The innovation engine for new materials

Oscar Arias


University of Chile


Chemical Engineering and Materials Engineering


Jimmy Granstrom

Faculty Sponsor(s): 

Professor Alan Heeger

Faculty Sponsor's Department: 

Materials Research Laboratory

Project Title: 

Composite Barrier Films

Project Description: 

The development of Organic Photovoltaic (OPV`s) solar cells has led to the necessity of better barrier materials in order to match flexibility requirements and minimize the permeation of oxygen and humidity present in the atmosphere. In this paper, an encapsulation architecture utilizing nitrogen gas spacers between free-standing barrier films has been characterized for its permeability, transparency and mechanical properties. Permeability was measured through a calcium optical transmission test, while transparency was characterized using an UV Vis Spectrometer, and elastic modulus at different temperatures was determined by DMA and compared to Volume Fraction theoretical model. Results show that permeability can be substantially reduced- around 3 times- by using double matrix structures with low-cost barriers. Significant gains in transparency- up to 8%- can be obtained by using antireflective films. Measurements of elastic modulus are better than expected at low temperatures, but still not good enough for OPV`s requirements. .