No abstract

Permeation barrier films are critical to a wide range of applications. In particular, for organic electronics and photovoltaics not only ultra-low permeation values are required but also optical transparency. A laminate structure thereby allows synergistic effects between different materials. Here, we report on a combination of chemical vapor deposition (CVD) and atomic layer deposition (ALD) to create in scalable fashion few-layer graphene/aluminium oxide-based nanolaminates. The resulting~10 nm contiguous, flexible graphene-based films are >90% optically transparent and show water vapor transmission rates below 7 × 10 −3 g/m 2 /day measured over areas of 5 × 5 cm 2 . We deploy these films to provide effective encapsulation for organic light-emitting diodes (OLEDs) with measured half-life times of 880 h in ambient.

Film processing procedures by means of Roll-to-Roll (R2R) for barrier coatings can often result in PV barrier films being manufactured with significant quantities of defects, which resulting in lower efficiency and a short life span. In order to improve the process yield and product efficiency it is desirable to develop an inspection system that can detect transparent barrier film defects in the production line during the film processing. Off-line detection of defect in transparent PV barrier films is difficult and time consuming. Consequently implementing an accurate in-situ defects inspection system in the production environment is even more challenging, since the requirements on positioning, fast measurement, long term stability and robustness against environmental disturbance are demanding. This paper reports on the development and deployment of two in-situ PV barrier films defect detection systems, one of them is based on wavelength scanning interferometry (WSI) and the other one is based on White Light Channeled Spectral Interferometry (WLCSI), and the integration into an R2R film processing line in the Centre for Process Innovation (CPI). The paper outlines the environmental vibration strategy for both systems and the developed auto-focussing methodology for WSI. The systems have been tested and characterised and initial results compared to laboratory-based instrumentation are presented.