Process development and accurate low‐cost characterization for OLED sealants by using a calcium test

Hergert, Steffen; Linkor, Max; Korny, Markus; Fruehauf, Norbert

doi:10.1889/1.2749328

Cited by 6 publications

(6 citation statements)

References 4 publications

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“…The UHPBFs have proven to be a suitable option for the encapsulation of optoelectronic devices because of their low WVTR values. Generally, the UHPBFs are commercialized indicating “extrinsic” WVTRs which include all defects on a certain large‐area (i.e., 70 cm 2 ) as measured with the Wasserdampf‐Durchlässigkeits (WDDG) water vapour permeability coulometric testers or on small‐area (i.e., 3 mm diameter) with, for example, the Ca‐Test . According to the international standards such as to ISO 15106‐3:2003 standard and BS3177, the extrinsic WVTR is measured after the barrier fabrication at 38 °C and 90% RH.…”

Section: Resultsmentioning

confidence: 99%

“…The results of optical (change in area including deposition defects) and electrical (change in conductance) Ca‐test were plotted as a function of time, and the resulting curves were fitted with the quick fit tool of Origin from OriginLab Company. Fitting was performed on the linear part of the curve and the calculated slope corresponded to the terms d( A )/d t or d(1/ R )/d t of Equations and respectively.

{WVTR}_{O} = - 2 (\frac{M_{H_{2} O}}{M_{Ca}}) \frac{δ d}{A_{o}} \frac{d (A)}{d t}

{WVTR}_{E} = - 2 (\frac{M_{H_{2} O}}{M_{Ca}}) δ ρ (l / b) \frac{d (1 / R)}{d t}

where A, R, δ, ρ, d, A 0 , l , and b are the area, resistance, density, resistivity, thickness, initial area, initial length, and initial width of calcium sensor, and M H2O and M Ca are the molecular weights of water and calcium.…”

Section: Methodsmentioning

confidence: 99%

“…Different stacks of flexible barriers have been developed using Al, Al 2 O 3 , SiO x , SiN, TiO 2 , Zn 2 SnO 4 , and/or organic‐inorganic hybrid polymer layers, and some remarkable WVTRs have been obtained (<1 × 10 −5 g m −2 d −1 ) . Although the WVTR of the multilayer barrier is measured, inter alia, by gravimetric, coulometric, electrical, or optical methods, the performance of the complex barrier/adhesive system can vary when applied on a device because the latter comprises more than one material layer, the sealant/adhesive can affect the underlying layers differently and some moisture/oxygen can be incorporated during device preparation as well as through the adhesive. Additionally, the most sensitive materials are also affected/degraded by other external agents such as light, temperature, internal chemical reactions occurring between layers, or ion migration .…”

Section: Introductionmentioning

confidence: 99%

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Quantifying Performance of Permeation Barrier—Encapsulation Systems for Flexible and Glass‐Based Electronics and Their Application to Perovskite Solar Cells

Castro‐Hermosa

Top

Dagar

et al. 2019

Adv Elect Materials

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markets for the more mature technologies, and research for the emerging technologies, are increasing year by year. Among these are organic, metal oxide, and organo-hybrid perovskite semiconductor transistor, light-emitting diode, and solar cell-based systems. [1][2][3][4] Large-area optoelectronics is developed on rigid (mainly on glass) and flexible (mainly on plastic such as polyethylene terephthalate, PET) substrates [5] with other types of substrates also being investigated such as paper, [6,7] flexible glass, [8] or textiles. [9] Organic lightemitting diodes (OLEDs), for example, are today one of the most commercialized technologies especially in small-display markets (e.g., smartphone displays) where they now take a major share of the market. In research laboratories, perovskite solar cells (PSC) have seen a huge interest reaching certified record efficiencies of 25.2% at standard test conditions (Air mass AM1.5G, 1000 W m −2 , 25 °C) [10] within only 10 years of development. Further they reach the highest power output densities under artificial indoor illumination (i.e., 20.2 µW cm −2 at 200 lx [11] ) which make them not only a bright candidate for energy harvesting outdoors but also for indoor IoT devices, sensors, and small consumer electronics [12] even for flexible substrates under artificial lighting. [13,14] The success of large area electronics in general lies in the advantageous properties of the materials used and in the fabrication processes (e.g., evaporation, sputtering or solution processing via printing techniques). These are also often compatible with flexible substrates. [15,16] Nevertheless, lifetimes of many of the constituent materials suffer when coming in contact with ambient moisture and oxygen [17][18][19] which can induce chemical degradation to the semiconducting, transport, and electrode layers. [20][21][22] To avoid moisture and oxygen ingress and further degradation, devices must be encapsulated with permeation barriers ensuring a water vapor transmission rate (WVTR) range of 10 −3 to 10 −6 g m −2 d −1 [23][24][25][26][27][28] and an oxygen transmission rate (OTR) between 10 −2 and 10 −5 cm 3 m −2 d −1 . [29][30][31][32] Encapsulation Effective transparent barrier/encapsulation systems represent a key enabling technology for large-area electronics. Securing stability to the environment is vital. Here, the effects of architectures, application processes, and water vapor transmission rates (WVTR) of transparent flexible ultra-high permeation barrier films (UHPBF) applied to substrates with adhesive resins are unraveled for attaining long lifetime, and compared with polyethylene terephthalate and glass barriers. How strongly performance of barrier/adhesive systems depends on barrier orientation, adhesion, manipulation, defects, and storage procedures is quantified via calcium tests. Furthermore, it is found that introducing an additional adhesion-promoting layer on the standard UHPBF stack reduces WVTRs by a factor of 5 compared to barriers without it. Finally, barriers are used fo...

