Barrier Films

Barrier films from Sumitomo Chemical are flexible, transparent and highly resistant to water vapor and oxygen permeation enabling stable flexible OLED displays & lighting to be realized.

Applications

Today, information is required everywhere, and flexible electronics such as organic light emitting devices and organic thin-film solar cells are becoming more important due to their portability and design versatility.

The reactive metals used in these electronic devices are sensitive to water vapor. To avoid deterioration, the devices need to be well protected from water vapour by barrier films.

Sumitomo Chemical is developing a flexible, high barrier property film material that has four to five orders of magnitude better barrier properties compared to conventional packaging grade barrier films.

graph of barrier propeties required for each application Fig 1. Barrier level demanded by applications

Fig 2. Example barrier film under development

Film properties
Barrier properties 10-3 to 10-6 g/m2/day
Temperature tolerance Non curling at 200°C for 30 minutes
Chemical tolerance Withstands 3% KOH for photoresist removal; withstands ITO etchant
Bending tolerance 10-20㎜ diameter without increasing water vapour transmission rate

Features of Barrier Films

The barrier film consists of a transparent polymer base film and barrier layer. The barrier layer has a compositionally controlled nanostructure, which is made by roll to roll processing.

Organic light emitting devices have a simple device structure and high energy efficiency. Organic thin-film solar cells generate electricity without emitting CO2. Flexible barrier films will be used as substrates for these environmentally friendly electronic devices.

The barrier film has achieved 1000 hours of reliable operation under accelerated conditions in OLED device storage tests.

60°C 90%RH < 24h
Plastic substrate only exhibiting
black spot degradation

60°C 90%RH 1000h <
Sumitomo barrier film

Transparent polymer films, including PET (polyethylene terephthalate), PEN (polyethylene naphthalate), and COP (cyclo-olefin polymer), can be chosen according to the required device application.

Base film properties to which barrier can be applied
  Base film properties
PEN PET COP
Thickness μm 100 100 100
Transmittance % 88 91 93
Tg °C 155 110 163
CTE ppm/°C(30-100°C) 11 15 73
Retardation nm(@550nm) > 1000 > 1000 3
WVTR g/m2·day 1.8 6.8 1.0
Chemical resistance alcohol/hydrocarbon/acid/alkali good/good/reasonable/good good/good/reasonable/poor good/poor/good/good

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