Enhanced water vapor blocking in transparent hybrid polymer-nanocrystal films

Highly transparent and effective encapsulating materials have become increasingly important for photovoltaic (PV) modules to prevent water vapor molecules from permeating PV cells. The composite consists of block copolymer (PS-b-P2VP), comprised of hydrophobic and hydrophilic parts, and hygroscopic nanocrystals (Magnesium Oxide, MgO) incorporated to enhance water vapor blocking by both presenting obstacles for mass transport and also scavenging water molecules. The water vapor transmission rate (WVTR) values were reduced ∼3000 times, compared to homopolymer (PS), for both polymer and composite samples. Achieving both high transparency and low WVTR, it is expected that the composite materials can function as an excellent water vapor blocking layer for PV modules. (Figure Presented).