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Section: Resultsmentioning

confidence: 99%

{WVTR}_{O} = - 2 (\frac{M_{H_{2} O}}{M_{Ca}}) \frac{δ d}{A_{o}} \frac{d (A)}{d t}

{WVTR}_{E} = - 2 (\frac{M_{H_{2} O}}{M_{Ca}}) δ ρ (l / b) \frac{d (1 / R)}{d t}

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Quantifying Performance of Permeation Barrier—Encapsulation Systems for Flexible and Glass‐Based Electronics and Their Application to Perovskite Solar Cells

Castro‐Hermosa

Top

Dagar

et al. 2019

Adv Elect Materials

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“…The UHB stack used for this study consists of a three‐layer stack (PET substrate/ZTO 160 nm/ORMOCER ® 1 μm/ZTO 160 nm) shown in Figure , having a water vapor transmission rate of (1.6±0.5)×10 −4 g m −2 d −1 ) at 38 °C/90 % relative humidity, measured with an optical calcium test according to the setup described in Ref. .…”

Section: Resultsmentioning

confidence: 99%

A Systematic Investigation of Permeation Barriers for Flexible Dye‐Sensitized Solar Cells

et al. 2016

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Dye solar cells (DSCs), in their flexible form, are prone to ageing due to ingress of gas as a result of the intrinsic permeability of polymer substrates. Thus, it is important to develop proper encapsulation strategies to limit degradation. Literature on flexible DSCs lacks comparative tests with different permeation barriers, including flexible ultrahigh barriers (UHB). We designed such tests and applied UHBs to flexible DSCs for the first time. We demonstrate that UHBs double the lifetime of cells with respect to those with none or less‐effective barriers. Degradation is due to a combination of electrolyte bleaching, dye detachment, and indium tin oxide (ITO) degradation. The reduced, though still noticeable, performance loss for UHB‐ and glass‐equipped cells can be mainly ascribed to lateral permeation of gas/water, suggesting that efficient solutions for edge encapsulation must be developed to extend lifetimes further.

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“…The measurement area was 78 cm². All samples with water vapor permeability below the detection limit of the device were characterized in an optical Calcium-Test measurement according to the setup described by Hergert et al [14]. Thereby a photodiode was used as detector for the optical transmission of the calcium layer.…”

Section: Characterization Methodsmentioning

confidence: 99%

10.1: Invited Paper: Roll‐to‐Roll Manufacturing of Functional Substrates and Encapsulation Films for Organic Electronics: Technologies and Challenges

Fahlteich

Steiner

Top

et al. 2015

Symp Digest of Tech Papers

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This paper reviews a roll-to-roll technology for manufacturing of functional films as substrates and encapsulation for flexible OLED display and lighting devices. These functional films comprise ultra-high permeation barrier performance and two different types of a transparent electrode. Flexible small molecule OLED devices have been manufactured in roll-to-roll and characterized discussing current challenges for flexible electronic device encapsulation.

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Process development and accurate low‐cost characterization for OLED sealants by using a calcium test

Cited by 6 publications

References 4 publications

Quantifying Performance of Permeation Barrier—Encapsulation Systems for Flexible and Glass‐Based Electronics and Their Application to Perovskite Solar Cells

Quantifying Performance of Permeation Barrier—Encapsulation Systems for Flexible and Glass‐Based Electronics and Their Application to Perovskite Solar Cells

A Systematic Investigation of Permeation Barriers for Flexible Dye‐Sensitized Solar Cells

10.1: Invited Paper: Roll‐to‐Roll Manufacturing of Functional Substrates and Encapsulation Films for Organic Electronics: Technologies and Challenges

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