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.

Electrically Insulating Plasma Polymer/ZnO Composite Films

“…These results provide a potential pathway to adjust the bulk and surface properties of other plasma polymers that have previously been shown to display antibacterial activity [38,39,40,41] or attractive optoelectronic properties [42,43,44,45]. For example, plasma polymerized γ-terpinene thin films have shown sufficient optical transparency and photostability to be used for the encapsulation of PCPDTBT: PC 70 BM solar cells to prevent loss of efficiency [46,47], whereas polymers derived from terpinen-4-ol and linalool have been proposed as insulating interlayers in flexible electronic devices [48,49]. It can also potentially provide the means for in situ functionalization of vertically aligned graphene networks that have been fabricated from essential oils using the same plasma set-up [50,51] to improve their properties for such applications as sensing and energy storage.…”

A Review on Encapsulation Technology from Organic Light Emitting Diodes to Organic and Perovskite Solar Cells

“…Reproduced with permission. [ 179 ] Copyright 2017, Springer Nature. d) SEM cross section of Al 2 O 3 encapsulated device and device schematic of solar cells with Al 2 O 3 encapsulation.…”

“…The encapsulated solar cells maintained 61.5% of the initial efficiency after 1920 h in the ambient environment (Table 2). [ 179 ] Several inorganic films (such as silicon‐based film and TiO 2 /Al 2 O 3 oxide films) and polymer organic films have been successfully utilized as encapsulation materials for OPVs devices based on the previous results. Even though these films are still permeable to water molecules and oxygen due to the pinhole defects or the pores in the surface, these films, as encapsulation layers, have stabilized the devices’ performance to a large extent.…”

Plant Secondary Metabolite-Derived Polymers: A Potential Approach to Develop Antimicrobial Films

“…The uniformity indicates that polymerization reactions occurred on the surface of the substrate in preference to the gas phase. Moreover, ultra-smooth surfaces (with an average roughness of less than 1 nm) were attained for plasma polymerization of various PSMs, which is a particularly significant factor that may influence the initial microbial adhesion [ 164 , 165 ]. It is worth to mention that the properties of the surface of plasma polymerized films make them highly susceptible to growth conditions, especially the input power, where more energetic ions can cause more surface bombardment and etching.…”