The effect of barrier performance on the lifetime of small-molecule organic solar cells

Hermenau, Martin; Schubert, Sylvio; Klumbies, Hannes; Fahlteich, John; Müller‐Meskamp, Lars; Leo, Karl; Riede, Moritz

doi:10.1016/j.solmat.2011.09.026

Cited by 64 publications

(39 citation statements)

References 23 publications

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“…4 to grow over time consistent with previous reports [7,8,10,11]. In contrast to these reports and in agreement with others [6,[12][13][14], we observe that the impact of degradation at pinholes is less important, compared with degradation at the edges of the device. This is consistent with the observations of Voroshazi et al [6], in which the contaminant is identified as water.…”

Section: General Observations In Non-encapsulated Devicessupporting

confidence: 92%

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Spatially resolved photocurrent measurements of organic solar cells: Tracking water ingress at edges and pinholes

Feron

Nagle

Rozanski

et al. 2013

Solar Energy Materials and Solar Cells

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Section: General Observations In Non-encapsulated Devicessupporting

confidence: 92%

“…Conversely, we find that edges appear to be the principal pathway for ingress. Others have also observed this, especially for small-area devices [6,[12][13][14]. Voroshazi et al [6] concluded that the impact of the perimeter:area ratio of the device affects the device lifetime.…”

Section: Introductionmentioning

confidence: 90%

Spatially resolved photocurrent measurements of organic solar cells: Tracking water ingress at edges and pinholes

Feron

Nagle

Rozanski

et al. 2013

Solar Energy Materials and Solar Cells

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“…[15][16][17] We investigate the influence of doping concentration on the operation voltage and efficiency of red and green phosphorescent OLEDs. We find that BF-DPB and NPB based OLEDs exhibit significantly steeper J-V curves than devices based on the other two HTLs and thus achieve excellent luminous efficacy.…”

Section: -14mentioning

confidence: 99%

Alternative p-doped hole transport material for low operating voltage and high efficiency organic light-emitting diodes

Murawski

Fuchs

Hofmann

et al. 2014

Applied Physics Letters

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We investigate the properties of N,N′-[(Diphenyl-N,N′-bis)9,9,-dimethyl-fluoren-2-yl]-benzidine (BF-DPB) as hole transport material (HTL) in organic light-emitting diodes (OLEDs) and compare BF-DPB to the commonly used HTLs N,N,N′,N′-tetrakis(4-methoxyphenyl)-benzidine (MeO-TPD), 2,2′,7,7′-tetrakis(N,N′-di-p-methylphenylamino)-9,9′-spirobifluorene (Spiro-TTB), and N,N′-di(naphtalene-1-yl)-N,N′-diphenylbenzidine (NPB). The influence of 2,2′-(perfluoronaphthalene-2,6-diylidene)dimalononitrile (F6-TCNNQ p-dopant) concentration in BF-DPB on the operation voltage and efficiency of red and green phosphorescent OLEDs is studied; best results are achieved at 4 wt. % doping. Without any light extraction structure, BF-DPB based red (green) OLEDs achieve a luminous efficacy of 35 .1 lm/W (74 .0 lm/W) at 1000 cd/m2 and reach a very high brightness of 10 000 cd/m2 at a very low voltage of 3.2 V (3.1 V). We attribute this exceptionally low driving voltage to the high ionization potential of BF-DPB which enables more efficient hole injection from BF-DPB to the adjacent electron blocking layer. The high efficiency and low driving voltage lead to a significantly lower luminous efficacy roll-off compared to the other compounds and render BF-DPB an excellent HTL material for highly efficient OLEDs.

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“…[ 8,19,37,38 ] To overcome this problem, high barrier encapsulation materials with water vapor transmission rates (WVTRs) much lower than ≈10 −3 g (m 2 day) −1 are commonly used in order to achieve module lifetimes of several thousands of hours. [39][40][41] Conversely, the implementation of inverted device geometries in OPVs allows the use of noble metals such as gold and silver, thereby extending the effective life span of photovoltaic devices. [ 34 ] In this case, the device lifetime could be dictated by the diffusion of water or by photo-oxidation, depending on the degradation kinetics of the system.…”

Section: Introductionmentioning

confidence: 99%

Water Ingress in Encapsulated Inverted Organic Solar Cells: Correlating Infrared Imaging and Photovoltaic Performance

Adams

Salvador

Lucera

et al. 2015

Advanced Energy Materials

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Understanding the degradation and failure mechanisms of organic photovoltaic devices is a key requirement for this technology to mature toward a reliable product. Here, an investigation on accelerated temperature and moisture long‐term stability testing (>20 000 h) of inverted and glass‐encapsulated poly(3‐hexylthiophene)/phenyl‐C61‐butyric acid methyl ester solar cells is presented. The degradation kinetics is analyzed using the Arrhenius model and the resulting activation energy for the diffusion of water is measured to be ≈43 kJ mol−1. Through comparison of electroluminescence imaging, lock‐in thermography, and photoluminescence mapping, the device performance is correlated with the loss of effective cell area and it is shown that the reaction of water at the hole extraction/active layer interface is likely to be the dominant cause for long‐term device failure. The diffusion of water through the packaged solar cell is described using classical diffusion theory. Based on an analytical solution of a simple diffusion model, the diffusion coefficient is estimated to be 4 × 10−12 m2 s−1. A shelf life of 100 000 h is anticipated at 65 °C/85% RH using a 9.3 cm wide protective adhesive rim. The findings of this study may inform strategies for predicting lifetimes of organic solar cells and modules based on local in situ tracking of moisture‐induced device performance loss using IR imaging.

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The effect of barrier performance on the lifetime of small-molecule organic solar cells

Cited by 64 publications

References 23 publications

Spatially resolved photocurrent measurements of organic solar cells: Tracking water ingress at edges and pinholes

Spatially resolved photocurrent measurements of organic solar cells: Tracking water ingress at edges and pinholes

Alternative p-doped hole transport material for low operating voltage and high efficiency organic light-emitting diodes

Water Ingress in Encapsulated Inverted Organic Solar Cells: Correlating Infrared Imaging and Photovoltaic Performance

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