title: Photostability of plasma polymerized γ-terpinene thin films for encapsulation of OPV.
abstract: Optically transparent, smooth, defect-free, chemically inert and with good adhesion to a variety of substrates, plasma polymers from plant-derived secondary metabolites have been identified as promising encapsulating materials for organic electronics and photovoltaics. Here, we demonstrate that an encapsulating layer of plasma polymerized γ-terpinene reduces degradation-related loss in conversion efficiency in PCPDTBT:PC70BM solar cells under ambient operating conditions. The stability of γ-terpinene films was then investigated under extreme UV irradiation conditions as a function of deposition power. When exposed to ambient air, prolonged exposure to UV-A and UV-B light led to notable ageing of the polymer. Photooxidation was identified as the main mechanism of degradation, confirmed by significantly slower ageing when oxygen was restricted through the use of a quartz cover. Under unnatural high-energy UV-C irradiation, significant photochemical degradation and oxidation occurred even in an oxygen-poor environment.
authors.affiliation: School of Chemistry, Physics, and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD 4000, Australia.|Electronic Materials Research Lab, College of Science and Engineering, James Cook University, Townsville 4811, Australia.
authors.forename: Kateryna
authors.initials: K
authors.lastname: Bazaka
authors.affiliation: Electronic Materials Research Lab, College of Science and Engineering, James Cook University, Townsville 4811, Australia.
authors.forename: Jakaria
authors.initials: J
authors.lastname: Ahmad
authors.affiliation: Applied and Green Photochemistry Group, College of Science and Engineering, James Cook University, Townsville 4811, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Oelgemöller
authors.affiliation: School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, 2052 Sydney, Australia.
authors.forename: Ashraf
authors.initials: A
authors.lastname: Uddin
authors.affiliation: Electronic Materials Research Lab, College of Science and Engineering, James Cook University, Townsville 4811, Australia.
authors.forename: Mohan V
authors.initials: MV
authors.lastname: Jacob