of the PHPS is nearly as same as that of deep UV cured but the barrier behavior is slightly different. However, the shape of the spectra is slightly different as compared to deep UV with much more sharp peak at 1050 cm -1 ( Figure 5.29a). In the case of damp heat, lowest permeation is obtained with exposure time of 300 minutes which is 0.09 g/m 2 .day ...