Million-Fold Decrease in Polymer Moisture Permeability by a Graphene Monolayer.
Flexible, transparent, and moisture-impermeable materials are critical for packaging applications in electronic, food, and pharmaceutical industries. Here, we report that a single graphene layer embedded in a flexible polymer reduces its water vapor transmission rate (WVTR) by up to a million-fold. Large-area, transparent, graphene-embedded polymers (GEPs) with a WVTR as low as 10(-6) g m(-2) day(-1) are demonstrated. Monolayered graphene, synthesized by chemical vapor deposition, has been transferred onto the polymer substrate directly by a very simple and scalable melt casting process to fabricate the GEPs. The performances of the encapsulated organic photovoltaic (OPV) devices do not vary even after subjecting the GEPs to cyclic bending for 1000 cycles. Accelerated aging studies of working OPV devices encapsulated in the GEPs show a 50% lifetime of equivalent to 1 000 000 min, which satisfies the requirements of organic electronics.
Centre for Nanoscience and Engineering, ‡Department of Chemical Engineering, and §Department of Materials Engineering, Indian Institute of Science , Bangalore 560012, India.
Sindhu
S
Seethamraju
Centre for Nanoscience and Engineering, ‡Department of Chemical Engineering, and §Department of Materials Engineering, Indian Institute of Science , Bangalore 560012, India.
Shishir
S
Kumar
Centre for Nanoscience and Engineering, ‡Department of Chemical Engineering, and §Department of Materials Engineering, Indian Institute of Science , Bangalore 560012, India.
Krishna Bharadwaj
KB
B
Centre for Nanoscience and Engineering, ‡Department of Chemical Engineering, and §Department of Materials Engineering, Indian Institute of Science , Bangalore 560012, India.
Giridhar
G
Madras
Centre for Nanoscience and Engineering, ‡Department of Chemical Engineering, and §Department of Materials Engineering, Indian Institute of Science , Bangalore 560012, India.
Srinivasan
S
Raghavan
Centre for Nanoscience and Engineering, ‡Department of Chemical Engineering, and §Department of Materials Engineering, Indian Institute of Science , Bangalore 560012, India.
Praveen Chandrashekarapura
PC
Ramamurthy
DFT simulations; cavity ring down spectroscopy; graphene; moisture barrier; organic device encapsulation; polymer; water vapor transmission rate