Abstract
Description
The biggest opportunity for OLED displays and organic photovoltaics is when
these devices can be flexible, allowing them to be more robust, versatile and
made in large areas compared to conventional displays and photovoltaics.
However, many of the materials used in OLED displays and organic photovoltaics
are sensitive to the environment, limiting their lifetime. These materials can
be protected using substrates and barriers such as glass and metal, but this
results in a rigid device and does not satisfy the applications demanding
flexible devices. Plastic substrates and transparent flexible encapsulation
barriers can be used, but these offer little protection to oxygen and water,
resulting in the devices rapidly degrading.
In order to achieve device lifetimes of tens of thousands of hours, water
vapor transmission rates (WVTR) must be 10-6 g/m2/day, and oxygen transmission
rates (OTR) must be < 10-3 cm3/m2/day. For Organic Photovoltaics, the
required WVTR is not as stringent as OLEDs require but is still very high at a
level of 10-5 g/m2/day. These transmission rates are several orders of
magnitude smaller than what is possible using any plastic substrate, and they
can also be several orders of magnitude smaller than what can be measured
using common equipment (MOCON) designed for this purpose (Table 1). For these
(and other) reasons, there has been intense interest in developing transparent
barrier materials with much lower permeabilities.
This concise and unique report from IDTechEx gives an in-depth review to the
needs, emerging solutions and players. It addresses specific topics such as:
- Companies which are active in the development of high barrier films and
their achievements on the field to date.
- Surface smoothness and defects (such as cracks and pinholes) and the
effect that these characteristics would have on the barrier behavior of the
materials studied.
- Traditional methods of measurement of permeability are reaching the end of
their abilities. The MOCON WVTR measurement device, which has been an industry
standard, cannot give adequate measurements at the low levels of permeability
required for Organic Photovoltaics and OLEDs. Other methods of measurement and
equipment developed are being discussed.
- Forecasts for OLEDs and OPV, in order to understand the influence that the
development of flexible barriers would have at the mass deployment and
adoption of these technologies.
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