Moisture barriers serve as a robust packaging solution to enclose moisture sensitive encapsulated materials. They enable a device, product, substrate, or apparatus which in use will be exposed to moisture, water vapor, freeze thaw cycles or other environmental elements that could compromise the longevity or integrity of the device or product. For example, a photovoltaic cell must able to withstand long durations of rain, snow, fog, dew, environmental contaminants or other substances. The encapsulated material may be, but is not limited to, a semiconductor device such as a photovoltaic cell, integrated circuit device, photonic devices, batteries, sensors, actuators, flat panel displays, food, and pharmaceuticals. The growth in PV installations has brought heightened awareness on the quality of materials and installations. Most panels come with a 20-year warranty, emphasizing the importance of a quality moisture barrier.
NREL scientists have developed a unique method to increase the desirable properties of the moisture barrier, such that it has increased longevity and integrity, even in harsh conditions. The various layers of moisture barrier are resistant to delamination or separation both initially and after exposure to moisture and elevated temperature over a period of time. The properties of moisture barriers are measured as a water vapor transmittance rate (WVTR) as a function of time (days). Depending on the type of polymer and temperatures, the WVTR rates were between .004 and .530 (g/m2/day) at 100% relative humidity.Description
NREL scientists have patented a novel method and device for creating an effective moisture barrier for numerous purposes, including PV modules. The polymer layer may be fabricated from any suitable polymer including popular fluoropolymers such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or ethylene-tetrafluoroethylene (ETFE). The interfacial layer went through various test formed by atomic layer deposition (ALD). The embodiments featuring an ALD interfacial layer and deposited interfacial substance including, Al2O3, AlSiOx, TiO2, and an Al2O3/TiO2 laminate. The barrier layer associated with the interfacial layer may be deposited by plasma enhanced chemical vapor deposition (PECVD). The barrier layer may be a SiOxNy film.
The ALD acts as a protective interfacial adhesion layer for damp heat adhesion retention, and the SiOxNy layer acts as both a physical and chemical barrier to moisture transport. Barrier Improvement Factor (BIF) values for over-coated structures are as high as 260 at room temperature and almost 100 at 40°C. Device and method claims are given for this barrier test consisting of specific polymers and interfacial layers formed by ALD.Benefits
- Increase longevity and integrity of a device or product
- Better adhesion in damp heat (such as PV cell)
- PV module manufacturing
- Integrated circuit manufacturing
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Multilayer moisture barrier
A moisture barrier, device or product having a moisture barrier or a method of fabricating a moisture barrier having at least a polymer layer, and interfacial layer, and a barrier layer. The polymer layer may be fabricated from any suitable polymer including, but not limited to, fluoropolymers such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), or ethylene-tetrafluoroethylene (ETFE). The interfacial layer may be formed by atomic layer deposition (ALD). In embodiments featuring an ALD interfacial layer, the deposited interfacial substance may be, but is not limited to, Al.sub.2O.sub.3, AlSiO.sub.x, TiO.sub.2, and an Al.sub.2O.sub.3/TiO.sub.2 laminate. The barrier layer associated with the interfacial layer may be deposited by plasma enhanced chemical vapor deposition (PECVD). The barrier layer may be a SiO.sub.xN.sub.y film.
|National Renewable Energy Laboratory||04/21/2015
|Technology ID||Development Stage||Availability||Published||Last Updated|